posterabstracts / poster abstracts

Sediment 2007

Posterabstracts

Geo.Alp, Vol. 4, 2007 39

SSeeddiimmeenntt 22000077

TTHHEE LLAATTEE TTRRIIAASSSSIICC HHAAUUPPTTDDOOLLOOMMIITTEE SSEECCTTIIOONN WWIIEESSTTAALLSSTTAAUUSSEEEE NNEEAARRHHAALLLLEEIINN ((NNOORRTTHHEERRNN CCAALLCCAARREEOOUUSS AALLPPSS,, AAUUSSTTRRIIAA)):: BBIIOOMMAARRKKEERR EEVVIIDDEENNCCEE FFOORR TTHHEE FFOORRMMAATTIIOONN

OOFF OORRGGAANNIICC--RRIICCHH SSUUCCCCEESSSSIIOONNSS IINN SSMMAALLLL SSCCAALLEE BBAASSIINNSS WWIITTHHIINN CCAARRBBOONNAATTEE PPLLAATTFFOORRMMSS

A. Bechtel1,2, H.-J. Gawlick1, R. Gratzer1, M. Tomaselli1, and W. Püttmann3

1 Department Angewandte Geowissenschaften und Geophysik, Montanuniversität Leoben, Peter-Tunner-Str. 5, A-8700 Leoben,Austria

2 Institute of Mineralogy and Petrology, University of Bonn, Poppelsdorfer Schloss, D-53115 Bonn, Germany3 Institute of Atmospheric and Environmental Sciences, Department of Environmental Chemistry, J. W. Goethe-Universität,

Georg-Voigt-Str. 14, D-60054 Frankfurt a.M., Germany

The origin of organic-bearing reducing sedimentswithin the Late Triassic Hauptdolomite/Dachstein carbon-ate platform of the Northern Calcareous Alps, a subject ofsome debate, is clarified by microfacies biomarker analy-ses that enable the characterization of the depositionalenvironment of the Norian dolomicrites (Hauptdolomite)of the Wiestalstausee section (Lower Tirolic nappe,Salzburg Calcareous Alps). By examining the section usingthe oxygen-restricted biofacies (ORB) classification, wefind ORB 1-4 mostly in the dark grey organic- rich sedi-ments and ORB 6, or normal oxygen conditions for thelight grey dolomites. Anaerobic biofacies, characterizedby the total absence of benthic organisms and a fissilesediment fabric, predominate for most of the dark greyand micritic parts of the section. The laminated dolomi-crites show ORB 3 and ORB 4, containing very few benthicspecies, which are abundant on some bedding planes inORB 4. Here, the sediment fabric is planar laminated, butlimited bioturbation may occur. This sediment type corre-sponds to the poikiloaerobic and episodically dysaerobicfacies.

The n-alkane distribution patterns and relative intensi-ties of steranes are typical for organic matter of predomi-nantly algal and/or microbial origin with minor contribu-tions from land plants. Phytoplankton (including dinofla-gellates) and photosynthetic bacteria are considered asthe major primary producers of the biomass accumulatedwithin the immature, carbonate-rich rocks. High contentsof hopanoid biomarkers and constituents related to thearborane/fernane skeleton are considered to be of bacter-ial origin and indicate enhanced microbial activity in thesedimentary environment. However, a terrestrial origin(from land plants) of the arborane/fernane-derivativescannot be excluded. The occurrence of aryl isoprenoids,probably derived from carotenoids of the photosynthetic

green sulfur bacteria (Chlorobiaceae), indicates the estab-lishment of euxinic conditions in the bottom water.

Comparable diagenetic degradation mechanisms ledto the formation of hopanes and hop-17(21)-enes.Methylated chromans occur in low abundance, and thepredominant occurrence of trimethylated C29 chroman(tri-MTTC) over dimethylated C28 chroman (di-MTTC) indi-cates enhanced salinity in the upper part of the water col-umn. Diagenetic conversion of organic matter underanoxic conditions in a high-sulfur environment due tosalinity stratification are further indicated by low Pr/Phvalues and high contents of the C35 benzohopane com-pared to the C32 to C34 homologues. The relative propor-tions of S/R isomers of the !!! C29 steranes and the!" C31 hopanes are consistent with an organic mattermaturity equivalent to vitrinite reflectance values of~0.5% Rr. This maturity assessment is further confirmedby the predominance of monoaromatic over triaromaticsteroids.

In the present study, the interaction of salinity varia-tions, water column stratification, and the establishmentof anoxic conditions within a restricted carbonate plat-form is highlighted using molecular indicators. For thefirst time, sedimentological and geochemical featuresprovide evidence for the establishment of small-scaleanoxic basins through erosion by currents or from theremnants of channels, which were possibly isolated peri-odically by small scale sea level changes. Changes in car-bonate production also may play a role. Beside tectonical-ly induced formation of anoxic basins in the Late Triassiccarbonate platform (e.g., Seefeld basins), this mechanismmay contribute to the enhancement of the hydrocarbonpotential of the Hauptdolomite/Dachstein carbonateplatform of the in the whole western Tethyan realm.

Geo.Alp, Vol. 4, 200740


TTHHEE SSEEDDIIMMEENNTTOOLLOOGGIICCAALL,, PPAALLEEOONNTTOOLLOOGGIICCAALL AANNDD GGEEOOCCHHEEMMIICCAALL IIMMPPLLIICCAATTIIOONNSS OOFF TTHHEE BBAASSAALLCCHHOOTTEE!! EEVVEENNTT ((MMIIDDDDLLEE DDEEVVOONNIIAANN,, EEIIFFEELLIIAANN)) IINN PPRRAAGGUUEE BBAASSIINN ((CCZZEECCHH RREEPPUUBBLLIICC))

Stanislava Berkyová and Ji"í Fr!da

Stanislava Berkyová, Charles University, Faculty of Science, Department of Geology and Paleontology; [email protected] 6, 128 43 Prague and Czech Geological Survey, Geologicka 6, 150 00 Prague, Czech Republic;Ji"í Fr!da, Czech Geological Survey, Geologicka 6, 150 00 Prague, Czech Republic; [email protected]

The Basal Chote# event, first named by House (1985)and typified by sequences in Bohemia (Chlupá# and Kukal,1986) has been documented in Central and Southern Eu-rope (e.g. Chlupá# et al. 2000), North Africa (e.g. Beckerand House 1994), Southern America (Troth 2005), NorthAmerica (Ver Straeten 2005), Siberian platform (Yolkin etal. 2005) and therefore it is regarded as an importantglobal geo-event. In its type area (Prague Basin) the afore-mentioned event falls at the boundary between the T"e-botov Limestone (Emsian/Eifelian) and the Chote# Lime-stone (Eifelian) and their equivalents, close above theLower-Middle Devonian boundary. It is correlated withthe base of the Pinacites jugleri and Polygnathus costatuscostatus biozons. The TT""eebboottoovv LLiimmeessttoonnee is mostly a bio-clastic wackestone-packstone with a relatively high bio-genic content and intense bioturbation. The presence ofmicritic matrix, benthic fauna typical for muddy bottomenvironments and absence of sedimentological featuresindicating current activity suggest a calm, low-energy,relatively deep sedimentary environment rich in free oxy-gen (inferred from intense bioturbation and diverse ben-thic assemblages). The sedimentary environment is inter-preted here as proximal offshore, bellow storm wave base.The CChhoottee## LLiimmeessttoonnee, on the other hand, reflects in itsdevelopment and fossil content perturbation and nonsteady state conditions. The above mentioned limestone isrepresented by the alternation of well-sorted peloidalpackstone/grainstone and dark limemudstone/wacke-stone and are regarded here as a representatives of tem-pestites, reflecting in its development eustatic oscillationsin sea level.

AAcckknnoowwlleeddggeemmeennttss

The research is supported by the grant of Grant Agencyof the Academy of Science of the Czech Republic

(KJB307020602). It represents our contribution to theIGCP 499.

Becker, R.T. & House, M. R. (1994): International Devoniangoniatite zonation, Emsian to Frasnian, with newrecords from Morocco. – Cour. Forsch. Inst. Senckenb.,169: 79–135.

Chlupá#, I. & Kukal Z. (1986): Reflection of possible globalDevonian events in the barrandian area, C.S.S.R. – In:Lecture Note in Earth Sciences, Global Bio-events, ed.O. Walliser, 169–179, Springer-Verlag, Berlin.

Chlupá#, I., Feist, R. & Morzadec, P. (2000): Trilobites andstandard Devonian stages. – In: Bultynck, P. (Ed.), Sub-commision on Devonian Stratigraphy: Fossils GroupsImportant for Boundary Definition. – Cour. Forsch. Inst.Senckenb., 220: 87–98.

House, M. R. (1985): Correlation of mid-Palaeozoicammo noid evolutionary events with global sedimen-tary perturbations. – Nature, 313:17–22.

Troth, I. (2005): When did the Malvinokaffric real break-down? – In E. A. Yolkin (ed.): Contributions to the IGCP499 Project (Devonian Terrestrial and Marine environ-ments: From Contient to Shelf. Novosibirsk, PublishingHouse of SB RAS, 2005.

Ver Straten C. A. (2005): The Late Pragian, Emsian, AndEifelian in the Appalachian Basin, Eastern U.S.A. – In E.A. Yolkin (ed.): Contributions to the IGCP 499 Project(Devonian Terrestrial and Marine environments: FromContient to Shelf. Novosibirsk, Publishing House of SBRAS, 2005.

Yolkin E.A., Izokh N.G., Obut O.T. & Kipriyanova, T.P. (2005):Field Excursion Guidebook to the IGCP 499 Project (De-vonian Terrestrial and Marine environments: FromContient to Shelf). – Novosibirsk, Publishing House ofSB RAS, 2005.

Geo.Alp, Vol. 4, 2007 41


PPAALLEEOOMMEETTEEOORROOLLOOGGYY OOFF DDUUSSTT EEVVEENNTTSS

Stephan Dietrich1, Klemens Seelos1, and Frank Sirocko1

1 Johannes Gutenberg-Universität Mainz, Institut für Geowissenschaften; [email protected]

16 long sediment cores from Eifel dry maar lakes havebeen drilled between 1999 and 2005 by the ELSA project(Eifel Laminated Sediment Archive) and document the last0 - 140 ka. In this project we will evaluate in detail distinctdust layers, which can be correlated between the cores.

Dust phases (dry and cool winds > 5m/s) over the conti-nent have been related to the cold events in the Greenlandice and North Atlantic sea surface temperature patterns(Seelos & Sirocko, 2006). A continuous dust stack (0-140 ka)for Central Europe is presented by Seelos & Sirocko (2007).

Grain size analysis of individual dust layers is done bythe automated method of ultra high-resolution grain sizemeasurements from thin sections, which was developedby Seelos & Sirocko (2005). The grain size composition ofindividual dust layers between MIS 5e and MIS 1 will bedetected in all available cores and will be evaluated for 20statistical grain size parameters. Gradients in layer thick-ness, mineralogy, geochemistry (measured by an EAGLE IIµXRF) and the grain size composition is used to quantifythe principle paleowind direction via the fingerprints ofthe sediment sources, which is a first indication about themeteorology that lead to the dust transport.

The further objectives of the project are the compari-son of observed wind directions with existing model datafor atmospheric circulation during MIS 5 to MIS 1. Thecomparison of the regional dust storms in the Eifel withthe large scale patterns of dust transport in the northern

hemisphere, as documented in the North GRIP dust parti-cle record (Ruth et al. 2003), should indicate if dust stormsin the Eifel are associated with large hemispheric weatherextremes (high pressure cells over eastern Europe andSiberia or storms in the west wind drift) and thus with ahemisphere wide forcing process or only local/regionalweather anomalies in the Eifel.

Seelos, K. & Sirocko, F. (2007): The development of a con-tinuous dust / loess stack (0-140 ka) for Central Europeby using the particle analysis and detection system RA-DIUS on ELSA sediment cores (Eifel, Germany). – Geo-physical Research Abstracts, Vol. 9, 02804.

Seelos, K. & Sirocko, F. (2006): Abrupt cooling events atthe very end of the last interglacial. – In: Sirocko, F.,Claussen M., Sanchez Goni, M.F. & Litt, T. (Eds); ’The Cli-mate of Past Interglacials’. Elsevier, Amsterdam.

Seelos, K & Sirocko, F (2005): RADIUS - Rapid ParticleAnalysis of digital images by ultra-high-resolutionscanning of thin sections. – Sedimentology, 52,669–681.

Ruth, U., Wagenbach, D., Steffensen, J. P., Bigler & M.(2003): Continuous record of microparticle concentra-tion and size distribution in the central GreenlandNGRIP ice core during the last glacial period. – Journalof Geophysical Research, 108 (D3), 4098.

Geo.Alp, Vol. 4, 200742


SSEEDDIIMMEENNTTOOLLOOGGIICCAALL,, GGEEOOCCHHEEMMIICCAALL AANNDD MMIICCRROOPPAALLEEOONNTTOOLLOOGGIICCAALLIINNVVEESSTTIIGGAATTIIOONNSS OOFF LLAAKKEE SSEEDDIIMMEENNTTSS TTOO RREECCOONNSSTTRRUUCCTT LLAATTEE GGLLAACCIIAALL//HHOOLLOOCCEENNEE LLAANNDDSSCCAAPPEE

EEVVOOLLUUTTIIOONN AATT LLAAGGOO BBUUDDII ((CCHHIILLEE))

Stefan Doberschütz, Dirk Nowacki, Gerhard Daut, Brunhilde Dressler,Steffi Faber, Peter Frenzel, Theresia Klötzing, Roland Mäusbacher, Mario Pino, and Johannes Wallner

Department of Geography, University of Jena, Löbdergraben 32, D-07737 JenaCorresponding address: S. Doberschütz; [email protected], Fax: +49 (0) 3641 948812, Phone: +49 (0) 3641 6986850

The coastal lagoon Lago Budi, located in southern Chile(38.9° S) can be characterized through elevated ranges ofsalinity (7– ~20 ppm), which arise from a spatial connec-tion to the Pacific Ocean. Due to its location, Lago Budiserves as a sediment trap, indicating Holocene landscapeevolution.

During a field campaign (German Research FoundingProject “Late Glacial/Holocene Landscape Evolution atLago Budi, Chile (38.9° S) - Paleoseismic Investigations onLake Sediments”) several piston cores were taken to obtaindetailed information on intra-lagoon sedimentationprocesses. Furthermore, the compilation and dating oftsunamigenic sediments should allow a deeper under-standing of seismic events and associated tsunami waveson a temporal and regional scale. The influence of suchsingular events on lake chemistry and the correspondingmicrofauna also has to be taken into account.

Thus, the aim of the current study was to develop amulti-proxy approch providing the possibility to recon-struct Late Glacial / Holocene landscape evolution with si-multaneous consideration of ecosystem modificationsmainly caused by the input of allochtonous tsunamigenicsediments.

Based on the analysis of one piston core with a totallength of 6 meters a wide range of sedimentological, geo-

chemical and microfaunistical methods was carried out inreconstructing marine, brackish and freshwater condi-tions, reflecting a weakening respectivly strengthening ofthe marine impact. To distinguish event-associated dis-turbances and long-term modifications of the ecosystemgrain-size analysis were performed by using laser diffrac-tion technology. In combination with measurements ofthe magnetic susceptibility several sandy layers could bedetected, indicating the existence of tsunamigenic de-posits within the lake. In addition, X-ray diffractometrymeasurements enabled us to determine the origin andstructural composition of these layers.

The results of geochemical analysis primarily based onatomic absorption spectrometry and CNS were used todeviate a chronological sequence of different types of pa-leoenvironments in terms of salinity and nutrient content.Furthermore Corg/N-ratios were calculated to identify theinfluence of terrigenous input.

One of the main focuses of our study was the use of mi-cropaleontological indicators. By applying a paleoecolog-ical approach, several taxa of foraminifera, ostracods andmolluscs representing brackish respectivly marine envi-ronments were identified and analysed quantitatively toreconstruct past habitat characteristics.

Geo.Alp, Vol. 4, 2007 43


CCOOMMPPOOSSIITTIIOONN AANNDD OORRIIGGIINN OOFF SSAANNDDSSTTOONNEESS AANNDD TTUUFFFFAACCEEOOUUSS SSAANNDDSSTTOONNEESSOOFF TTHHEE BBEEAACCOONN SSUUPPEERRGGRROOUUPP IINN NNOORRTTHHEERRNN VVIICCTTOORRIIAA LLAANNDD,, AANNTTAARRCCTTIICCAA

Martin Elsner1, Robert Schöner1, Lothar Viereck-Götte.1,Michael Abratis1, Benjamin Bomfleur2, Jörg Schneider3, and Reinhard Gaupp1

1 Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena2 Geologisch-Paläontologisches Institut, Forschungsstelle für Paläobotanik, Westfälische Wilhelms-Universität Münster3 Institut für Geologie, Bereich Paläontologie, TU Bergakademie Freiberg

An up to 300 m thick succession of clastic and volcani-clastic sediments of the Beacon Supergroup overlying apre-Devonian crystalline basement crops out in northernVictoria Land below the mafic plateau-lavas of the mid-Jurassic Ferrar Large Igneous Province. These Triassic toEarly Jurassic sediments document the period directlypreceding the Ferrar Magmatism that was associated withthe initial break-up of Gondwana. So far neither prove-nance of the sediments nor the basin evolution have beeninvestigated in detail.

The sediments of fluvial and minor lacustrine origin aredivided into the lower Section Peak Formation (SPF) of ap-proximately 200-250 m thickness, which is dominated byquartzose sandstones, and the upper, informally namedShafer Peak Formation (SHF), consisting almost exclusive-ly of reworked rhyolitic fall-out ashes. A Late Triassic toEarly Jurassic biostratigraphic age can be deduced fromDicroidium-floras in the SPF and floras dominated by cy-cadophytes and dipterid ferns (lacking Dicroidium) in theSHF. The sedimentary succession is intruded by syn- topostsedimentary mafic sills. Associated with the synsedi-mentary magmatism are local mafic tuff deposits formedby phreato-magmatic eruptions, the so called ExposureHill Type Events. The crystalline basement in this area isformed by the early Palaeozoic Ross Orogen, which con-sists mainly of amphibolite to granulite facies metasedi-mentary rocks (Rennick and Priestley Shists, WilsonGneiss) and the granodioritic Granite Harbour Intrusives.

The sandstones of the SPF are predominantly sub-litharenites and lithic subarkoses. Sorting and roundnessof the grains are generally moderate to poor. Apart fromthe dominant quartz grains they consist mainly of alkalifeldspars, plagioclase, metamorphic lithoclasts and vol-canic rock fragments of variable chemistry. The most fre-quent heavy mineral is garnet, only subordinately occurtourmaline, zircon, green hornblende and epidote.

The textural and compositional immaturity of thesandstones indicates a relatively proximal source area. Thesandstone compositions plot in the QmFL-provenance dia-gram in the recycled orogen field, which seems to suggest

the underlying Ordovician Ross orogen as source of thesediments. The frequent occurrence of volcanic detritus ofvarying chemical composition has been interpreted inprevious models as indication of an active volcanic arc atthe Panthalassan (Proto-Pacific) margin. Another, closersource could be the remnant magmatic arc of the Rossorogen. However, mineral chemistry of garnets from theSPF show obvious differences to published garnet analy-ses of local basement rocks, so that an additional sourcearea is necessary, possibly the East Antarctic Craton. Mi-croprobe data of feldspar show that Ferrar volcanism wasnot coeval to deposition of sandstones during the SPF assupposed by previous authors.

Still within the upper parts of the SPF greenish-grey tobeige tuffaceous sand- to siltstones are intercalated form-ing a transition to the overlying, 40-50 m thick SHF. Evi-dence of fluvial reworking is frequent, whereas true air-fall-deposits have not been identified in the SHF so far. Thetuffaceous material is very well sorted with fine sand tocoarse silt size consisting predominantly of rhyolitic shards,angular quartz, alkali feldspar, and plagioclase. The shardsrarely exhibit bubble wall or bubble junction shape, but arein most cases fragmented due to fluvial reworking. Addi-tionally they are secondarily altered to zeolites (clinoptilo-lite/heulandite) and sometimes to smectites. While most ofthe analysed samples show varying cathodoluminescencecolours for each mineral species, so far one horizon hasbeen found with mineral fragments nearly exclusively ofplagioclase (An30) and magmatic quartz. This is interpretedas juvenile material, thus allowing determination of origi-nal magma and phenocryst chemistry.

The SHF can be interpreted as a lithological equivalentof the upper part of the Hanson Formation in the CentralTransantarctic Mountains, more than 1000 km away. Theoccurrence of rhyolitic tuffs over such a range along theTransantarctic Mountains requires a distal, ultra-plinianvolcanism of yet unknown source. However, a volcanicprovince of this age and chemistry can be found in theMount Poster Formation (Ellsworth Volcanic Group) onthe Antarctic Peninsula.

Geo.Alp, Vol. 4, 200744


PPRREELLIIMMIINNAARRYY NNOOTTEE OONN TTHHEE HHEELLVVEETTIICC UUNNIITTSS AATT GGEEOOTTOOPPEE LLAANNGGEERR KKÖÖCCHHEELLDDIISSTTRRIICCTT GGAARRMMIISSCCHH--PPAARRTTEENNKKIIRRCCHHEENN,, SSOOUUTTHHEERRNN BBAAVVAARRIIAA,, GGEERRMMAANNYY)) AANNDD TTHHEE FFIIRRSSTT

DDIISSCCOOVVEERRYY OOFF FFOOSSSSIILL RREESSIINN IINN TTHHEE FFRREESSCCHHEENN BBEEDDSS ((LLAATTEE AAPPTTIIAANN––AALLBBIIAANN))

Hubert Engelbrecht1, Karl B. Föllmi2, Ursula Baumer3, and Johann Koller3

1 Hess-Straße 96, D-80797 Munich, Germany; [email protected] Université de Neuchâtel, Faculté des Sciences, Institut de géologie, Emile Argand 11, Case postale 158, CH-2009, Neuchâtel

(Switzerland); [email protected] Doerner Institut, Barerstraße 29, D-80797 Munich, Germany; [email protected]

IInnttrroodduuccttiioonn:: The Helvetic Units present at Langer Köchelare part of the external zone of the Northern Alpine fold andthrust belt (Schmid et al. 2004: Eclogae geol. Helv., 97,93–117, Basel) in Southern Bavaria. According to Roeder &Bachmann (Mém. Mus. natn. Hist. nat., 170, 263-284, Paris,1996), these Helvetic Units form narrow slivers, consisting ofsteep-flanked, tight and faulted antiformal stacks of thrust-ed sheets between the detached folded Molasse Units (foot-wall) to the North and Flysch Units (hanging wall) to theSouth.

In 1998, for the first time, a cm-sized pebble of fossil resinwas found in glauconitic quartzsandstone, exploited at thequarry Hartsteinwerk Werdenfels, which was active from1927–1999 at the southern flank of the hump LangerKöchel.

SSttrraattiiggrraapphhyy:: It starts at the base with monotonous, darkgrey and black colored, slightly bituminous, thinly beddedand laminated marlstones attributed to the Drusberg For-mation. The presence of Conorotalites sp.- probably Cono -rotalites bartensteini intercedens - indicates an early lateBarremian age. The stratigraphic passage to lithologies com-parable to the Grünten Member - basal part of the Garschel-la Formation (Linder et al. 2006: Eclogae Geol. Helv., 99/3:327–341) – is set, where the first intercalation of dark greycolored, dm-thick, marly limestone layers occurs. The sequence is made up of dark grey, laminated marlstone bedsup to 1,3 m thick, alternating with grey to dark grey colored,often nodular and in places burrowed, marly limestone stra-ta (max. thickness 70 cm). A late early Aptian age of this unitis supposed. The thickness of this sequence diminishes fromca. 90 m at the western part of Langer Köchel to only a fewmeters at the eastern side. The stratigraphic contact at theupper boundary of this member signalizes an important andsharp erosional unconformity. The lithologies above - com-parable to the Freschen Beds – are made up of medium tocoarse grained, dark olive, grey to dark grey colored, mediumto very thick bedded, moderately sorted, calcareous andglauconitic quartzsandstone layers (maximum thickness3,6 m), which are rarely separated by dark grey marlstonelayers up to 27 cm thick. The strata, often laminated on mm-and cm-scale, are confined by plane or hummocky super-and subfaces. Close to the base of the upper quarter of this

unit, an incompletely graded, 49 cm thick quartzsandstonelayer was observed. Above, dm- to m-thick horizons – later-ally persistent on 10 m-scale – with significant features ofredeposition (cm- to dm-scaled, rounded intraclasts in in-tensely convoluted quartzarenaceous matrix) are present.The macrofossil content of this unit consists of Birostrinaconcentrica and ammonites, which are still under examina-tion. Ichnolites (Palaeophycus, Thalassinoides) are common.

The microfauna from the basal layer of the unit yieldedLenticulina sp., Novalesia sp., Marsonella sp. and Gaudryinasp. According to correlatives present in the distal Helveticrealm, the age of the Freschen Beds is probably late Aptian toAlbian; its thickness is ca. 140 m. It is supposed that itslithologies represent redeposited matter from the Brisi-,Gamser- and Rankweiler depositional areas on the adjacentplatform and slope. The passage to the Seewen Formation(Cenomanian - Santonian) is marked by an erosional uncon-formity. It starts with amalgamated redeposits < 1m (GötzisBeds), which are overlain by pelagites consisting of greylimestone layers, followed by an alternance of brick red andbeige colored, marly limestones.

FFoossssiill rreessiinn aanndd ppaalleeooeennvviirroonnmmeenntt:: Gas chromatographicand mass-spectroscopic analysis of the fossil resin revealedthe total defunctionalization and dealkylation of its con-stituents. Only traces of a few biomarkers have survived – forinstance agathalene –, which indicates its botanic originfrom agathic acid: The conifer species Agathis dammara andA. australis containing this resin at present only occur in themontane subtropical-tropical forests. It is therefore sup-posed that the paleogeographic provenance of the Werden-fels fossil resin has been a distant mainland positioned fur-ther to the east or southeast at low latitude, from where itwas transported – attached to driftwood – by surface cur-rents across the late Aptian - Albian Tethys to the HelveticRealm. It is pointed out that transport and deposition of thisfossil resin pebble is linked up with the Cretaceous paleoen-vironmental development: The Aptian climate change,which proliferated continental fluvial runoff and the flux ofterrigenous matter into westbound longshore currents con-touring the Southern European continental margin (Puceatet al. 2005: Earth and Planetary Science Letters, 171/1,149–156), enhanced the likelihood of dropstone deposition.

Geo.Alp, Vol. 4, 2007 45


TTHHEE LLOOWWEERR MMIIOOCCEENNEE PPFFÄÄNNDDEERR--DDEELLTTAA OONN TTHHEE SSOOUUTTHHEERRNN CCOOAASSTT OOFF TTHHEE MMOOLLAASSSSEE BBAASSIINN

Dorothea Frieling and Bettina Reichenbacher

Department of Earth and Environmental Sciences, Section Palaeontology, Ludwig-Maximilians University of Munich,Richard-Wagner-Str. 10, D-80333 München

The NNE-SSW-oriented Pfänder ridge east of LakeConstance (south-western Germany) marks the forelanddip panel defining the southern margin of the autochtho-nous Molasse in this area and is composed of a successionof clastic sediments of the Lower Freshwater Molasse, theUpper Marine Molasse and the Upper Freshwater Molasse.This sequence was controlled by the activity of an alluvialfan, the Pfänder Fan, which was situated between theHörnli Fan to the west at the mouth of the Paleo-Rhineand the Hochgrat Fan to the east at the mouth of thePaleo-Iller. It did not nearly obtain the dimension of thesevery large fans, but it is detectable as an independent fansince the Lower Miocene [5]. In Lower Miocene times,when the marine Eggenburgian transgression invaded thisarea, a deltaic complex began to prograde in front of thefan at the coast of the Molasse Sea. Deposits of this deltaiccomplex within the Upper Marine Molasse are well ex-posed in deep gorges at the southern and south-easternslope of the Pfänder ridge between Bregenz (Vorarlberg)and Siebers near Weiler (Allgäu/Germany).

The sharp and erosive base of the Upper Marine Mo-lasse is marked by fluvial conglomerates, which arechannel sediments of a proximal facies of a progradingalluvial fan, representing the basal low stand tract of theUpper Marine Molasse. It is overlain by a 50 to 110 mthick monotonous shoreface-succession of glauconiticsandstones on a transgressive surface, representing atransgressive systems tract. This facies type is detectablein all of the studied sections as well as the sections in thevicinity [4]. Above this part of the sequence the increas-ing activity of the prograding delta complex is de-tectable by deposits reflecting a higher energetic systemwith much coarse-grained sediments deposited withinchannels fed by a fluvial system. This part of the se-quence is clearly influenced by tidal activities proven bymegaripples and heterolithic facies types. In contrast tothe basal third these parts of the sections, which weregenerated since the delta has been active, are not paral-lelizable even in closely neighboured sections. This factwas interpreted as the internal structure of the delta di-

vided into different lobes and bays between [4]. Thedeltaic complex is interpreted as a high stand systemstract which is subdivided into several subordinated smallcycles. In the talus centre, in the area around the Wirta-tobel gorge, for example two terrestrial horizons are detectable; the second is well known because of its coalmining (vitrain) near Bregenz from 1840 until afterWorld War II [2]. These terrestrial horizons represent adelta plain environment in the centre of the distributaryfan, thinning out toward northeast. The heterogenic de-posits of the active delta complex are overlain by marlsof the transition zone or fine-sands of the lowershoreface in the north-eastern sections, respectively.This upper part of the sequence represents a new trans-gressive systems tract, may be the high stand systemstract is included, too. It shows the highest sea level of theUpper Marine Molasse Sea, the phase of the maximumtransgression [4]. The top of the whole sequence of ap-proximately 400 m thickness is cut by a sharp erosionalplane, containing in all probability the regressive sys-tems tract. It is overlain by thick coarse-grained con-glomerates of the Upper Freshwater Molasse.

Because of the local character of a fan, controlled bytectonics, climate, compaction and subsidence, the de-scribed sequence-stratigraphic interpretation of thePfänder succession is not clearly parallelizable with thegeneral cyclic structure of the Upper Marine Molasseknown from the Swiss [1] and German [3, 6] foreland Mo-lasse.

[1] Büchi, U.P. (1955), Eclog. geol. Helv. 48.[2] 257-321; [2] Gümbel, W.v. (1896), Oesterr. Zeitschr.

f. Berg- und Hüttenwesen 44: 115–121.[3] Lemcke, K., Engelhardt, W.v. & Füchtbauer, H. (1953),

Beih. Geol. Jb, 11: 1–182.[4] Schaad, W., Keller, B. & Matter, A. (1992), Eclog.

geol. Helv. 85/1: 145–168.[5] Schiemenz, S. (1960), Beih. Geol. Jb. 38: 1–119.[6] Wenger, W.F. (1987), Zitteliana, 16: 173–340.

Geo.Alp, Vol. 4, 200746


AAPPPPLLIICCAATTIIOONN OOFF GGRROOUUNNDD--PPEENNEETTRRAATTIINNGG RRAADDAARR IINN TTHHEE DDEEAATTHH VVAALLLLEEYY FFIIEELLDD SSIITTEE::IINNFFLLUUEENNCCEE OOFF FFEERRRROOMMAAGGNNEETTIICC MMIINNEERRAALLSS OONN TTHHEE

PPRROOPPAAGGAATTIIOONN OOFF EELLEECCTTRROOMMAAGGNNEETTIICC WWAAVVEESS SSEENNDD OOUUTT BBYY GGPPRR

Nadja Fritschka1, Jörg Lang1, Matthias Greb2, Uli Bieg2, Jens Hornung2, Anke Friedrich3, and Matthias Hinderer2

1 Institute for Geology and Palaeontology, Leibniz University of Hannover, Callinstr. 30,30167 Hannover, Germany

2 Institute for Applied Geosciences, Technical University of Darmstadt University, Schnittspahnstr. 9,64287 Darmstadt, Germany

3 Department für Geo- und Umweltwissenschaften, Ludwigs-Maximilians Universität München, Luisenstr. 37,80333 München, Germany; [email protected]

Originally the study wanted to test the utility ofground-penetrating radar (GPR) in three dimensionalimaging alluvial fans in the Death Valley. The test area waschosen due to its prominent alluvial fans flanking themountain fronts. Lack of vegetation and easy accessibilityof fan surfaces combined with coarse-grained sedimentsand deep groundwater levels seemed to fit perfect for applying the GPR on the sedimentary architecture. Ex-pecting a deep penetration depth of the electromagneticwave with an excellent signal, we measured shallow pene-tration depth with a low signal to noise ratio. Moreoverwe measured high inductivity effects on the cable linkingthe antennas and the processing unit. Aiming to under-stand the attenuation and scattering effects of the elec-tromagnetic wave we conducted a GPR “reference” surveyusing different antennas ranging from 60 to 200 MHZ Although the overall signal to noise ratio was very lowwith “multiple reflectors”, using higher frequencies thequality of the radargrams improved.

To verify the source of attenuation and scattering, sed-iment susceptibility was measured on different desertpavements, including the measurement of fines and arepresentative portion of different rock types, trying to

consider the different catchments and their underlyinglithologies. Measurements were taken on the western andeastern flank of the Death Valley. High susceptibility val-ues of around 0.1 to 43 (normally values are around 0.01)showed in a clear way that there are abundant ferro -magnetic minerals in all alluvial fan deposits.

Although it is known that the electromagnetic waveconsists of an electric- and magnetic part, oscillating per-pendicular towards each other, it is not described in litera-ture that magnetic properties of the underlying sedimentcan influence the propagation of the electromagneticwave. Due to high magnetic susceptibility values we pro-pose, that the electromagnetic wave will be reflected andscattered at the surface and gain only shallow penetrationdepth. The higher the used GPR frequency, the higher wasthe inertia of the magnetic dipoles in the grains and thusthe higher was the penetration depth.

Although the GPR was not able to image the deeper architecture of alluvial fans, it provided some insights intothe filling history of the active channels where the transi-tion from the most recent fluvial deposits and alluvial fanbedrock was mapped.

Geo.Alp, Vol. 4, 2007 47


RRAADDIIOOLLAARRIITTIICC--OOPPHHIIOOLLIITTIICC MMEELLAANNGGEE AANNAALLYYSSIISS::NNEEWW PPOOTTEENNTTIIAALL FFOORR PPAALLAAEEOOGGEEOOGGRRAAPPHHIICC RREECCOONNSSTTRRUUCCTTIIOONNSS OOFF LLOOSSTT OOCCEEAANNSS AASS

DDEEMMOONNSSTTRRAATTEEDD IINN TTHHEE MMIIRRDDIITTAA OOPPHHIIOOLLIITTEE ZZOONNEE ((AALLBBAANNIIAA))

Hans-Jürgen Gawlick1, Wolfgang Frisch2, Lirim Hoxha3,Paulian Dumitrica4, Leopold Krystyn5, Richard Lein5, Sigrid Missoni1, and Felix Schlagintweit1

1 University of Leoben, Department for Applied Geosciences and Geophysics: Prospection and Applied Sedimentology,Peter-Tunner-Str. 5, 8700 Leoben, Austria

2 University of Tübingen, Institute of Geosciences, Sigwartstrasse 10, 72076 Tübingen, Germany3 Geological Survey of Albania, Tirana, Albania4 Dennigkofenweg 33, 3073 Guemligen, Switzerland5 University of Vienna, Center for Earth Sciences, Althanstr. 14, 1090 Vienna, Austria

The Albanian ophiolites of the Mirdita Zone representremnants of Mesozoic oceanic lithosphere within the Di-naride-Hellenide segment of the Alpine orogenic system.They form a coherent, north-south trending belt and con-sist of a large variety of rocks attributed to originally com-plete ophiolitic sequences through oceanic uppermostmantle and crust. Most recent studies distinguish two different rock associations forming the Western (WOB)and Eastern Ophiolite Belt (EOB). Both are thought to de-rive from a narrow Jurassic ocean between Apulia in thewest and the Korabi-Pelagonian microcontinent to theeast called Pindos-Mirdita Ocean.

Creation of oceanic crust in the Pindos-Mirdita Ocean isinferred to have started around the Early/Middle Jurassicboundary followed by intra-oceanic subduction in LateJurassic times. The age of the ocean seemed to be proven byradiolarians from sediments associated with basaltic anddacitic lavas which gave Late Bajocian to Early Callovianand Middle Callovian to Late Oxfordian ages, respectively.The ophiolite suite is closely associated with radiolarites andophiolitic mélanges containing blocks of up to kilometer-size. Blocks of Triassic radiolarites in the mélanges were interpreted to have been derived from the continental mar-gins surrounding this short-lived Jurassic ocean. Mélangeformation is generally considered to have taken place dur-ing post-sedimentary thrusting in Tithonian time.

The Mirdita Ophiolite Zone in Albania is associatedwith widespread mélanges containing components of upto nappe-size. We dated matrix and components of themélange by radiolarians, conodonts, and other taxa. Thecomponents consist of radiolarites (equivalent to Meliatafacies), pelagic limestones (different Hallstatt facies block– grey and red Hallstatt facies) and shallow-water lime-stones (Dachstein limestone facies), all of Triassic age, aswell as ophiolites. Triassic radiolarite as a primary cover ofophiolite material proves Middle Triassic onset of Mirdita

ocean-floor formation. The mélange contains a turbiditicradiolarite-rich matrix („radiolaritic flysch“), dated as LateBajocian to Early Oxfordian. It formed as a synorogenicsediment during west-directed thrusting of ophiolite andsediment-cover nappes representing ocean floor and un-derplated fragments of the western continental margin.The tectonic structures formed during these orogenicevents („Younger Kimmeridgian or Eohellenic Orogeny“)are sealed by Late Jurassic platform carbonates (equiva-lent to the Plassen carbonate platform in the NorthernCalcareous Alps).

From the scenario we see no evidence for an indepen-dent Pindos-Mirdita Ocean. An in-situ position of theMirdita ophiolites would mean that the Triassic passivecontinental margin with its typical facies arrangementfrom the pelagic outer shelf (Hallstatt limestone facies)towards the inner shelf with its reefal and lagoonal carbonates (Dachstein limestone facies, Hauptdolomitefacies) would have been disrupted by an ocean. Remnantsof the passive-margin sequences are found both to thewest and the east of the present Mirdita Zone. Thereforewe conclude that the Mirdita-Pindos Ophiolite Zone is nomore in its original position relative to the geologic unitsto its east and west but must be a far-travelled part of theNeotethys Ocean (Vardar segment), brought into its pre-sent position by west-directed far-distance thrustingfrom the Vardar Zone. In the Northern Calcareous Alps thesituation is the same in a number of particulars, althoughthe in Late Jurassic times obducted ophiolite units are notpreserved but only indicated in detrital material of theKimmeridgian to Tithonian radiolaritic wildflysch.

The geological history conforms with that of the InnerDinarides and adjoining areas; we therefore correlate theMirdita-Pindos Ophiolite Zone with the Vardar Zone andexplain its present position by far-distance west-directedthrusting.

Geo.Alp, Vol. 4, 200748


AA CCOOMMPPAARRIISSOONN OOFF TTHHEE LLAATTEE TTRRIIAASSSSIICC TTOO EEAARRLLIIEESSTT CCRREETTAACCEEOOUUSSSSEEDDIIMMEENNTTAARRYY SSUUCCCCEESSSSIIOONNSS AANNDD TTHHEE TTEECCTTOONNOOSSTTRRAATTIIGGRRAAPPHHIICC EEVVOOLLUUTTIIOONN OOFF TTHHEE IINNTTEERRNNAALL

ZZOONNEESS OOFF TTHHEE BBEETTIICC CCOORRDDIILLLLEERRAA ((SSPPAAIINN)) AANNDD OOFF TTHHEE NNOORRTTHHEERRNN CCAALLCCAARREEOOUUSS AALLPPSS ((AAUUSSTTRRIIAA))::PPAALLAAEEOOGGEEOOGGRRAAPPHHIICC IIMMPPLLIICCAATTIIOONNSS

Hans-Jürgen Gawlick1, Agustin Martín-Algarra2, Sigrid Missoni1, and Luis O’Dogherty3

1 University of Leoben, Department for Applied Geosciences and Geophysics: Chair of Prospection and Applied Sedimentology,Peter-Tunner-Str. 5, A-8700 Leoben

2 Universidad de Granada, Departamento de Estratigrafia y Paleontologia, Facultad de Ciencias, Campus Universitario deFuentenueva, ES-18071 Granada

3 Universidad de Cádiz, Facultad de Ciencias del Mar y Ambientales: Ciencias de la Tierra, Campus del Río San Pedro s/n,ES-11510 Puerto Real

A comparative study of stratigraphy, facies and paleo-geography of the Northern Calcareous Alps (Eastern Alps;Austria, Germany) and of the Internal Zones of the BeticCordillera (Spain) shows that both regions are very similarin facies development, sedimentary and tectonostrati-graphic evolution from the Late Triassic to the earliestCretaceous. We present some characteristic examples ofidentical sedimentary successions formed under similargeodynamic conditions.

A widespread Late Triassic shallow water carbonateplatform development occurred in the Internal Zones ofthe Betic Cordillera, producing carbonate sediments withfacies similar to those of the well known Hauptdolomit-Dachstein carbonate platform of the Northern CalcareousAlps.

The shallow water carbonate production suddenlyended in both regions around the Triassic/Jurassic bound-ary, and was associated with the onset of hemipelagic car-bonate sedimentation in both areas, except in theMalaguide Domain. This drowning event was additionallymarked by fault scarp breccia formation in the InternalZones of the Betic Cordillera, and block tilting in theNorthern Calcareous Alps, due to the starting rifting ofthe future Penninic-Piedmont Ocean.

The occurrence of the first oceanic crust in the Pen-ninic-Piedmont and Nevadofilabride Realms during LatePliensbachian-Toarcian times was coeval to the formationof continental margins with a horst and graben topogra-phy in their southeastern parts, both in the Eastern Alps

and in the Internal Domain of the Betic Cordillera. Thiswas contemporaneous with a deepening event and basinstarvation that produced reduced and condensed pelagicsuccessions during the late Early to Midde Jurassic in bothregions.

A widespread radiolaritic sedimentation during theBathonian coincides with the final break-up and spread-ing of oceanic crust in the Penninic-Piedmont Ocean, andwas followed by pelagic carbonate and radiolaritic sedi-mentation up to the earliest Cretaceous.

To conclude, the Internal Domains of the BeticCordillera represent, during the Late Triassic to Berriasian,a western prolongation of the Austroalpine Domain.Therefore, the Internal Domains of the Betic Cordillera, aswell as their Austroalpine counterparts, form the internalsoutheastern margin of the Penninic-Piedmont Ocean incontrast to its northwestern margin which was formed bythe South Iberian Paleomargin, corresponding to the Pre-betic and Subbetic external domains of the BeticCordillera, and by the South European Paleomargin whichcorresponds to the Helvetic-Ultrahelvetic domains of theAlps.

Both areas were connected from the Triassic until theearliest Cretaceous and were not separated by an oceanicdomain, as partly reconstructed.

A comparative study in the framework: Acciones-In-tegradas Austria-Spain (ÖAD, Ministerio de Cienca y Tec-nologia).

Geo.Alp, Vol. 4, 2007 49


KKLL--SSPPEEKKTTRROOSSKKOOPPIISSCCHHEE UUNNTTEERRSSUUCCHHUUNNGGEENN AANN KKLLUUFFTTGGEEBBUUNNDDEENNEENN FFLLUUOORRIITTEENN VVOONNSSAABBKKHHAADDOOLLOOMMIITTEENN HHYYDDRRAASS UUNNDD KKRRIISSTTAALLLLIINNGGEESSTTEEIINNEENN DDEESS MMIITTTTLLEERREENN SSCCHHAARRZZWWAALLDDEESS

Axel Gillhaus, Thomas Götte und Detlev K. Richter

Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität Bochum

Fluorite (CaF2) treten als späte Mineralisationen(50–1500 µm) in Klüften der faziesgebundenen frühdia-genetischen Dolomite Hydras (Oberperm und Obertrias)auf (Gillhaus 2000). Die makroskopisch farblosen Kristallehaben in beiden Formationen eine leuchtend blaue Lumi-neszenzfarbe ohne Zonarbau und zeichnen sich KL-spek-troskopisch durch Eu2+-Dominanz bei untergeordnetemAuftreten von Dy3+ aus.

Die hydrothermalen Fluorite aus Gängen in Kristallin-gesteinen des mittleren Schwarzwaldes sind makrosko-pisch farblos, grünlich oder blau und nach Werner & Den-nert (2004) einer Fluorit-Hauptphase und bis zu drei wei-teren Mineralisationsphasen mit Fluorit zuzuordnen.Nach KL-spektroskopischen Untersuchungen sind dieseFluorite reich an Selten Erden Elementen (SEE) und bildendrei Gruppen:1. Blau lumineszierende Fluorite mit Eu2+-Dominanz und

wenig anderen SEE2. Graugrünlich bis olivfarben lumineszierende Fluorite

mit wenig Eu2+ und dominanten Peaks von Dy3+, Sm3+

und Tb3+.3. Blaugrün bis blauviolett lumineszierende Fluorite, in

deren KL-Spektren intensive Peaks sowohl von Eu2+ als

auch von den dreiwertigen SEE Dy3+, Sm3+ und Tb3+

ausgebildet sind. Die Beschränkung der Fluorite Hydras an Klüfte in

frühdiagenetischen Dolomitserien unterstreicht hinsicht-lich ihrer Genese eine Laugung aus dem Nebengestein,während die komplexe Abfolge und Zusammensetzungder Fluoritmineralisationen des mittleren Schwarzwaldesdurch eine Zufuhr von Lösungen mit variablen Zusam-mensetzungen aus größeren Tiefen sowie Umkristallisa-tionen jeweils älterer Fluoritphasen zu erklären ist.

Gillhaus, A. (2000): Petrographisch/geochemische Unter-suchungen zur Genese und Diagenese der Dolomitevon Hydra unter besonderer Berücksichtigung der Ka-thodolumineszenzspektroskopie. – Bochumer geol.und geotechn. Arb., 54, 123 S., Bochum.

Werner, W. & Dennert, V. (2004): Lagerstätten und Berg-bau im Schwarzwald. – 334 S., Freiburg (Landesamt fürGeologie, Rohstoffe und Bergbau Baden-Württem-berg).

Geo.Alp, Vol. 4, 200750


KKYYAANNIITTEESS FFRROOMM MMIIOOCCEENNEE ((OOSSMM)) SSAANNDDSS OOFF TTHHEE GGRRAAUUPPEENNSSAANNDDRRIINNNNEE AANNDD TTHHEEAALLPPIINNEE FFOORREELLAANNDD:: AA VVAALLLLEEYY--FFIILLLL SSTTUUDDYY BBYY MMEEAANNSS OOFF CCAATTHHOODDOOLLUUMMIINNEESSCCEENNCCEE AANNAALLYYTTIICCSS

Peter Görgen and Detlev K. Richter

Ruhr-Universität Bochum, Institut für Geologie, Mineralogie und Geophysik, Universitätsstr. 150, 44801 Bochum

The Miocene Graupensandrinne is a small, elongated,fluvial sediment structure, which extended along thenorthern rim of the foreland basin as a palaeo-valley(Buchner, 1996). It consists of poorly sorted sands to fine-gravels. The material is expected to be debris of the base-ment rocks from the Bavarian-Bohemian-Massive.

Directions of deposition of the Graupensandrinne aswell as of the Alpine foreland were compared in a CL-pilot study, illustrated by the mineral kyanite. The miner-al luminescense occur in two known colours: red andblue (Marshall, 1988). In the CL-spectra of the examinedkyanites intrinsic bands appear at 420 nm and 500 nm.Beside the intrinsic bands, there are two characteristicnarrow bands at 688,5 nm and 705,2 nm emerging froma broad band. These are the emission lines of the 3d3-transition within a Cr3+-center, which is commonlyknown from other minerals (e.g. topaz, corundum) (Gaftet al., 2005). Kyanites with a red luminescence exclusive-ly show the two characteristic Cr-bands. Blue lumines-cent kyanites however show more strongly developedintensities within the range of short-wave radiation, butthe appearance of the characteristic Cr-bands is likewisepossible. Occurrence and distribution of the red and blueCL-characteristics permit a CL-classification of kyanitein four maintypes as well as in five and two subtypes, respectively (Görgen et al., 2006). For this study the CL-classification was reduced to three maintypes: I – kyan-ites with a red luminescence, II – kyanites with a blue lu-minescence, III – kyanites with red and blue lumines-cence.

This study proves that the kyanites from the Graupen-sandrinne between its north-eastern end at Kelheim andits south-western end at Riedern am Sand always show

the same composition. About 80% are exclusively red luminescent (type I) and about 20% are red and blue lumi-nescent (type III) kyanites, but no blue luminescent (typeII) ones occur. The same observation was made at host-rock material from the Bavarian-Bohemian-Massive. Incontrast, kyanites from the Alpine foreland south of theGraupensandrinne show all three types of luminescence.With some more than 90% red luminescent kyanites dominate the composition. The remaining percentage ofthe composition contains nearly equal amounts of blue aswell as red and blue luminescent kyanites. Material fromthe Kaunertal, Ötztal and Pitztal in the Alps show thesame composition. Therefore, it is improbable to expectAlpine material being a valley-fill of the Graupensan-drinne. In contrast, material from the Bavarian-Bohemi-an-Massive seems to be responsible for a valley-fill of theGraupensandrinne delivered through the palaeo-rivercourses of Main and Naab.

Buchner, E., Seyfried, H. & Hische, R (1996): Die Graupen-sande der süddeutschen Brackwassermolasse: ein In-cised Valley-Fill infolge des Ries-Impaktes. – Z. dt. geol.Ges., 114477//22, 169–181.

Marshall, D.J. (1988): Cathodoluminescence of geologicalmaterials. – 149 S.; Unwin-Hyman, Boston.

Gaft, M., Reisfeld, R. & Panczer, G. (2005): Luminescencespectroscopy of minerals and materials. – 356 S.;Springer, Berlin.

Görgen, P., Götte, T., Neuser, R.D. & Richter, D.K. (2006):KL-Schwermineralanalyse am Beispiel von Disthen. –Schriftenreihe der Deutschen Geologischen Gesell -schaft, 4455, 83, Hannover.

Geo.Alp, Vol. 4, 2007 51


SSEEDDIIMMEENNTTOOLLOOGGIICC AANNDD GGEEOOMMOORRPPHHOOLLOOGGIICC AANNAALLYYSSIISS OOFF TTHHEE EEVVOOLLUUTTIIOONNOOFF AALLLLUUVVIIAALL FFAANNSS IINN TTHHEE SSOOUUTTHHEERRNN DDEEAATTHH VVAALLLLEEYY,, CCAALLIIFFOORRNNIIAA ((SSWW--UUSSAA))

Matthias Greb1, Jörg Lang2, Nadja Fritschka2, Ulrich Bieg1,Jens Hornung1, Anke Friedrich3, Ronald Bruhn4, and Matthias Hinderer1

1 Technische Universität Darmstadt, Institut für Angewandte Geowissenschaften, Schnittspahnstr. 9, 64287 Darmstadt, Germany2 Leibniz Universität Hannover, Institut für Geologie und Paläontologie, Callinstr. 30, 30167 Hannover, Germany3 Ludwigs-Maximilians Universität München, Department für Geo- und Umweltwissenschaften, Luisenstr. 37,

80333 München, Germany4 University of Utah, Department of Geology and Geophysics, 135 South 1460 East, W. Browning Building, Salt Lake City,

United States of America

Alluvial fans are amongst the most complex and lessunderstood continental depositional environ ments. Littleis known about the evolution stages acting through time,undergoing changing external conditions. The aim of thisstudy is to gain new insights into the three-dimensionalcomposition of alluvial fan deposits. Special attention waspaid to the depositional processes and the correspondingarchitectural elements. Changing evolutionary stages(aggradation, pro- or retrogradation) have been inter-preted according to the concept of the morphometricbase-level.

The study was carried out on four alluvial fans (AnvilSpring Canyon Fan, Warm Spring Canyon Fan, HanaupahCanyon Fan & Trail Canyon Fan) along the eastside of thePanamint Range in the southern Death Valley NationalPark. Deeply incised channels made them ideal for sedimentological outcrop studies. The study combinessedimentological work at cut-faces of the incised channels with detailed geomorphologic surface-map-ping, supported by remote sensing data. At the cut-faces1D lithological profiles have been combined with 2Dphoto mosaics to transfer the lithological information toa quantitative analysis of architectural elements. These elements consist of at least one lithofacies type and arethemselves genetically bound to higher-order deposition-al systems such as braided-fluvial systems or mass flow

events. The aim of this analysis was to figure out thechange of predominant sedimentary processes. Decipher-ing the change of sediment supply and accommodationspace on alluvial fan deposits we also focused on erosionalfeatures (including reworking surfaces and the change ofthe width/depth distribution of scour pools) and aggrada-tional elements (e.g. longitudinal bars or spill-overs).Comparing the change of base-level between the differ-ent alluvial fans allowed us to discern an overall signal ofalluvial fan evolution.

Remote sensing data (Landsat 7 ETM+) have beenmerged with USGS ortho-quadrangle aerial photographsto create high resolution aerial maps. Enhanced by GPS-based geomorphological surface-mapping, it was possibleto identify several prominent surfaces as well as neo -tectonic movements, displayed in normal faults andstrike-slip features. These surfaces, differing in relativeage, were distinguished by their stage of soil development(Calcretes), development of desert varnish and desertpavement, their preservation potential of former incisionsand their neotectonic setting.

These approaches have been summarized to a compre-hensive model, identifying the return frequencies andmagnitudes of the most important formative processeslike debris flows and or braided-fluvial systems.

Geo.Alp, Vol. 4, 200752


MMIICCRROOFFAACCIIEESS,, BBIIOOSSTTRRAATTIIGGRRAAPPHHYY,, AANNDD GGEEOOCCHHEEMMIISSTTRRYYOOFF TTHHEE HHEEMMIIPPEELLAAGGIICC BBAARRRREEMMIIAANN--AAPPTTIIAANN IINN NNOORRTTHH--CCEENNTTRRAALL TTUUNNIISSIIAA::

IINNFFLLUUEENNCCEE OOFF TTHHEE OOAAEE 11aa OONN TTHHEE SSOOUUTTHHEERRNN TTEETTHHYYSS MMAARRGGIINN

Matthias Heldt, Martina Bachmann, and Jens Lehmann

University of Bremen, FB 5 – Geosciences, P.O. Box 330 440, D-28334 Bremen, Germany; [email protected]

Marine sediments of the Late Barremian-early LateAptian interval reflect significant changes of the Meso-zoic ocean/climate system, which coincide with severalmajor palaeoceanographic and palaeobiological events.An extraordinary high intraplate volcanism recorded inthe Pacific Ocean for the Early Aptian probably led to anintensified greenhouse effect by outgassing highamounts of carbon dioxide into the atmosphere. Especial-ly the late Early Aptian has been focussed by many authorsin last and recent years, due to an episode of increased or-ganic carbon burial (Oceanic Anoxic Event 1a). This 50 kato 1 ma lasting event is commonly expressed by an occur-rence of black shales in pelagic successions, associatedwith significant changes in marine flora and fauna and aglobal rise in sea-level. In addition, an episode of shallow-water carbonate-platform drowning, which coincides inthe initial part with the OAE 1a but lasts up to 4 my isrecorded especially from the northern and southwesternTethyan margin and from circum-Atlantic regions.

In this study, Upper Barremian-lower Upper Aptianhemipelagic deposits of the Hamada Formation in theDjebel Serdj area, north-central Tunisia were investigatedin detail on the base of microfacies, biostratigraphy, #13C

stratigraphy, and geochemistry. Our data provide an insight into the palaeoenvironmental evolution and sea-level fluctuations of the Tunisian shelf. The successionsconsist of mud-, wacke-, and packstones which reflectmid- and outer-ramp depositional environments. The deposits exhibit an unusually high thickness in the studiedarea. Within them, the Oceanic Anoxic Event 1a and carbonate-platform-drowning time-equivalent depositsare recognised on the base of planktic foraminifer- and#13C stratigraphy. The OAE 1a is characterised by a trans-gressive facies with high abundances of radiolarians andplanktic foraminifers, suggesting meso- to eutrophic nutritive values for the upper water column. Low diversitysmall benthic foraminifer assemblages suggest dysoxicconditions at the seafloor. Platform-drowning time-equivalent deposits, directly overlying the OAE1a arepartly showing a pronounced drop in carbonate content.Based on our microfacies studies, we subdivide the stud-ied sections into four genetic intervals: a pre-OAE 1a interval, an OAE 1a and platform-drowning-equivalentinterval, and a post-platform-drowning interval. We present a 3rd order sea-level curve for the Tunisian shelf,derived from the results of our microfacies studies.

Geo.Alp, Vol. 4, 2007 53


FFAACCIIEESS AANNAALLYYSSIISS OOFF TTHHEE LLAATTEE PPAALLEEOOZZOOIICC CCOOAARRSSEE--GGRRAAIINNEEDD CCLLAASSTTIICC DDEEPPOOSSIITTSS IINN TTHHEE CCEENNTTRRAALLEEUURROOPPEEAANN BBAASSIINN SSYYSSTTEEMM:: AANN EEXXAAMMPPLLEE FFRROOMM TTHHEE BBAARRNNIIMM BBAASSIINN ((BBRRAANNDDEENNBBUURRGG,, GGEERRMMAANNYY))

E. Kallmeier1, C. Breitkreuz1, and H. Kiersnowski2

1 TU Bergakademie Freiberg, Institut für Geologie, Bernhard-von-Cotta-Str. 2, 09599 Freiberg, Germany;[email protected]

2 Polish Geological Institute (PGI), Rakowiecka 4, PL-00-975 Warszawa, Poland

Under the aspect of a lithofacies classification of theLate Paleozoic coarse-clastic deposits (conglomerates andconglomeratic sandstones) of the Barnim Basin in Bran-denburg (Germany), five wells with more then 1300 m ofcore material were studied. The coarse-clastic sequencescan be grouped into older deposits which formed duringthe basin initiation under partial volcano-morphologicalcontrol, and into younger conglomerates the depositionof which was related to the early Late Rotliegend dynam-ics of the Southern Permian Basin (see also Gaitzsch1995).

As a result of the investigation, 16 lithofacies typesgrouped into six lithofacies associations have been differ-entiated. With special interest to the spatial and temporalevolution of the coarse clastic deposits, we could distin-guish two different types of alluvial fans (stream flowdominated “wet-type fans” and mass flow dominated“dry-type fans”), whose development was climatically aswell as tectonically controlled. Similar scenarios havebeen described for the Rotliegend sediments in the south-ern North Sea area by George & Berry (1993, 1997) and byHowell and Mountney (1997). Based on the recognition ofdrying upward cycles, for the Rotliegend evolution of theBarnim Basin, especially for its Grüneberg- and TuchenSub Basins, we assume a change from a mainlyclimatic/volcano-morphologic to a tectonic/climatic con-

trol. For most of the cycles, a correlation between theneighbouring sub basins was possible.

Gaitzsch, B., 1995: Grüneberg-Formation. – In Plein, E.,ed., Stratigraphie von Deutschland I: NorddeutschesRotliegendbecken, Rotliegend-Monographie Teil II:Cour. Forsch.-Institut Senckenberg, 183, p. 102–106.

George, G. T. & Berry, J. K. 1993: A new lithostratigraphyand depositional model for the Upper Rotliegend ofthe UK Sector of the Southern North Sea. – In North,C.P. and Prosser, D.J., eds, Characterization of Fluvialand Aeolian Reservoirs: Geol. Soc. Spec. Publs, no. 73, p.291–319.

George, G. T. & Berry, J. K. 1997: Permian (UpperRotliegend) synsedimentary tectonics, basin develop-ment and palaeogeography of the southern North Sea.– In Ziegler, K., Turner, P. and Daines, S.R., eds, Petrole-um Geology of the Southern North Sea: Future Poten-tial: Geol. Soc. Spec. Publ. 123, p. 31–61.

Howell, J. & Mountney, N., 1997: Climatic cyclicity and ac-commodation space in arid to semi-arid depositionalsystems: an example from the Rotliegend Group of theUK southern North Sea. – In Ziegler, K., Turner, P. andDaines, S.R., eds, Petroleum Geology of the SouthernNorth Sea: Future Potential: Geol. Soc. Spec. Publ. 123,p. 63–86.

Geo.Alp, Vol. 4, 200754


DDEERR SSTTEEIINNPPLLAATTTTEE--KKOOMMPPLLEEXX ((OOBBEERR--TTRRIIAASS,, NNÖÖRRDDLLIICCHHEE KKAALLKKAALLPPEENN,, ÖÖSSTTEERRRREEIICCHH)) ––RRÄÄUUMMLLIICCHHEE UUNNDD ZZEEIITTLLIICCHHEE EENNTTWWIICCKKLLUUNNGG EEIINNEESS KKAARRBBOONNAATTPPLLAATTTTFFOORRMMRRAANNDDEESS

Bernd Kaufmann und Werner E. Piller

Österreichische Akademie der Wissenschaften, Kommission für die paläontologische und stratigraphische Erforschung Österreichs,c/o Institut für Erdwissenschaften, Karl-Franzens-Universität Graz, Heinrichstrasse 26, 8010 Graz, Österreich;[email protected]

Während der späten Trias waren die Nördlichen Kalk -alpen Teil eines 500 km langen und 300 km breiten Schelfsam passiven Kontinentalrand der nordwestlichen Tethys.Die paläogeographische Position befand sich ca. 25-30°nördlich des Äquators. Tropische Bedingungen und niedri-ger Meeresspiegel bedingten das Wachstum gigantischer,bis 2000 m mächtiger Karbonatplattformen, die im Wesentlichen aus dem Hauptdolomit und dem Dachstein-kalk aufgebaut sind. Die südlichen und südwestlichen,ozean-seitigen Ränder dieses Dachstein-Karbonatschel-fes wurden von mächtigen Riffkarbonaten gesäumt, dieüber moderat geneigte Hänge in die pelagische Hallstatt-Fazies übergehen.

In spät-Norischer bis Rhätischer Zeit bedingten ver-stärkte Subsidenz und terrigener Eintrag vom Keuper-Hinterland die Entwicklung eines Intraschelf-Beckens(Kössener Schichten) im nördlichen Bereich des Karbonat-schelfs. Gleichzeitig bewirkte bessere Wasserzirkulationoffen-marinere Bedingungen auf der Karbonat-Platt-form, wodurch das Wachstum von Korallenkalkenbegüns tigt wurde. Bekannte Beispiele hierfür sind derSteinplatte-Komplex bei Waidring im GrenzgebietTirol/Salzburg und die Fleckenriffe von Adnet und der Rö-telwand bei Hallein. Diese gehören zu den ersten „moder-nen“ Riffkarbonaten der Erdgeschichte hinsichtlich derDominanz von Scleractiniern.

Der Steinplatte-Komplex ist ein außerordentlich gutaufgeschlossenes Beispiel eines Karbonatplattformran-

des. Tektonisch weitgehend ungestörte Aufschlüsse, Erhal tung der originalen Slope-Topographie und senk-rechte Aufschlusswände offenbaren einzigartige Einbli-cke in die räumliche und zeitliche Entwicklung eines Intra schelf becken-Karbonatplattform-Übergangs. Vor -an gehende Studien (Piller 1981, Stanton & Flügel 1989)konzentrierten sich auf die Paläontologie, Mikrofaziesund ökologische Zonierung der Rifforganismen. Detail-lierte stratigraphische, insbesondere sequenz-stratigra-phische Untersuchungen wurden dagegen bisher kaumunternommen.

Neue, hochauflösende und entzerrte Luftbilder (Or-thofotos) und ein digitales Geländehöhenmodell erlau-ben eine präzise Kartierung, geometrische Konstruktio-nen und genaue Korrelationen, die zusammen die Grund-lagen für eine detaillierte sequenz-stratigraphische Ana-lyse bilden. Besonderes Augenmerk liegt hierbei auf demEinfluß von Meeresspiegelschwankungen auf die Ent-wicklung des Karbonatplattformrandes des Steinplatte-Komplexes.

Piller, W.E. (1981): The Steinplatte Reef Complex, part ofan Upper Triassic Carbonate Platform near Salzburg,Austria. – SEPM Special Publication, v. 30, p. 261–290.

Stanton, R.J. & Flügel, E. (1989): Problems with Reef Mo-dels: The Late Triassic Steinplatte “Reef” (NorthernAlps, Salzburg/Tyrol, Austria). – Facies, v. 20, p. 1–138.

Geo.Alp, Vol. 4, 2007 55


SSEEDDIIMMEENNTTÄÄRREE GGÄÄNNGGEE DDEERR EEIISSEENNAACCHH--FFOORRMMAATTIIOONN ((OOBBEERRRROOTTLLIIEEGGEENNDDEESS)),,WWAARRTTBBUURRGGSSCCHHLLEEIIFFEE,, TTHHÜÜRRIINNGGEERR WWAALLDD

Eva König und Christoph Heubeck

Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstr. 74- 100, 12249 Berlin; [email protected]

Die klassischen Rotsedimentschüttungen der Eisenach-Formation (Oberrotliegendes; ca. 260 Ma) amnordöstlichen Beckenrand des spätvaristischen Werra-beckens im Thüringer Wald bestehen aus verzahntengrobkonglomeratischen „sheet flood“-Ablagerungen al-luvialer Fächer und laminierten siltig-tonigen lakustrinenPlaya-Ablagerungen. Wir beschreiben hier, nach unseremWissen erstmalig, zahlreiche sedimentäre Gänge am Geo-logischen Naturdenkmal der Parkplatzschleife der Wart-burg bei Eisenach. Mindestens drei der dort aufgeschlos-senen tonigen Siltsteinbänke zwischen den Konglomera-ten sind von ca. 20 subvertikalen, bis zu 80 cm langen, inder Regel sich leicht nach oben erweiternden Gängen undGangnetzen durchzogen. Die dominant mittelkörnigeKiesfüllung in einer tonigen Grobsandmatrix zeigt Merk-male von nach oben gerichteter, intrusiver Sedimentbe-wegung. Die charakteristische Geometrie von Trockenris-sen ist weder in Aufsicht noch in Querschnitt zu erkennen.

Die Gänge entstanden durch abruptes Übersteigen derZugfestigkeit der Siltsteine senkrecht zu ihrer Schichtungdurch Porenüberdruck in der unterliegenden Einheit, unmittelbar gefolgt von schneller, aufwärts gerichteter Sedimentinjektion in die sich nach oben hin öffnendenSpalten. Sediment wurde dabei entlang eines Druckgra-dienten aus den unverfestigten Geröllbänken injiziert,wobei die ungewöhnlich grobe Korngröße der Gangfül-lung auf eine zumindest anfänglich hohe Strömungsge-schwindigkeit der wässrigen Matrix, einen niedrigenKonsolidierungsgrad der einspeisenden Gerölleinheit und

damit einen ungewöhnlich hohen Porenüberdruck hin-weist. Morphologische Reste der an der Oberfläche ent-stehenden Sand- und Geröllvulkane („sand boils“) wurden von Lützner (1987) im wenige km entferntenStraßenanschnitt Wilhelmsthal dokumentiert; am Wart-burg-Parkplatz ist über den Gängen nur selten eine weni-ge cm hohe, konvex-aufwärts geformte Schichtung erkennbar. Bei Unterschreiten eines kritischen Druckgra-dienten und damit abnehmender Transportgeschwindig-keit verfüllten zuerst die gröbsten, später immer feinkör-nigere Korngrößen die Gänge.

Mechanismen zur Entstehung von Porenwassserüber-druck in den Konglomeratbänken der Eisenach Formationsind vorläufig nur schwer eingrenzbar. Hohe artesischeSpannung in den beckenwärts auskeilenden, in ihremOberlauf von Regen- und Abflusswasser gespeisten grob-klastischen Bänken mag zur periodischen Ruptur imper-meabler Abdeckschichten am Fuß der Fächer geführthaben. Dafür spricht das anscheinend weit verbreiteteVorkommen der sedimentären Gänge in zahlreichen Bän-ken und ihr Auftreten in nichtlinearen „Clustern“ vorwie-gend am Übergang zwischen grob- und feinklastischerFazies. Alternativ kann Porenwasserüberdruck auch durchzyklisches „seismisches Pumpen“ während Erdbeben inden tektonisch aktiven, von zahlreichen Randstörungenbegrenzten Oberrotliegendbecken Mitteldeutschlandsentstanden sein. Eine detaillierte Kartierung der stratigra-phischen Verbreitung der sedimentären Gänge könntediese Hypothesen möglicherweise eingrenzen.

Geo.Alp, Vol. 4, 200756


CCHHEEMMOOSSTTRRAATTIIGGRRAAPPHHYY AANNDD PPAALLAAEEOOTTEEMMPPEERRAATTUURREE EEVVOOLLUUTTIIOONNAACCRROOSSSS TTHHEE TTRRIIAASSSSIICC--JJUURRAASSSSIICC BBOOUUNNDDAARRYY

Christoph Korte1,2, Stephen P. Hesselbo2, Heinz W. Kozur3, and Hugh C. Jenkyns2

1 Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstr. 74-100, 12249 Berlin, Germany2 Department of Earth Sciences, University of Oxford, Parks Road, Oxford, OX1 3PR, United Kingdom3 Rézsü u. 83, H-1029 Budapest, Hungary

Carbon-isotope trends are useful tools for strati -graphic correlation, especially during times of major per-turbation to the carbon cycle. For the Triassic-Jurassicboundary major perturbations have been documented,but carbon-isotope data only exist for bulk rocks. We haveproduced carbon and oxygen isotope values from well-preserved oysters with low-magnesium calcite shells thatare relatively resistant to diagenetic alterations. Thesedata are generated from Lavernock Point, a section closelyadjacent to a candidate stratotype for the base of theJurassic, at St Audrie’s Bay (UK). The carbon isotope signa-ture from St Audrie’s Bay, previously defined on the basisof bulk organic matter analysis, is confirmed by our newdata. We also have analysed bulk carbonate samples fromCs� vár-quarry (Hungary), Kendelbachgraben (Austria),

and Lime Regis (UK). These data sets, taken together, illus-trate detailed features of the carbon isotope curve includ-ing: (1) the initial negative isotope excursion; (2) a pro-nounced positive excursion, and; (3) an extended mainnegative isotope excursion. Palaeotemperatures calculat-ed from oxygen-isotope values from Lavernock Point oysters are relatively cool (9 to 15 degrees C) at the begin-ning of the positive carbon-isotope excursion, and shift to relatively warm values (20 to 27 degrees C) during themain negative carbon-isotope excursion. Our results arecompatible with the idea that positive carbon isotope excursions correspond to times of low atmospheric carbon dioxide content, and negative carbon-isotope ex-cursions correspond to times of high atmospheric carbondioxide content.

Geo.Alp, Vol. 4, 2007 57


AA LLAATTEE MMIIOOCCEENNEE CCLLIIMMAATTEE HHIISSTTOORRYY –– IINNSSIIGGHHTTSS BBAASSEEDD OONN NNEEWW PPRROOXXIIEESS

Karsten F. Kroeger1, Thomas C. Brachert2, and Markus Reuter3

1 GeoForschungZentrum Potsdam, Telegrafenberg, 14473 Potsdam; [email protected] Johannes Gutenberg Universität Mainz, Becherweg 21, 55099 Mainz3 Karl-Franzens-Universität Graz, Institut für Erdwissenschaften, Bereich Geologie und Paläontologie, Heinrichstr. 26, A-8010 Graz

Major events and trends in Cenozoic climate are wellknown from deep sea stable isotope records. Knowledge ofsurface conditions has been continuously increased in thepast years but in many cases remains ambiguous due to thesusceptibility of planktonic organisms to diagenesis on onehand and limited age resolution in shallow water sedi-ments on the other. The present study introduces an ap-proach which is independent from stable isotope data, in-tegrating a refined chronostratigraphic method using highresolution Sr Isotope stratigraphy and coralline red algaeas climate (water depth and temperature) indicators.

A well preserved and for shallow water deposits rela-tively continuous succession of Tortonian limestones richin coralline red algae allowed us to apply both methodsand to reconstruct a detailed climate history. Up to 100 mthick Tortonian deposits crop out in a 50 km2 wide areaaround the city of Matala. The exceptional outcrop condi-tion allowed reconstructing the stratal architecture. Ver-tical changes in lithology and biotic elements are verysimilar in the entire area and are interpreted to reflectchange in climate and sea level.

The stratigraphy of Tortonian sediments was estab-lished using 87Sr/86Sr of pectinid shells which werescreened carefully for possible diagenetic alteration duringanalysis. In contrast to the common approach to infer agesby plotting Sr isotope ratios on a smoothed reference curvewe employed unsmoothed Sr isotope curves for reference.In contrast to the common method, which due to the shortterm fluctuation in seawater Sr isotope ratios has a largeuncertainty in resulting ages, this approach uses the fluc-tuation in seawater Sr isotope that are found both in thereference curve and in the measured dataset as an addi-tional information as outlined in Kroeger et al. (2007). Srisotope curves show remarkable similarities to Atlantic#18O. It thus becomes apparent that fluctuations in Sr iso-tope ratios also relate to glaciation-deglaciation processesas has been hypothesized by various authors (e.g. Zachos etal. 1999) and therefore to eustasy. Such a relationship issupported by the detection of 400 kyr cyclicities in Torton-ian 87Sr/86Sr records (Sprovieri et al., 2004). Therefore wepropose that Sr isotope stratigraphy can also be used as anadditional proxy for climate change.

Paleoenvironmental studies on Tortonian limestoneswere carried out by analyzing coralline red algal assem-blages. Coralline red algae are susceptible to both, tem-perature and light intensity and therefore to waterdepth. By establishing relative abundances of corallinered algal associations it is possible to define ranges oftemperature and water depth. Results for the studiedlimestone succession on Crete indicate fluctuation be-tween warm temperate and tropical climatic conditions.As indicated by growth band measurements on Poritescorals, mean winter seawater surface temperatures(MWSSTs) during tropical intervals are between 20 and21°C. Minimum temperatures inferred from coralline redalgae are around 14–16°C. This indicates a temperaturevariation of 4–7°C during the Tortonian. A conspicuoustemperature minimum occurs around 9,4 Ma which co-incides with a discontinuity surface with a wide regionalextent, interpreted as an eustatic lowstand (Kroeger etal. 2007). This interval is also characterized by a mini-mum in 87Sr/86Sr and a maximum in #18O. Between 8 and9 Ma, on the other hand the integrated data suggest sta-ble tropical conditions and little northern hemisphereglaciation.

Kroeger, K.F., Reuter, M., Forst, M.H., Breisig, S., Hartmann,G. & Brachert, T.C., 2007, Eustasy and seawater Sr composition: application to high-resolution Sr- isotope stratigraphy of Miocene shallow-water car-bonates. – Sedimentology. doi: 10.1111/j.1365-3091.2006.00849.x.

Sprovieri, M., Bonanno, A., Barbieri, M., Bellanca, A., Patti,B. & Mazzola, S., 2004, 87Sr/86Sr variation in TortonianMediterranean sediments: a record of Milankovitchcyclicity, in D’Argenio, B., Fischer, A.G., Premoli Silva, I.,Weissert, H., and Ferreri, V., eds., Cyclostratigraphy: ap-proaches and case histories. – SEPM Special Publica-tions v. 81, Tulsa, p. 17–26.

Zachos, J.C., Opdyke, B.N., Quinn, T.M., Jones, C.E. & Halli-day, A.N., 1999, Early Cenozoic glaciation, antarcticweathering, and seawater 87Sr/86Sr: Is there a link? –Chemical Geology, v. 161, p. 165–180.

Geo.Alp, Vol. 4, 200758


TTHHEE AANNIISSIIAANN SSEECCTTIIOONN OOFF KKÜÜHHWWIIEESSEENNKKOOPPFF//MMOONNTTEE PPRRÀÀ DDEELLLLAA VVAACCCCAA ((DDOOLLOOMMIITTEESS,, NN--IITTAALLYY))::IINNTTEEGGRRAATTEEDD BBIIOOSSTTRRAATTIIGGRRAAPPHHIICC,, PPAALLEEOOCCLLIIMMAATTIICC AANNDD PPAALLEEOOEENNVVIIRROONNMMEENNTTAALL SSTTUUDDIIEESS

Evelyn Kustatscher1, Guido Roghi2, Paolo Mietto2, and Johanna H.A. van Konijnenburg-van Cittert3

1 Naturmuseum Südtirol / Museum of Nature South Tyrol, 39100 Bozen, Italy2 Department of Geology, Paleontology and Geophysics, Univ. Padova and CNR, 35100 Padova, Italy3 Laboratory of Palaeobotany and Palynology, Budapestlaan 4, 3584 CD Utrecht, the Netherlands

The discovery of a rich plant deposit at Kühwiesenkopf/Monte Prà della Vacca (Prags/Braies, N-Italy) gave rise tointegrated biostratigrafic, palaeoclimatic and palaeoenvi-ronmental studies of this area, based mainly on stratigra-phy, ammonoids and palynomorphs. The 200 m thickstratigraphical sequence belongs to the Dont Formationtraditionally considered Pelsonian-Illyrian in age.

Ammonoids collected from the section attribute it to atime interval related at least from the middle Pelsonian(Balatonicus Subzone of Mietto and Manfrin, 1995) to thelower Illyrian. The expanded stratigraphic section permit-ted also to identify three different palynological assem-blages and to calibrate them with ammonoids collectedfrom other important stratigraphic sections (Dont and M.Rite). Comparisons with local biostratigraphical scales,refers the section to the middle-upper Pelsonian follow-ing Brugman (1986) or to the middle Pelsonian – lower Il-lyrian considering Kustatscher & Roghi (2006) and Kus-tatscher et al (2006).

For quantitative analysis up to 300 palynomorphs havebeen counted per sample on a total of 84 samples. The results have been applied to several methods known fromthe literature. Following the procedure outlined by Viss-cher & Van der Zwan (1981) a general dominance of thehygrophytic taxa becomes evident. This indication sug-gests a local warm and humid climate confirmed by thedominance of the “wetter” Lowland SEG taxa using Ab-bink’s method (1998). However, throughout the sectionsome oscillations in the palynological composition become visible, also at short time intervals. The cause ofthese variations could be either due to variations of the

climate conditions and/or sea-level fluctuations. Palyno-facies analysis indicates a deposition of the organic mate-rial in a marginal and shallow environment with shorttransportation. Since the stratigraphical indications ofthe formation suggest a basinal depositional environmentfor the section, the organic material could have been deposited in more basinal conditions.

Abbink, O.A., 1998: Palynological identification in theJurassic of the North sea region. – PhD-tesis, Utrecht.

Brugman, W.A., 1986: A palynological characterizationof the Upper Scythian and Anisian of the Transdanu-bian Central Range (Hungary) and the VicentinianAlps (Italy). PhD thesis, Utrecht.

Mietto, P. & Manfrin, S., 1995: A high resolution MiddleTriassic ammonoid standard scale in the TethysRealm. A preliminary report. Boll. Soc. Géol. Fr. 166(5), 539-563.

Kustatscher, E. & Roghi, G., 2006: Anisian palynomorphsfrom the Dont Formation of Kühwiesenkopf / MontePrà della Vacca section (Braies Dolomites, Italy). – Mi-cropalaeontology, 52 (3): 223-244.

Kustatscher E., Manfrin S., Mietto P., Posenato R. &Roghi G., 2006: New biostratigraphic data on Anisian(Middle Triassic) palynomorphs from the Dolomites(Italy). – Rev. Palaeobot. Palyn., 140: 79–90.

Visscher, H. & Van der Zwan, C.J., 1981: Palynology of thecircum-Mediterranean Triassic: phytogeographicaland palaeoclimatological implications. – Geol. Rund-sch., 70(1-2): 625-634.

Geo.Alp, Vol. 4, 2007 59


UUNNTTEERRSSUUCCHHUUNNGGEENN AANN BBRROONNZZEE-- UUNNDD EEIISSEENNZZEEIITTLLIICCHHEENN AABBLLAAGGEERRUUNNGGEENNVVOONN MMAASSSSEENNBBEEWWEEGGUUNNGGEENN IINN EEIINNEEMM PPRRÄÄHHIISSTTOORRIISSCCHHEENN SSAALLZZAABBBBAAUU IINN HHAALLLLSSTTAATTTT

((SSAALLZZKKAAMMMMEERRGGUUTT,, ÖÖSSTTEERRRREEIICCHH))

Stefanie Lang1, Natascha Rumpler1, Dominik Ehret1, Stefan Götz1, Hans Reschreiter2 und Joachim Rohn3

1 Geologisches Institut, Universität (TH) Karlsruhe, Kaiserstr. 12, D-76128 Karlsruhe2 Prähistorische Abteilung, Naturhistorisches Museum Wien, Burgring 7, A-1010 Wien3 Lehrstuhl für Angewandte Geologie, Universität Erlangen-Nürnberg, Schlossgarten 5, D-91054 Erlangen

Massenbewegungen (z.B. Felsstürze, Rutschungen,Erd- und Schuttströme) gehören seit jeher zu den gefähr-lichsten Naturkatastrophen. Heutzutage treten aktiveMassenbewegungen besonders in alpinen Gebieten aufund stellen oft eine große Gefahr für Mensch und Umweltdar. Während es zu aktiven oder rezenten Massenbewe-gungen zahlreiche Untersuchungen gibt, sind die Ablage-rungen reliktischer Massenbewegungen heute aufgrundvon Erosion und Verwitterung nicht mehr so leicht zuidentifizieren.

Hallstatt (Salkammergut, Österreich) ist für seine Salz-lagerstätten bekannt, die schon seit Tausenden von Jahreneine starke Anziehungskraft auf die Menschen dieser Re-gion ausüben. Dank spektakulärer archäologischer Fundekann der untertägige prähistorische Salzbergbau in Hall-statt bis in die Bronzezeit (ca. 1400 v. Chr.) zurückverfolgtwerden.

Aufgrund der ungünstigen geologischen und geotech-nischen Situation wurde das Hochtal von Hallstatt imLaufe der Jahrtausende immer wieder von Massenbewe-gungen heimgesucht, die verheerende Auswirkungen fürdie Menschen hatten. Mächtige mesozoische Karbonat-abfolgen liegen hier auf einer duktil-plastischen Unterla-ge aus permomesozoischen Evaporiten. Dadurch werden

große Bereiche dieses Gebietes von tiefgreifenden Mas-senbewegungen erfasst, die vor allem in Felsstürzen, Rut-schungen und Schuttströmen ihren Ausdruck finden.

Bei archäologischen Ausgrabungen wurden bis in eineTiefe von über 100 m mehrere prähistorische Abbauhallenund Schächte (Bronze- bis Eisenzeit, 1400–300 v. Chr.)entdeckt, die mit meterdicken, teilweise gradierten Abla-gerungen solcher Massenbewegungen verfüllt sind.Durch sedimentologische, (mikro-)fazielle und tonmine-ralogische Analysen dieses Übertagematerials lassen sicherste Erkenntnisse über die Herkunft des Materials und dieArt der Massenbewegung gewinnen. Dazu wurden ausdem Bergwerk an verschiedenen Stellen sowohl feinkör-nige als auch grobklastische Proben entnommen und ge-trennt ausgewertet. Das feinkörnige Material wurde einerKorngrößenanalyse und tonmineralogischen Analysenunterzogen. Die grobklastischen Proben wurden nachihrer Lithologie sortiert; dazu wurde der Rundungsgradund die Länge der mittleren Achse bestimmt.

Die Ergebnisse zeigen sowohl lithologische, als auchtonmineralogische Unterschiede der Klasten und desFeinmaterials. Daraus lassen sich zwei verschiedene Sze -narien zeichnen, die sich zu unterschiedlichen Zeiten imHochtal abgespielt haben könnten.

Geo.Alp, Vol. 4, 200760


RROOHHSSTTOOFFFFIINNTTEERREESSSSEENN UUNNDD IIHHRREE GGEEOOLLOOGGIISSCCHHEENN GGRRUUNNDDLLAAGGEENN IIMM RRHHÄÄTTIISSCCHHEENN DDAACCHHSSTTEEIINNKKAALLKKDDEESS SSTTEEIINNBBRRUUCCHHEESS SSTTAARRNNKKOOGGEELL,, BBAADD IISSCCHHLL,, OOBBEERRÖÖSSTTEERRRREEIICCHH,, ZZEEIITTRRAAUUMM 22000044––22000066

Manfred Leuprecht und Beatrix Moshammer

Geologische Bundesanstalt, Neulinggasse 38, 1030 Wien

Am Starnkogelsteinbruch und in der näheren Umge-bung sind sedimentologisch-mikrofazielle und tektoni-sche Untersuchungen im Gange, von denen wir vorerstfolgende interessante, teilweise aber noch weiterer Bear-beitung harrende Details präsentieren.

Der Vorzüge des Materials wegen wurde im Laufe derJahre der Abbau intensiviert, es kam mit Genehmigungneuer Überscharen zu laufender Steinbrucherweiterung,und dies gewährte, wenngleich aufgrund der komplexenLagerungsverhältnisse zwar durchaus noch nicht voll-ständige, so im Laufe der Zeit doch wesentlich bessere Ein-blicke. Verglichen mit MOSHAMMER (2004), sind nun-mehr neue Erkenntnisse speziell bezüglich Faziesverzah-nungen zwischen Dachsteinkalk und Kössener Schichtenangestrebt worden. Derartige fazielle Zusammenhängezwischen beiden sind wohl evident, aufgrund allgegen-wärtiger massiver tektonischer Einflüsse indes nichtimmer leicht mit eindeutigen Belegen zu versehen.

Wir gehen zunächst von einer nach Süden abtauchen-den Kössener Abfolge aus, in die aber geringmächtigerDachsteinkalk eingeschaltet scheint. Ob sedimentär oderaber tektonisch, konnte vorerst noch nicht eindeutig ge-klärt werden. Diese Kössener Fazies zeigt nach Süden hineine besonders auffällige schwarz vermergelte Entwick-lung und auf den Kalkbänken wellig-dickknollige Ober-flächen, alles mit vergleichsweise spärlichem, eingedell-tem Bestand an Brachiopoden und Muscheln. In kalkige-ren Anteilen konnten wir da und dort lebhafte Bioturbati-on feststellen.

Bereits tiefer und bis gegen Top der Abfolge tretenimmer wieder zu großen Stücken zerbrochene Korallen-stöcke (ehemals wahrscheinlich kleiner Riffkörper) auf.Sie scheinen von der jeweils nachfolgenden Vermergelungbegraben.

Über der geschilderten Kössener Abfolge folgt mächti-ger Dachsteinkalk. Durch SE-NW-Einengung kam es zurAusbildung einer SSW-fallenden Mulden-Sattel-Strukturund nachfolgend zu sinistralen NE-SW gerichteten Zer-scherungen, sowohl zwischen Sattel und Mulde als auchdes Muldenkerns. Im W-Bereich scheint die Verzahnung

DK-KÖSS erhalten, während für den östlichen Mulden -flügel der hohe tonige Anteil der KÖSS Gleitbahn und-mittel stellte, weshalb die Kössener Abfolge vollkommenüberschoben wurde.

Das Bildungsmilieu des Dachsteinkalkes wird als pho-tisch, flachmarin, subtidal, mit guter Strömung und Zirku-lation trübearmen, nährstoffreichen Wassers interpre-tiert. Durchströmter (riffnaher) Hinterriffbereich ein -schließlich lagunärer Bildung wird durch verschwemmteKorallen- und große Schwammreste sowie durch reicheForaminiferen- und Bryozoenfaunen und im lagunärenBereich durch auffallend großwüchsige Megalodontenund Gastropoden, nicht selten sogar eine ganze Muschel-bank in Lebensstellung, dokumentiert. Die Dachsteinkalk-bänke unterbrechen häufig grüne Tonlagen, 5 bis 10 cmstark, nach tektonischen Gleitvorgängen auch in etwasstärkeren Anschoppungen vorliegend. An den Kontaktenzeigen die Kalkbänke oft stylolithisierte Oberflächen,häufig sogar mit cm-tiefen Anlösungen, der Basalanteilder Kalkbank ist oft grünlich ausgeflasert. Unserer Mei-nung nach sind die meist türkisgrün gefärbten Zwi-schenlagen Residuate nach wiederholten tektonischenBewegungen und Drucklösungsvorgängen.

Für den aufgeschlossenen Dachsteinkalk-Kössener-Schichten-Komplex am Starnkogel sind dem Milieu nachkkeeiinnee LLooffeerrzzyykklleenn zu erwarten, und wir haben auch nir-gendwo Anzeichen davon bemerkt. Lithologie, Mikrofa-zies und Wechsellagerung mit den Kössener Schichten be-wirkten bei uns immer wieder Diskussionen zu der Frage,ob es sich hier tatsächlich um Dachsteinkalk handle oderaber eher bereits um (zumindest teilweise) dem soge-nannten „Rhätolias-Riffkalk“-Komplex zuzuordnendeAblagerungen.

Moshammer, B.: Rhätischer Dachsteinkalk und KössenerSchichten im Steinbruch Starnkogel, Bad Ischl,Oberösterreich. – Vortragskurzfassung der Poster -präsentation. – Ber. Inst. Erdwiss. K.-F.-Univ. Graz,Bd. 9., 284–285, Graz, 2004.

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LLOOWWEERR CCRREETTAACCEEOOUUSS AAMMMMOONNOOIIDDSS FFRROOMM TTHHEE DDOOLLOOMMIITTEESS ((SSOOUUTTHHEERRNN AALLPPSS,, IITTAALLYY))

Alexander Lukeneder

Natural History Museum, Geological-Palaeontological Department, Burgring 7, A-1010 Wien, Austria;[email protected]

Lower Cretaceous ammonoids (n = 424) were collectedat the Puez locality in the Dolomites of Southern Tyrol.The cephalopod fauna from the marly limestones to marlshere indicates Late Valanginian to Early Aptian age. Theunderlying Biancone Formation (Maiolica Formation) isEarly Valanginian, whereas the lowermost Rosso Ammonitico is of Jurassic to Berriasian age. The deposi-tion of the marly limestones and marls in this interval oc-curred during unstable conditions.

The ammonoid fauna comprises 27 different genera,each apparently represented by 1-2 species. The completeoccurrence at the Puez section is dominated by the Phyl-loceratina (30%) and the Ammonitina (34%). Phyl-lopachyceras (17%) and Phylloceras (13%) from the Phyl-loceratina are the most frequent components, followed byLytoceras (12%) from the Lytoceratina, and Barremites(10%) and Melchiorites (8%) from the Ammonitina. Phyl-loceatidae and Desmoceratidae are dominating thecephalopod-fauna.

Some ammonoid zones defined by Hoedemaeker et al.(2003) can be recognized. The following index fossils wereexamined within the collections of the NHMW (Austria)and the NMB (Italy): for the uppermost ValanginanCriosarasinella furcillata (C. furcillate Zone and Subzone),for the middle Lower Hauterivian Olcostephanus (Jeanno-ticeras) jeannoti (O.(J.) jeannoti Subzone) and for the mid-dle Lower Hauterivian Olcostephanus (Jeannoticeras)jeannoti (O. (J.) jeannoti Subzone) and Heinzia sayni forthe lowermost Upper Barremian (H. sayni Subzone; Reboulet and Hoedemaeker (reporters) et al., submitted).

The ammonoid fauna contains only descendants of theMediterranean Province (Tethyan Realm). Most affinitiesof the cephalopod fauna are observed with faunas fromthe adjacent areas of Italy (Lessini Mountains, Belluno,southern Trento Plateau), the Northern Calcareous Alpsand the Bakony, Geresce and Mecsek Mountains of Hun-gary. This is explained by the neighbouring position of thelatter areas during the Early Cretaceous on theApulian/Adria block and the Alpine-Carpathian micro -plate.

The frequency of the ammonoids and the richness ofthe fauna make this section especially suited to accuratelystudy the vertical ammonite distribution. The main focusin the future will be to investigate in detail the strati-graphic framework of the Puez section. Bed-by-bed collecting is required to obtain crucial data on the am-monoid distribution and occurrence (range). A coopera-tive project with this aim is planned by the Natural HistoryMuseum in Vienna and the Southern Tyrol “Natur Museum” in Bozen.

A further study on the the palaeoecology and synecol-ogy of the cephalopod fauna of the Puez section is currently under preparation by Alexander Lukeneder. Itfocuses on the autecological features exhibited by differ-ent fossil groups (annelids, bryozoans, foraminifera,corals) on ammonoid shells, which act as cryptic habitatsfor different encrusters in the Lower Cretaceous of thePuez locality.

Geo.Alp, Vol. 4, 200762


LLOOWWEERR CCRREETTAACCEEOOUUSS AAMMMMOONNOOIIDDSS AASS IISSLLAANNDDSS FFOORR CCOORRAALLSS((DDOOLLOOMMIITTEESS,, SSOOUUTTHHEERRNN AALLPPSS,, IITTAALLYY))

Alexander Lukeneder

Natural History Museum, Geological-Palaeontological Department, Burgring 7, A-1010 Wien, Austria;[email protected]

Early Cretaceous ammonoids (424) represent almostthe totality of the macrofauna (85 %) at the Puez localityin the Dolomites of Southern Tyrol. The cephalopod faunafrom the marly limestones to marls here indicates LateValanginian to Early Aptian age. The ammonoids are wellpreserved (mostly in concretions) and appear assteinkerns without shell. The very abundant and general-ly wellpreserved assemblage consists of 27 genera: fromphylloceratids Phylloceras, Phyllopachyceras, from lyto-ceratids Lytoceras, Eulytoceras, Protetragonites, Leptote-tragonites; from ammonitids Neolissoceras, Barremites,Melchiorites, Abrytusites, Neocomites, Criosarasinella,Kilia nella, Olco stephanus, Silesites, Jeanthieuloyites,Heinzia, Discoidellia, Acanthodiscus and from the ancy-loceratids Pseudo thurmannia, Macroscaphites, Dis-similites, Acrioceras, Crio ceratites, Anahamulina, Hamu -lina, Ancylo ceras. The ammonoid fauna contains only de-scendants of the Mediterranean Province (TethyanRealm).

The extraordinarily rich invertebrate fauna consists ofammonoids, ammonoid jaws (aptychi), coleoids, bivalves,brachiopods, serpulids, sea urchins, ophiurids, corals, ben-thic/planktonic foraminifera and radiolarians. The benthicmacrofossils observed in the ammonoid beds comprise bi-valves, brachiopods and, surprisingly, corals. Huge numberof encrusting species like serpulids and corals were examined.

The most exciting feature of the fauna is the fact thatsolitary corals of Cycloseris sp. lived on ammonoid shellsduring the Early Cretaceous of the Dolomites. This is notknown from other sediments and localities through timeand space. The relation between the latter fossil groups isreported for the first time from the Early Cretaceous.

In most cases only the round bottom plate of the coralsis visible attached to the steinkerns of the ammonoids.Only rare specimens (2) show three-dimensional preserva-

tion of the coral body with its septa. All kinds of am-monoids are attached with relics of solitary corals: lyto-ceratids, phylloceratids, ammonitids and ancyloceratids,ribbed species as well as smooth species. Therefore a secondary hard ground is needed for settling. The hardsubstrate must have been available for the epibionts overa quite long time so that they had enough time to settleand grow.

The morphology is similar to that of Upper Cretaceoussolitary corals like Connolites or Micrabacia. Bottom discsare from 2 mm up to 4 cm in diameter. Internal structures,septa and composition, are comparable with the latterspecies. Despite these similar features it is not known fromcorals like Connolites or Micrabacia that they could havelived on ammonoid shells or even ‘normal’ hardgrounds.Serial thin sections were made and show remarkable dif-ferences from other known solitary corals. The describedsolitary corals needed some time to grow up to a maximalsize of 4 cm in diameter. This shows that corals and otherencrusters had enough time to overgrow the differentshells. The number of about 20 corals attached on ammonoid shells shows that this is common at the Puezlocality. A single ammonoid shell could be attached by upto 6 corals on it.

The main focus of future studies of the Puez area willbe on the palaeoecology, stratigraphy and synecology ofthe cephalopod fauna of the Puez section.

A joint integrative high resolution project is plannedbetween the Natural History Museum in Vienna and the“Natur Museum” in Bozen.

The multitasking background contains investigationon fields of macro- and microfossils, isotopes, litho-,cyclo-, magneto-and biostratigraphy as tools for investi-gating the Lower Cretaceous within the Dolomites. Theambition is to establish the Puez Area as a new key regionof the Tethyan Realm.

Geo.Alp, Vol. 4, 2007 63


FFLLOOWW--TTHHRROOUUGGHH EEXXPPEERRIIMMEENNTTSS OOFF OORRGGAANNIICC CCOOMMPPOOUUNNDDSS IINN CCLLAASSTTIICC RREESSEERRVVOOIIRR RROOCCKKSS

Angela Meier1, Reinhard Gaupp1, Bernhard M. Krooss2, and Ralf Littke2

1 Friedrich-Schiller-University Jena, Burgweg 11, D-07749 Jena, Germany; [email protected] RWTH Aachen University, Lochnerstr. 4-20, D-52056 Aachen, Germany

Within the scope of the DFG-financed project (SPP1135) we investigate the interaction of petroleum com-pounds with hematite coatings on mineral surfaces inreservoir rocks and their effects on porosity and perme-ability. We want to evaluate the hypothesis that liquid hydrocarbons in hematitic reservoirs can generate reac-tive organic acids and/or carbon dioxide during post-emplacement thermal evolution. The expected outcomecould allow a better understanding of mechanisms of re-ductive bleaching in red sandstones by the presence ofliquid hydrocarbons and late stage (syn- and post-oil-charge) porosity enhancement in deep basinal settingswith methane source/reservoir potential (tight gasplays).

Flow-through experiments were carried out with redbed sandstones from the Upper Rotliegend and MiddleTriassic Bunter under elevated temperature (up to 200°C)and pressure (400 bar) conditions and different reactantfluids. The sandstone samples and the reactant fluids arecharacterised prior and after experiments. Preliminaryshort-term experiments started with acidic deionisedwater (ph 5.7). Mineral reactions are monitored by analy-

sis of the ionic species in the post experimental fluids byInductively Coupled Plasma-Mass Spectrometry/-OpticalEmission Spectrometry (ICP-MS/-OES) and titrationmethods. They showed a significant concentration of Silica, Calcium, Potassium, Aluminium, and carbonatespecies. Comparative petrographic-mineralogic investi-gations of the Rotliegend sandstone samples indicateleaching of carbonate cements and detrial feldspar grains.Pre- and post-experimental permeability measurementsshowed enhanced permeabilities after the leaching ex-periment. Further short-term and long-term (10 days) ex-periments were carried out with organic fluids consistingof a mixture of four n-alkanes (n-Hexane, n-Octane, iso-Octane and n-Decane) in equal volumes. Long-term ex-periments are planned with carbon dioxide, complex or-ganic fluids or petroleum in interaction with the inorganicframework of water saturated sandstone samples. In theadvanced stage of the investigations we will focus on thechange of the mineral surfaces caused by reactions withreactants in different scales by Scanning Electron Microscopy (SEM), Vertical Scanning Interferometry (VSI),Atomic Force Microscopy (AFM), and Transmission Elec-tron Microscopy (TEM).

Geo.Alp, Vol. 4, 200764


GGEEOOCCHHEEMMIISSTTRRYY OOFF DDEETTRRIITTAALL RRUUTTIILLEE IINN LLAATTEE PPAALLAAEEOOZZOOIICC SSEEDDIIMMEENNTTSS FFRROOMM CCHHIIOOSS,, GGRREEEECCEE

Guido Meinhold1, Birte Anders1, Dimitrios Kostopoulos2, and Thomas Reischmann3

1 Johannes Gutenberg-Universität, Institut für Geowissenschaften, Mainz, Germany ([email protected])2 National and Kapodistrian University of Athens, Department of Mineralogy and Petrology, Greece3 Max-Planck-Institut für Chemie, Abt. Geochemie, Mainz, Germany

Knowledge of the provenance of ancient clastic sedi-mentary rocks is important for exploration of mineral re-sources, for basin analysis as well as for palaeo-tectonicreconstructions. In addition to whole-rock petrography,geochemistry and heavy-mineral analysis, geochemicaldiscrimination studies of specific detrital minerals are apowerful tool in provenance characterisation. This studyfocuses on rutile that is one of the most stable heavy minerals during the sedimentation cycle and commonlypresent as an accessory phase in clastic sedimentary rocks.The Cr and Nb contents of rutile provide informationabout source rock lithology while its Zr content gives cluesabout its temperature of formation (Zack et al., 2004a, b;Watson et al., 2006), i.e. magmatic or metamorphic. In acase study, detrital rutile was separated from psammiticsamples belonging to three different sedimentary succes-sions (Carboniferous, Permo-Carboniferous, Permo-Trias-sic) that occur on Chios Island, Greece. The Ti, Cr, Al, Fe, Nb,Zr, Si, and V contents of the rutiles were obtained by elec-tron-microprobe analyses to retrace their provenance.

The Cr and Nb values of the analysed rutile grains showa wide range and indicate that this mineral in the Car-boniferous succession is mainly derived from metamaficrocks, whereas in the Permo-Carboniferous and Permo-Triassic successions from a metapelitic source. The calcu-lated formation temperatures using the Zr-in-rutile ther-mometer are 495–1000°C (according to Zack et al. 2004a)

or between 520–850°C (according to Watson et al. 2006)with more rutile of higher formation temperature occur-ring in the Permo-Carboniferous and Permo-Triassic suc-cessions. This feature together with the rutile chemistryindicate a change in source rock lithology through time,which could either reflect an increasing depth of erosionof an exhumed ‘Variscan’ nappe pile of heterogeneouscomposition in the hinterland or a change in the style ofaccretion and erosion of different terranes at the south-ern margin of Laurussia during the subduction of a branchof the Palaeotethys Ocean in the Late Palaeozoic. In general, this study underscores the importance of rutilechemistry and thermometry in quantitative single-miner-al provenance analysis and in chemostratigraphic analysisof clastic sedimentary rocks.

Watson, E.B., Wark, D.A. & Thomas, J.B. (2006): Crystal-lization thermometers for zircon and rutile. – Contrib.Mineral. Petrol., vol. 151: 413–433.

Zack, T., Moraes, R. & Kronz, A. (2004a): Temperature de-pendence of Zr in rutile: empirical calibration of a rutile thermometer. – Contrib. Mineral. Petrol., vol.148: 471–488.

Zack, T., von Eynatten, H. & Kronz, A. (2004b): Rutile ge-ochemistry and its potential use in quantitative pro-venance studies. – Sediment. Geol., vol. 171: 37–58.

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MMIICCRROOPPAALLAAEEOONNTTOOLLOOGGIICCAALL EEVVIIDDEENNCCEE OOFF SSAALLIINNIITTYY VVAARRIIAATTIIOONNSSIINN TTHHEE LLOOWWEERR TTRRIIAASSSSIICC ((GGRRIIEESSBBAACCHHIIAANN)) OOFF TTHHEE DDOOLLOOMMIITTEESS

Wolfgang Mette

Institut für Geologie und Paläontologie, Universität Innsbruck, Innrain 52, 6020 Innsbruck; [email protected]

The depositional environment of the Werfen Forma-tion has traditionally been interpreted as a protectedshallow marine bay. This assumption was based on palaeo-geographical reconstructions, as well as sedimentologicaland palaeontological criteria, particularly on the fact thatammonoids and stenohaline benthic organisms are veryrare and do not occur in pre-Spathian strata. The absenceof open marine Tethyan faunal elements is most probablydue to physical migration barriers and frequent environ-mental perturbations such as oxygen deficiency andsalinity fluctuations. The occurrence of oxygen deficiencyin the lower Werfen Formation (Mazzin Member) has beendeduced from trace fossil patterns, abundant occurrenceof pyrite and gammy ray spectrometry (Wignall & Twitch-ett 1996). Reduced salinity in the Griesbachian was de-duced from the composition of benthic fossil associations,particularly the occurrence of monotypic shelly macro-faunas (Lingula, Unionites) in the Mazzin Member.

Micopalaeontological analysis of the Mazzin Memberyielded different ostracod assemblages which stronglysuggest salinity variations. A marine euryhaline ostra-code fauna occurs 3 m above the Tesero Oolite in the Seissection. It consists of large and robust Paraparchitaceawithout spines representing 90% of the total ostracodfauna. These types of Paraparchitacea were oftenrecorded from various late Palaeozoic littoral environ-ments and are supposed to withstand strong salinitychanges (e.g. Bless 1983, Crasquin- Soleau et al. 2005,Tibert & Scott 1999). Due to strong diagenetic carapacealteration and deformation the determination of generaand species is difficult. A preliminary taxonomical analy-sis suggests, however, that the Paraparchitacea are rep-resented by at least 15 probably endemic species. Themarine euryhaline character of this microfauna is addi-tionally supported by the absence of ostracod taxawhich are usually abundant in late Palaeozoic-earlyMesozoic normal marine shelf environments (e.g.

Bairdia cea, Healdiacea). Com pletely different ostracodassemblages were recorded at 5 m and 6 m above theTesero Oolite. These assemblages show a higher ecologi-cal diversity, although they are strongly dominated bytwo species of Cavellina and Sargentina. The occurrenceof Judahella and Neoulrichia pulchra Kozur indicates anormal marine shallow subtidal milieu.

The present data show that ostracods are importantpalaeoenvironmental indicators in the Werfen Formationparticularly with respect to palaeosalinity. The record ofsalinity fluctuations within the Werfen Formation showsthat the faunal recovery pattern in the Lower Triassic ofthe Dolomites was not only controlled by changes ofpalaeo-oxygenation levels and is therefore not represen-tative for the global marine recovery pattern as suggestedby Twitchett (1999).

Bless, M.J.M., 1983: Late Devonian and Carboniferousostracode assemblages and their relationship to thedepositional environment. – Bulletin de la Sociétébelge de Géologie, 92 (1): 31.53.

Crasquin-Soleau, S., Vaslet, D. & Le Nindre, Y., 2005:Ostracodes as markers of the Permian/Triassic Bound-ary in the Khuff Formation of Saudi Arabia. – Palae-ontology, 48 (4): 853–868.

Tibert, N.E. & Scott, D.B. 1999: Ostracodes and aggluti-nated Foraminifera as indicators of paleoenviron-mental change in an Early Carboniferous BrackishBay, Atlantic Canada. – Palaios 14: 246–260.

Twitchett, R.J. 1999: Palaeoenvironments and faunal re-covery after the end-Permian mass extinction. – Pa-laeogeography, Palaeoclimatology, Palaeoecology154: 27–37.

Wignall, P.B. & Twitchett, R.J., 1996: Oceanic anoxia andthe end-Permian mass extinction. – Science 272:1155–1158.

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AA CCAASSEE SSTTUUDDYY OOFF AA PPOOLLYYPPHHAASSEE MMEEGGAA--IIMMBBRRIICCAATTEE ZZOONNEE::TTHHEE EEAASSTTEERRNN PPEERRIIAADDRRIIAATTIICC LLIINNEEAAMMEENNTT IINN TTHHEE KKAARRAAVVAANNKK MMOOUUNNTTAAIINNSS ((AAUUSSTTRRIIAA))

Sigrid Missoni and Hans-Jürgen Gawlick

University of Leoben, Department for Applied Geosciences and Geophysics, Peter-Tunner-Str. 5, A-8700 Leoben

According to the geological maps of the Austrian Geo-logical Survey the east-west trending Periadriatic Linea-ment (PL) separate the Eastern Alps (Northern KaravankMountains) and the Southern Alps (Southern KaravankMountains) in the study area. Former structural investiga-tions showed a laterally far less continuance due to strongsegmentation along high-angle faults of limited displace-ment, numerous of them displacing the lineament also. Thegeological structures of the Karavanks south of Maria Elendare dominated by E-W- to SE-NW-striking high-anglefaults, separating from each other in so far 24 imbricates,crosscuted by faults striking in NW-SE direction. They are ofvariable size, stratigraphic range, facies, palaeogeographicorigin and diagenetic/thermal overprint, which are testedby biostratigraphy, microfacies analysis and measurementsof the Conodont Colour Alteration Index (CAI). These indi-vidual segments, which derived from different palaeogeo-graphic positions of Triassic-Europe by far tectonic trans-portation of crustal fragments, can be clearly distinguish by1) stratigraphic range, facies and palaeogeographic origin,2) diagenetic/thermal overprint, and 3) a specific structuralinventory, which do not strike in the neighbouring seg-ments. These particular sets of structures restricted to indi-vidual tectonic entities were created before the amalgama-tion, and are thus transported structures. Paleozoic andMesozoic slices are mixed. However, there are successionswith affinities to most Triassic(-Jurassic) facies zones of theNorthern Calcareous Alps (NCA), the Southern Alps, and the“Slovenian-Bosnian Trough”. All these stratigraphic andstructural features indicate that enormous amounts of hor-izontal movements must exist between at least some ofthese tectonic slices. For example, small-scale segments ofPaleozoic sediments, which are located a) west ofMt. Kapellenberg, or b) west of Mt. Großer Muschenig oreast of Mt. Kleiner Muschenig, are marked by a complexityin both sedimentary successions and transported tectonicprocesses, bordered by a complex interplay of boundaryconditions. Beside the metamorphic (CAI ~6.0), hemipelag-ic Devonian limestones of segment I, comprise segment VIITrogkofel limestones with Permian shallow water organ-isms in partly crinoidal-rich grainstone-oncoids. Anothergeological complex segment with transported tectonics,located between the Maria-Elend Sattel to the Mt. Kahlko-

gel is characterized by ?Carnian strongly recrystallizeddolomites, overlain by a discontinuity of grey turbiditic tobioturbatic Sevatian radiolarian-rich wackestones and greyRhaetian to Jurassic argillo-calcareous turbiditic radiolari-an-rich wackestones. In these turbiditic, radiolarian-richwackestones the occurrence of Jurassic radiolarians is re-ported for the first time in this area. These mostly poor pre-served radiolarians indicate a Callovian age. Another inter-esting fact is the diagenetic/metamorphic overprint of dif-ferent segments in this area. To the north and northeastLate Carnian reef-near sediments reach CAI 5.5 to 6.0, cor-responding to low grade metamorphism. In addition to thestratigraphical and facies constraints also the CAI dataprove the mega-imbricate shear zone of the study area.These high values of CAI 5.5 to 6.0 are comparable with thefaciesequivalent thermally overprinted rocks of the Ultra-tirolic unit of the NCA or some individual slide blocks in theHallstatt Mélange. The thermal overprint of different tec-tonic slices in this region is therefore transported. Sum-marising the main structural events of the Karavank Moun-tains south of Maria Elend, the amalgamation of these im-bricates occurred during a long history of deformation in avariety of geodynamic frameworks, significantly changingin place and time. Despite some knowledge about generaltrends in deformation within the study area, e. g. the factthat the amalgamation of imbricates progressed fromsouth to north and the imbricate zone is often displaced byapproximately NE-SW-striking and even younger NW-SE-oriented high-angle faults of limited displacement. Theyoungest movements are comparable with the lateral tec-tonic extrusion. This is also kinematically in good correla-tion with data obtained from outcrops in Slovenia. Duringthe Oligocene extensive magmatism (Periadriatic tonalites)occurred, followed by dextral strike slip movements andmajor rotations. Lateral motions since the Turonian formeda mega-imbricate zone between the Dinarides and theEastern Alps contemporaneous with the movement of theDrau Range and the Transdanubian Range towards the east,to their present position.

With financial support of the FFG-Project 810082/9814in cooperation with the STW Klagenfurt AG - GeschäftsfeldWasser.

Geo.Alp, Vol. 4, 2007 67


MMAASSSS--FFLLOOWW DDEEPPOOSSIITTSS IINN TTHHEE LLAATTEE TTRRIIAASSSSIICC SSEEDDIIMMEENNTTAARRYY SSEEQQUUEENNCCEEOOFF TTHHEE SSLLOOVVEENNIIAANN TTRROOUUGGHH ((SSOOUUTTHH KKAARRAAVVAANNKK MMOOUUNNTTAAIINNSS,, AAUUSSTTRRIIAA))

Sigrid Missoni1, Hans-Jürgen Gawlick1, Paulian Dumitrica2, Leopold Krystyn3, and Richard Lein4

1 University of Leoben, Department for Applied Geosciences and Geophysics: Prospection and Applied Sedimentology,Peter-Tunner-Str. 5, A-8700 Leoben, Austria

2 Dennigkofenweg 33, CH-3073 Guemligen, Switzerland3 University of Vienna, Deparment of Palaeontolgy4 University of Vienna, Center for Earth Sciences, Althanstr. 14, A-1090 Vienna, Austria

The South Karavank Mountains of Austria show acomplex geological structure of large-scale mega- imbricate zones to the south of, and parallel to the east-ern Periadriatic Lineament. These zones display a suite ofindividual stratigraphic successions of partly differentpalaeogeographic origin and can be distinguished instratigraphic range, facies as well as in late dia -genetic/thermal history. Our study area is located be-tween the Maria-Elend Sattel to the east and the Rosen-bach Alm to the west where two laterally differing sequences are developed: the eastern sequence, locatedbetween the Maria-Elend Sattel to the Kahlkogel peak ischaracterized by ?Carnian recrystallized dolomites, directly and discontinuously overlain by grey bioturbaticUpper Norian radiolarian-rich wackestones and greyRhaetian bioturbated limy wackestones followed byJurassic argillo-calcareous mudstones. The western sequence, located in the area of the Bärengraben to theRosenbach Alm, is composed of Carnian recrystallizeddolomites, followed by ~200 meter thick grey Early toMiddle Norian cherty dolomites (= Baca dolomite in theSlovenian Trough), and is overlain by grey thin beddedlimestones of late Middle to Late Norian age with in-terbedded mass-flow deposits in the upper part (Krystynet al., 1994, Lein et al., 1995). From the two departingsuccessions we assume a primary basin inclination towards the Bärengraben sequence which received froma higher located part components and breccias now miss-ing in the Lower to Middle Norian Maria Elend sequence.The resedimented breccia components are dated by conodonts and radiolarians. The occurrence of Late Trias-sic radiolarians from the polymict Late Triassic mass-flowdeposits of the Bärengraben is reported for the first timein the Karavank Mountains. The mostly poor preserved,pyritized radiolarians again indicate an early to lateNorian age. Interestingly, almost all breccia componentsare limy and not dolomitic, as one would expect from thereworked sedimentary unit (= Baca Dolomite). One may

thus assume that the breccia components might haveeventually derived from a palaeogeographically differentsource area no longer exposed in the study area.

The predominantly matrix-supported clast layers areinterpreted as debris-flow deposits triggered by local(?)iterative tectonic pulses rather than by sea-level changesbecause of the several million years (Middle to early UpperNorian) lasting breccia formation. In the late Alaunian toearly Sevatian the northwestern Neotethys shelf was affected by transtensional tectonic events forming asym-metric basins in the Hauptdolomite/Dachstein carbonateplatforms of the Northern (Seefeld formation, Aflenzbasin, Pedata basin – e.g., Gawlick 1998) and SouthernAlps. Coeval events have probably similarly affected theSouthern Karavanks and may be more widespread devel-oped in the Alpine-Mediterranean domain than previous-ly known.

With financial support of the FFG-Project810082/9814 in cooperation with the STW Klagenfurt AG- Geschäftsfeld Wasser.

Gawlick H.-J. (1998): Obertriassische Brekzienbildungund Schollengleitung im Zlambachfaziesraum (Pöt-schenschichten) - Stratigraphie, Paläogeographie unddiagenetische Überprägung des Lammeregg-Schol-lenkomplexes (Nördliche Kalkalpen, Salzburg). – Jb.Geol. B.-A. 114411 (2): 147–165, Wien.

Krystyn, L., Lein, R., Schlaf, J. & Bauer, F. (1994): Über einneues obertriadisch-Jurassisches Intraplattform-becken in den Südkarawanken. – Jubiläumsschrift 20Jahre geologische Zusammenarbeit Österreich- Ungarn, Tl. 2, 409-416, 4 Abb., Wien.

Lein, R., Schlaf, J., Müller, P.J., Krystyn, L. & Jesinger, D.(1995) : Neue Daten zur Geologie des Karawanken-Strassentunnels. – Geol. Paläont. Mitt. Innsbruck, 2200,371–387, 6 Abb., 1 Taf., Innsbruck.

Geo.Alp, Vol. 4, 200768


PPEETTRROOGGRRAAPPHHIICC EEVVIIDDEENNCCEE OOFF DDRRAAIINNAAGGEE BBAASSIINN CCHHAANNGGEESS IINN TTHHEESSEE AALLPPSS FFRROOMM TTHHEE MMEESSSSIINNIIAANN TTOO PPLLEEIISSTTOOCCEENNEE:: TTHHEE TTAAGGLLIIAAMMEENNTTOO PPAALLAAEEOOVVAALLLLEEYY ((NNEE IITTAALLYY))

Giovanni Monegato1 and Cristina Stefani2

1 Georisorse e Territorio Dept., Udine University, Via Cotonificio 114, 33100 Udine (Italy)2 Geoscience Dept., Padova University, Via Giotto 1, 35122 Padova (Italy)

As most valleys in the Southern Alps, the Tagliamentovalley was deeply entrenched as a result of Late Messin-ian sea level drop.

In the valley-filling deposits six different unconfor-mity-bounded Stratigraphic Units have been distin-guished, which can be traced along the valley for severalkilometres and allow reconstruction of the palaeo -drainage during the considered time span. The sedimen-tary bodies have been classified as intra-valley coarse-grained fluvial and piedmont alluvial fan related tobraided fluvial systems, and Gilbert-type delta conglom-erates and sandstones.

Sandstone and pebble petrography supported thestratigraphic subdivision evidencing the evolution of thecatchment with time. The older units are characterisedby a high carbonate fraction, mostly dolostone andlimestone rock fragments, suggesting a drainage basinconfined in the Prealps sector where these types of rockslargely crop out. A sharp change in composition occurs

between the second and the third unit (Messinian-Pliocene boundary), when the river deposits becamemore polymict and richer in non carbonate rock frag-ments, indicating an extension of the catchment towards north, in the Carnian Alps. The fourth unit ischaracterised by an increase in carbonate elements; thiscould suggest a new extension of the drainage basin inthe Prealps and a likely enhance of sediment supply sup-ported by the Pliocene tectonic activity in the prealpinearea. In the younger units of middle Pleistocene age aspread of non-carbonate rock fragments is visible.

To sum up, the trends of the main rock fragmentclasses show an increase of the limestone fragment ratioand a similar growth of the siliciclastic elements towardsthe younger units. These types of rock fragments wereeroded from the Palaeozoic successions, cropping out inthe Carnian Alps, from the early Pliocene and it wasprobably intensified by the spread of the glaciers frommiddle Pleistocene onwards.

Geo.Alp, Vol. 4, 2007 69


SSIILLIICCIICCLLAASSTTIICC SSTTRRAATTIIGGRRAAPPHHYY IINN AANN EEXXPPEERRIIMMEENNTTAALL TTAANNKK

Martin Nagel, Christoph Heubeck, and Dorothee Mertmann

Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstr. 74- 100, 12249 Berlin; [email protected]

The correct deciphering of (continuous) time in a (dis-continuous) stratigraphic reocrd has been one of the fun-damental issues of stratigraphy. It is exemplified by theaccommodation space equation T + E = S + W, where T isthe rate of tectonic subsidence, E is the rate of eustaticsea-level rise, S is the rate of sedimentation, and W is therate of water depth increase (or deepening). Conveyingthe complex interplay of these factors as theory to stu-dents in the classroom, in particular when loaded with theterminology of sequence-stratigraphic concepts, has tra-ditionally been problematic. The design of appropriate ex-ercises, usually practising the proper reconstruction ofpast events from industry 2-D seismic reflection lines, hasalso been challenging.

We constructed a simple portable experimental tank tobetter communicate concepts and common geometries oflithostratigraphic units at passive continental margins toundergraduate geology students. This tank allows to varyeustatic sea level, sediment supply and tectonic subsi-dence through base level change in two dimensions. Thetank measures 1m (width) x 0,50 m (height) x 0,02 m(thickness) and uses a transparent plexiglas frontboard,adjustable water inflow and outflow taps, a gravity-fedadjustable sediment supply of fine-grained sand, and anumber of freely moveable magnets supporting a flexible

rubber strip. The latter make adjustments to basementgeometry during the experiments possible. Colouredsands, injected at the right time, accentuate the geometryof individual key units (such as incised valley fills, low-stand deltas, lowstand basin floor fans, highstand deep-water condensed sections) and key horizons (such as se-quence boundaries, maximum flooding surfaces, andshelf-slope seals).

This experimental setup enables the modelling of theprincipal stacking pattern geometries along passive mar-gins, consisting of several generations of successive High-stand (HST) and Lowstand System Tracts (LST) while plain-ly illustrating the dependency of the generated prograda-tional or regressive geometries on the interplay of theabove-mentioned variables. As a consequence, studentsare more likely to recognize unconformities and missinggeologic time in seismic sections and correlate correctlythe equivalent sedimentary bodies along sequence-strati-graphic surfaces when later exposed to large-scale seismicsections. Digital movies in lecture classes and student-di-rected experiments in exercise sections using this tank willfacilitate the communication of concepts requiring advanced stratigraphic understanding, such as regionalstratigraphic syntheses, seismic interpretation, and petro-leum geology.

Geo.Alp, Vol. 4, 200770


PPLLEEIISSTTOOCCEENNEE FFLLUUVVIIAALL TTEERRRRAACCEESS OOFF TTHHEE SSVVRRAATTKKAA RRIIVVEERR –– FFAACCIIEESS AANNDD PPRROOVVEENNAANNCCEE SSTTUUDDYY

Slavomír Nehyba1 and David Buriánek2

1 Department of Geological Sciences, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic;[email protected]

2 Czech Geological Survey, Leitnerova 22, 658 69 Brno, Czech Republic; [email protected]

The middle course of the Svratka river flows throughthe geologically and geomorphologically complex areaaround the city of Brno. This area underwent a dynamicdevelopment during the Quaternary. Terrace system alongthe river course developed, witnessing the alternating in-cision and deposition phases during the last 1 Ma. TheQuaternary uplift of the area can be deduced from the in-cision record of the river system. Sea level changes are as-sumed to have played negligible role (distance to thecoastline, low river gradient).

Three successive river terraces (Pleistocene) were stud-ied within the terrace staircase, the highest of which isabout 60 m and the lowest about 15 m above the presentriver. Preservation of the river deposits is mostly fragmen-tary. The middle terrace (ca. 40 m above the present river) isthe best preserved one (with largest lateral extent andthickness). The terrace sediments are composed of fluvialgravels and sands. Architectural components within the

outcrops were defined and include: 1) basal, thalweg-filldeposits, 2) crudely stratified gravely barform deposits,and 3) inclined gravely and sandy barform deposits. Resultsof facies study reveal deposition in high-energy rivers.

Preserved fluvial deposits provide important sedimen-tary archive witnessing the condition within both prove-nance and depositional area during the Pleistocene.Provenance studies are based on the petrography of thepebbles and cobbles, heavy mineral assemblages and re-sults of microprobe analyses of selected minerals (garnet,tourmaline, rutile, spinel). Varying role of distant (crys-talline rocks of Moravicum, Svratka and Poli#ka Crys-talline Units) and local (Neogene deposits of the Carpathi-an Foredeep, Permian deposits of the Boskovice Furrow,Devonian conglomerates/”Old Red facies” and magmaticrocks of the Brno Massif) sources can be followed withinthe terrace system and the possible evolution of thesource area interpreted.

Geo.Alp, Vol. 4, 2007 71


CCAAVVEE EEXXCCEENNTTRRIIQQUUEESS FFRROOMM BBRREEIITTSSCCHHEEIIDD ((NNWW HHEESSSSEE,, GGEERRMMAANNYY))::UUNNUUSSUUAALL SSPPEELLEEOOTTHHEEMMSS WWIITTHH UUNNUUSSUUAALL CCAALLCCIITTEE SSTTRRUUCCTTUURREE AASS PPRROOVVEEDD BBYY EELLEECCTTRROONN

BBAACCKKSSCCAATTTTEERR DDIIFFFFRRAACCTTIIOONN ((EEBBSSDD))

Rolf D. Neuser and Detlev K. Richter

Institut für Geologie, Mineralogie u. Geophysik, Ruhr-Universität-Bochum

Excentriques (= helectites) are elongated to vermicu-lar, mostly cm-sized speleothems with a small (� < 0.5mm) central canal growing indepentently from gravity.Their exact genetical conditions are still mostly not un-derstood (Hill & Forti 1997). In most cases calcite excen-triques are composed of single crystals (1) (Kempe &Spaeth 1977) or wedge-shaped crystals (2) (Moore 1954).

Our special interest was focused on the polycrystallinestructure of the calcites forming the vermicular excen-triques from a tributary branch of the Breitscheid- Erdbach cave system which unfortunately is destroyed bynow. In thin sections under crossed polarizers the diver-gent fibrous structure of these speleothems proves to bequite complex. The modern Electron BackScatter Diffrac-tion (EBSD) method reveals the following structure:

Starting from the central part with the canal where thec-axes of the calcite fibres are oriented parallel to theelongation of the excentrique, the cross section revealsthree similar sectors with increasing inclination of the c-axes towards the outer rim. This divergence has a maxi-mum in the central outer part of the sectors and decreasesto their lateral sides where the orientation is parallel tothe elongation of the excentrique again just like in thecentral part of the section.

This pattern was observed in the thicker adult portionsof the samples. As the terminations of the excentriquesare shaped nearly pointed most of the calcitic precipita-

tions must have taken place externally. Calcite formationfrom biofilms seems to be most probable for the excen-triques. Here, microbes could profit from the supply withnutrient through the central canal and additionally con-tribute to calcite precipitation. These considerations maybe a potential field of microbiological investigationswhich repeatedly arose from genetical interpretations ofspeleothems (Northup et al. 1997). Besides a possible bio-genic influence on the formation of excentriques thethree sectors seen in the cross section may reflect the trig-onality of calcite. But in respect of an exact understand-ing of the excentriques more investigations are necessary.

Hill, C. & Forti, P. (1997): Cave minerals of the world. – Second edition, National Speleological Society, 463 p.

Kempe, S. & Spaeth, C. (1977): Eccentrics: Their capilla-ries and growth rates. – Proceedings of the 7th Inter-national Speleological Congress Sheffield 1977,259–262.

Northup, D., Reysenbach, A. & Pace, N. (1997): Microor-ganisms and speleothems. – In: Hill, C., Forti, P.(1997): Cave minerals of the world. Second edition,National Speleological Society, 261–266.

Moore, G.W. (1954): The Origin of Helectites.- OccasionalPaper No1, National Speleological Society, Hunts -ville/Alabama.

Geo.Alp, Vol. 4, 200772


PPLLIIEENNSSBBAACCHHIIAANN RRAADDIIOOLLAARRIIAANNSS IINN TTEELLTTSSCCHHEENNGGRRAABBEENN ((NNOORRTTHHEERRNN CCAALLCCAARREEOOUUSS AALLPPSS,,SSAALLZZKKAAMMMMEERRGGUUTT AARREEAA,, AAUUSSTTRRIIAA)):: AA KKEEYYSSTTOONNEE IINN RREECCOONNSSTTRRUUCCTTIINNGG TTHHEE EEAARRLLYY JJUURRAASSSSIICC

EEVVOOLLUUTTIIOONN OOFF TTHHEE NNEEOOTTEETTHHYYSS

Luis O´Dogherty1 and Hans-Jürgen Gawlick2

1 Universidad de Cádiz, Facultad de Ciencias del Mar y Ambientales: Ciencias de la Tierra, Campus del Río San Pedro s/n,ES-11510 Puerto Real

2 University of Leoben, Department for Applied Geosciences and Geophysics: Chair of Prospection and Applied Sedimentology,Peter-Tunner-Str. 5, A-8700 Leoben; [email protected]

In the „Hallstatt Mélange“ located in the northwest ofBad Mitterndorf, a slide of Pliensbachian marly radiolaritesoccurs in an upper-Middle to lower-Upper Jurassic succes-sion. The matrix consists of radiolarites, cherty limestonesand marls, dated by radiolarians as upper-Middle Jurassic(Callovian). The microfacies and lithology (mainly chertysediments) of the Pliensbachian slide are nearly identical tothose of the matrix, but it belongs to the Lower Jurassic Dür-rnberg Formation of the outer-shelf area of the NorthernCalcareous Alps (Hallstatt Zone), which was paleogeograph-ically situated in the north-western rim of the NeotethysOcean. The radiolarian fauna has low diversity but its goodpreservation allows an accurate age determination. The dat-ing of that cherty slide as Pliensbachian is of high impor-tance because: 1) it notices the first finding of sedimentsyounger than Sinemurian in the Hallstatt Zone of the North-ern Calcareous Alps; 2) it represents the first record of Pliens-bachian radiolarians in the European Alpine area; 3) it con-firms that the north-western passive margin of theNeotethys Ocean persisted in the Alps at least until thePliensbachian. Our paleontological and stratigraphic dataprove that the closure of the Neotethys Ocean in this regionis younger than Pliensbachian, but older than Callovian.

We determine following radiolarians: Foremania sandi-landsensis WHALEN and CARTER, Canoptum dixoni PES-SAGNO and WHALEN, Parahsuum longiconicum SASHIDA,Laxtorum sp., Laxtorum sp., Parahsuum mostleri (YEH), Prae-caneta ? sp., Parahsuum edenshawi (CARTER), Parahsuumsimplum YAO, Katroma megasphaera YEH and CHENG, Ka-troma cf. bicornus DE WEVER, Katroma angusta YEH, Bago-tum cf. modestum PESSAGNO and WHALEN, Lantus obesus(YEH), Lantus sp. A, Gorgansium sp. 1, Lantus sp. A, Nassellar-ia NA2 sensu YAO, Orbiculiformella callosa (YEH), Spon-gotropus sp., Praeconocaryomma sp. 2 sensu CARTER inprogress, Spongotripus sp. B sensu YAO, Paronaella sp. 1,Pantanellium inornatum PESSAGNO and POISSON, Paron-aella bona (YEH), Paronaella tripla DE WEVER, Paronaellabona (YEH), Homoeparonaella lowryensis WHALEN andCARTER, Hagiastrum sp. 1, Hagiastrid g. et sp. indet G sensuYAO (new species) WHALEN and CARTER, Cyclastrum sp. A

(new species), Crucella spongase DE WEVER, Archaeohagias-trum longipes BAUMGARTNER.

Middle and Late Jurassic as well as Early Jurassic radiolar-ian faunas from cherty sediments have been studied in theNorthern Calcareous Alps in recent times. The Middle to LateJurassic radiolarian faunas are well known from a taxonomicand biochronological point of view, whereas some problemsremain. By this, in the Northern Calcareous Alps these radio-larian faunas are used for the reconstruction of the basin dy-namics and the reconstruction of the destruction of the dis-tal European continental margin in late Middle to LateJurassic due to the closure of the Tethys Ocean.

Early Jurassic radiolarian assemblages in the NorthernCalcareous Alps as well as in the Tethyan realm are rare (Gor-ican et al. 2003). Hettangian to Sinemurian radiolarian as-semblages in the Northern Calcareous Alps are described byKozur & Mostler (1990) for the continent near part (lowernappe system) of the Northern Calcareous Alps and fromGawlick et al. (2001) for the continent far part (HallstattMélange). The discovery of a wellpreserved and diverse ra-diolarian fauna in Teltschengraben northwest of Bad Mit-terndorf represents the first record of Pliensbachian radio-larians in the northwestern Tethys.

Gawlick, H.-J., Suzuki, H. & Missoni, S. (2001): Nachweis vonunterliassischen Beckensedimenten in Hallstätter Fazies(Dürrnberg-Formation) im Bereich der Hallein - Bercht-esgadener Hallstätter Zone und des Lammer Beckens(Hettangium – Sinemurium). – Mitt. Ges. Geol. Bergbaus-tud. Österrr. 4455: 39–55, Wien.

Gorican, S., Smuc, A. & Baumgartner, P.O. (2003): ToarcianRadiolaria from Mt. Mangart (Slovenian-Italian border)and their paleoecological implications. – Marine Mi-cropaleontology 4499: 275–301, Amsterdam.

Kozur, H. & Mostler, H. (1990): Saturnaliacea Deflandre andsome other stratigraphically important radiolaria fromthe Hettangian of Lenggries/Isar (Bavaria, northern cal-careous Alps). – Geol. Paläont. Mitt. Innsbruck, 1177:179–248, Innsbruck.

Geo.Alp, Vol. 4, 2007 73


GGEEOOLLOOGGYY OOFF TTHHEE BBOOSSNNIIAANN FFLLYYSSCCHH ((SSAARRAAJJEEVVOO –– ZZEENNIICCAA AARREEAA,, BBOOSSNNIIAA AANNDD HHEERRZZEEGGOOVVIINNAA))PPAARRTT 22:: DDEEFFOORRMMAATTIIOONN AANNDD BBUURRIIAALL HHIISSTTOORRYY

Rüdiger Petri1, Dominik Christ1, Georg Grathoff1, István Dunkl1,*,Gerd Rantitsch2, Klaus Wemmer3, Tamás Mikes1, Hazim Hrvatovi$4, and Hilmar von Eynatten1

1 Department of Sedimentology and Environmental Geology, Geoscience Center Göttingen, Germany2 Mining University of Leoben, Department of Applied Geosciences and Geophysics3 Department of Isotope Geology, Geoscience Center Göttingen, Germany4 Geological Survey, Sarajevo, Bosnia and Herzegovina* Corresponding author: E-mail: [email protected]

The Bosnian Flysch is a Mesozoic tectonostratigraphicunit of the Dinarides stretching from the Southern Alps-Dinarides transition in the NW to the Skadar-Pe$ fault inthe SE. Structurally the Bosnian Flysch is underlain by theAdriatic-Dinaride carbonate platform nappes, the Una-Ku#i Nappe, and the Mid-Bosnian Schist Mountains. To theNE, it is bordered by the Pannonian-Golija-Macedoniannappe, the Dinaride Ophiolite Zone and the Durmitor-Gashi Nappe.

The Bosnian Flysch consists of two major units. Thelower unit (Vranduk Fm.) is composed mainly of Jurassic toLower Cretaceous micritic limestones, marls, shales andsiliciclastic-dominated sandstones. The upper unit (UgarFm.) comprises Upper Cretaceous thin-bedded marly tomicritic limestones and marls alternating with carbonategravity-flow deposits. This unit is characterized by highcarbonate content and synsedimentary deformationalfeatures (e.g. slumping).

The Vranduk Fm. commonly exhibits outcrop-to-map-scale tight folds (inclined and overturned) and thrustfaults. Joints perpendicular to bedding are frequent. TheUgar Fm. is dominated by open to tight folds. Fold ver-gence and top-to-SW tectonic transport indicators in bothunits are in agreement with the general Dinaridic strike.

Pelite samples for burial history analysis were taken-from the Vranduk Fm., the Ugar Fm. and the black shalematrix of the ophiolite mélange. From each sample, the <2µm and <0.2 µm grain-size fractions were used to deter-mine K/Ar age, Kübler-Indices (KI), proportions of the illitepolytypes, and percent illite in illite/smectite mixed layers.Quantitative clay mineralogy was determined in the <2 µmfraction.

The dominant phase is illite (54–86%) with up to 10%smectite. Chlorite with varying Fe contents amounts up to46%. Corrensite (<35%) and other chlorite/smectite mixedlayers were also found. Kaolinite occurs only in the UgarFm., whereas serpentine is restricted to the ophiolitemélange matrix. Corrensite and chlorite/smectite are ab-sent in the Bosna Valley samples. In the <2µm fraction theKI vary between 0.24-0.62°2$ in the Stavnja Valley andbetween 0.39-0.45°2$ in the Bosna Valley. The KI of the

<0.2 µm fraction are higher than those of the <2 µm frac-tions.

Illite polytype quantification of the <2 µm fraction in-dicates a dominance of 1Md (43–80%) of 2M1 (7-53%) il-lite. There is no regional trend in the illite polytype distrib-ution within the profiles. Illite proportions in illite/EG-smectite exceed 90% in both profiles.

K/Ar ages decrease southwards. Stavnja Valley <2 µmsamples range in age, from north to south, from 168.4 +/-3.6 Ma in the ophiolite mélange through 132.6 +/-2.9 Main the Vranduk Fm. to 129.7 +/-2.9 Ma in the Ugar Fm. Agesmeasured on the <0.2 µm fraction range between 149 +/-3.4 Ma and 111.9 +/-2.5 Ma. Bosna Valley samples rangebetween 156.3 +/-3.4 Ma and 138.7 +/-3.3 Ma (<2 µm) aswell as 137.8 +/-3.0 Ma and 118.9 +/-2.6 Ma (<0.2 µm). Nocorrelation exists between K/Ar ages and the proportionsin 2M1 illite polytypes.

Vitrinite reflectance data from both flysch units andfrom the ophiolite mélange matrix indicate a maximumoverprint temperature of 100–200°C assuming an effec-tive heating time of 10 Ma. Along the Bosna Valley profile,Ro values vary systematically from 1.9% to 0.8% and indi-cate a southward decrease in thermal overprint. In theStavnja Valley profile the vitrinite reflectance varies from1.3 to 2%, with the highest values occurring below thetop-to-SW thrust sheets.

K/Ar ages display no correlation with results from theother thermal indicators (KI, Ro%, %I (I/S)) suggesting thatthe ages result from the coexistence of detrital illite withauthigenic illite in the sequence. Therefore, burial depthestimation by means of KI and percent illite in illite/EG-smectite alone is not a reliable tool in the investigated pro-files. However, maximum temperatures yielded by vitrinitereflectance measurements suggest a burial depth of 4 to 8km assuming 25 °C/km geothermal gradient. Due to thepresence of some detrital illite and the low thermal over-print, the K/Ar ages are probably slightly older than themain deformation event. Combined with our biostrati-graphic data (Christ et al., this volume), deformation of theVranduk Formation of the Bosnian Flysch took place mostlikely between 120 and 100 Ma.

Geo.Alp, Vol. 4, 200774


DDEERR TTSSCCHHIIRRGGAANNTT BBEERRGGSSTTUURRZZ ((NNÖÖRRDDLLIICCHHEE KKAALLKKAALLPPEENN,, TTIIRROOLL)):: PPRROOMMIINNEENNTTEESS FFAALLLLBBEEIISSPPIIEELLEEIINNEERR LLIITTHHOOLLOOGGIISSCCHH UUNNDD SSTTRRUUKKTTUURREELLLL PPRRÄÄDDIISSPPOONNIIEERRTTEENN FFEELLSSGGLLEEIITTUUNNGG

Christoph Prager1,2, Lucas Pagliarini3, and Rainer Brandner3

1 alpS Zentrum für Naturgefahren Management, Grabenweg 3, 6020 Innsbruck, Österreich2 ILF Beratende Ingenieure ZT GmbH, Feldkreuzstraße 3, 6063 Rum b. Innsbruck, Österreich3 Institut für Geologie und Paläontologie, Universität Innsbruck, Innrain 52, 6020 Innsbruck, Österreich

Mit einem Ablagerungsvolumen von über 200 Mill. m3

(Abele, 1974) zählt der Tschirgant Bergsturz (TBS) in den westli-chen Nördlichen Kalkalpen zu den größten Massenbewegun-gen im Alpenraum. Das weitflächig und tiefgründig auf-gelockerte Abbruchgebiet besteht aus mittel- bis obertriadi-schen Karbonatgesteinen der südlichen Inntal-Decke, die po-lyphas und heteroaxial gefaltet und zerschert wurden (Eisba-cher &Brandner, 1995). Südlich angrenzend folgt die NE-strei-chende Oberinntal-Störungszone, die aus der Tertiären, NW-gerichteten, durchreißenden Überschiebung des Ötztal-Grundgebirgskomplexes auf den Kalkalpensüdrand hervorge-gangen ist. NW-streichende dextrale Blattverschiebungendurchtrennen diese Überschiebungszone und den Deckensta-pel der Kalkalpen in der Liegendscholle. Die tief reichende Ka-taklase ermöglichte eine beträchtliche fluvio-glaziale Eintie-fung des Inntals zwischen den Nördlichen Kalkalpen und demÖtztal-Kristallin.

Das Abbruchsgebiet des TBS, die sog. Weißwand, bestehtvorwiegend aus grob gebankten Dolomiten der Wetterstein-Fm und aus engschichtigen Wechselfolgen von Tonschiefern,Dolomiten und Evaporiten (Rauh wacken) der Raibler Schich-ten. Diese kommen infolge der Deckenstapelung sowohl imLiegenden als auch im Hangenden der Wetterstein-Fm vor,an deren Basis zudem noch geringmächtige ReichenhallerSchichten (am Überschiebungskontakt) und gut geschichte-te Kalke und Dolomite der Gruppe des Alpinen Muschelkalkserhalten sind.

Strukturell ist hier ein bemerkenswerter, weil geometrischäußerst komplex deformierter Großfaltenbau mit z.T. starküberkippten Lagerungsverhältnissen erkennbar. Der Tschir-gant ist Teil des Südschenkels der Großstruktur der Tarrenz-Synklinale und wurde im Zuge der Überschiebung des Ötztal-Komplexes steil gestellt und überkippt. Die vorausgegange-ne, NW-gerichtete Deckenüberschiebung der Inntaldeckeäußert sich in der Stapelung mehrerer Teilschollen, wobei dieEvaporite der Reichenhaller Schichten und der RaiblerSchichten als Abscherungshorizonte dienten. Faziell gesehenerfolgte die Deckenstapelung im Bereich der Faziesverzah-nung zwischen der Karbonatplattform der Wetterstein-Fmund Beckensedimenten der Partnach-Fm. Entlang der NE-streichenden schräg sinistralen Tschirgant-Störung wurdeder Wetterstein-Riffkalk des Tschirgants nach Süden steil aufstratigraphisch jüngere Dolomite der lagunären Wetterstein-Fm rücküberschoben (Pagliarini, in Vorb.).

Aufgrund der lithofaziellen Ausbildung und komplexenSpröddeformation sind hier sowohl die Anlagen potentiel-ler Gleitflächen als auch die Blockgrößenverteilungen derSturzmassen deutlich strukturell vorgegeben. Wesentlichist v.a. die stufenweise Vernetzung von SE-fallenden, i.e.häufig überkippten, Schichtflächen und NE-streichendensinistralen Bruchzonen mit NW-streichenden dextralenStörungen und Klüften. Im Bereich Weißwand zeigen diekompetenten, tektonisch intensiv überprägten Dolomiteder Wetterstein-Fm markante Trennflächensysteme(Schicht- und Störungsflächen, Klüftung), die listrisch ausdem Hang streichen und als pultartige Gleitflächen fun-giert haben.

Zudem wurde das Versagen des TBS vermutlich durchKarststrukturen in der Wetterstein-Fm und durch das Auf-treten Zehner-Meter mächtiger Rauhwacken der RaiblerSchichten am Hangfußbereich gefördert. Mehrere signifi-kant mineralisierte Quellaustritte weisen auf Lösungspro-zesse von Evaporiten hin. Dadurch kann es zur Erhöhung derGesteinsporosität bzw. zu einer Mächtigkeitsreduktion derEvaporite gekommen sein, was ein gravitatives Nachsackender hangenden, spröden Dolomite hervorrufen würde. Die-ser Vorgang wird als langfristiger, prädisponierender Entfe-stigungsprozess angesehen. Dem entsprechend gibt es imAbbruchgebiet des TBS und den angrenzenden Gebietenzahlreiche Hinweise für ältere Sackungs- und Kippbewe-gungen („toppling“) mit Bildung steil stehender, spaltenför-miger Hohlräume die mit bereits verfestigten Breccien ver-füllt sind.

Abbruchgeometrien und Ablagerungsgefüge der Sturz-massen belegen, dass sich hier eine initiale Felsgleitung zueinem mobilen Sturzstrom entwickelte, der vor ca. 2900 14Cyrs das Inntal verschüttet hat und mindestens 6 km weit indas vordere Ötztal eindringen konnte (Prager et al., dieserBand).

Abele, G. (1974): Bergstürze in den Alpen. Ihre Verbrei-tung, Morphologie und Folgeerscheinungen. – Wiss.Alpenvereinshefte, 25: 1–230, München.

Eisbacher, G.H. & Brandner, R. (1995): Role of high-anglefaults during heteroaxial contraction, Inntal ThrustSheet, Northern Calcareous Alps, Western Austria. –Geol. Paläont. Mitt. Innsbruck, 20: 389–406.

Geo.Alp, Vol. 4, 2007 75


DDYYNNAAMMIICCSS OOFF AANN EEAARRLLYY MMIIOOCCEENNEE TTUURRRRIITTEELLLLIINNEE GGAASSTTRROOPPOODD MMAASSSS OOCCCCUURRRREENNCCEE((NNOORRTTHH AALLPPIINNEE FFOORREELLAANNDD BBAASSIINN))

Michael W. Rasser1 and James H. Nebelsick2

1 Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, D-70191 Stuttgart; [email protected] Institut für Geowissenschaften, Universität Tübingen, Sigwartstrasse 10, D-72076 Tübingen; [email protected]

The mass occurrence of gastropods is a frequently ob-served, though poorly understood sedimentological and(palaeo)biological phenomenon. One of the fairly well-known groups forming such low-diversity accumulatonsare turritelline gastropods, which can occur in high localdensities from the Cretaceous until today. Present-dayturritelline gastropods are well known and occur world-wide from the shallower to the deeper seas (c. 0-1500 mwater-depth, more typically 10-100 m). They are suspen-sion feeders living partly digged into the substrate, +/-parallel to the sea-floor surface. Mass occurrences usuallyoccur in shallow-subtidal, siliclastic environments rich innutrients due to upwelling

A spectacular example of a fossil turritelline mass oc-currence is the so-called ‘Erminger Turritellenplatte’ westof Ulm. This occurrence is part of the Early Miocene ‘UpperMarine Molasse’ unit (‘Obere Meeresmolasse’) in SW Ger-many, which represents a mainly siliciclastic marine stage

of the development of the Alpine Foreland Basin. The ‘Erminger Turritellenplatte’ was deposited relatively closeto the northern shoreline and is supposed to having devel-oped during the maximum flooding of the Molasse Sea.

The ‘Erminger Turritellenplatte’ is an erosional relic,forming an at least 3.5 m (probably up to 7 m) thick, well-cemented bed with a lateral extension of a few kilome-tres. The succession is dominated by sandy limestone,sandstone and sand with the gastropod Turritella turrisoccurring in rock-forming quantities, as well as clayeysediments that lack gastropods. Furthermore, the bivalvePitar helvetica as well as oysters and fragments of barnacles occur. Based on detailed sedimentological,palaeontological and taphonomical studies, this paperdiscusses the sedimentary and biological dynamics be-hind this unique mass occurrence, the interpretation ofwhich is highly biased by diagenetic and, probably, bio -stratinomic effects.

Geo.Alp, Vol. 4, 200776


PPRROOVVEENNAANNCCEE OOFF OORRDDOOVVIICCIIAANN AANNDD DDEEVVOONNIIAANN SSIILLIICCIICCLLAASSTTIICC SSAANNDDSSTTOONNEESSFFRROOMM SSOOUUTTHHEERRNN PPEERRUU AANNDD NNOORRTTHHEERRNN BBOOLLIIVVIIAA

Cornelia Reimann and Heinrich Bahlburg

Geologisch-Paläontologisches Institut und Museum, Westfälische Wilhelms- Universität Münster, Corrensstrasse 24,48149 Münster; [email protected]

We use provenance analysis as a tool for the paleogeo-graphic reconstruction of the Western Gondwana marginof southern Peru and northern Bolivia during Ordovicianand Devonian time. For the study of the siliciclastic sand-stones of southern Peru and northern Bolivia differentprovenance-indicative methods were applied (light miner-al, heavy mineral, whole-rock geochemical analysis andgeochemistry of tourmalines) in order to get a comprehen-sive dataset.

The Ordovician sandstones of the Sandia (southern Peru)and equivalent Amutara Formations (northern Bolivia)were deposited in the Peru-Bolivia Through in a back-arcposition. The Peru-Bolivia Trough had a NW-SE strike direc-tion and was limited by the Arequipa Massif to the south-west and the Brazilian shield to the northeast. The Ordovi-cian successions have a thickness of up to 7000 m and sedi-ment structures such as current ripples and crossbeddingimply a paleocurrent-direction towards the SW. The sand-stones of the Sandia and Amutara Formations are matureand relatively quartz-rich but they have a high matrix con-tent of usually well above 20%. To approach the originalcomposition of framework minerals the normative compo-sition was combined with the whole rock geochemistry ofthe sediments. After recalculation most of the sedimentsstill show a well-recycled nature but indicate a significantlarger content of labile components like feldspars and rockfragments. Some of the Sandia Formation sandstones resultin having a normative framework composition typical ofarc sediments. This arc signature is reinforced by consider-ing the provenance-indicative ratios of immobile incom-patible (e.g. La, Th) to compatible (e.g. Co, Sc, Ti) elements,gathered from whole-rock geochemical analysis. Approxi-mately half of the 26 samples from the Sandia and AmutaraFormations are felsic, with ratio values typical of sedimentsof a passive margin setting, whereas the other half is lessfelsic and preserve characteristics of an active continentalmargin source. The heavy-mineral spectrum in general andthe chemical composition of tourmalines in particular indi-cate significant reworking of the sediments before deposi-tion. The heavy mineral content is dominated by the stableminerals zircon, tourmaline and rutile (ZTR; mostly more

than 90%). Considering the indicative elements Al, Fe, Mgand Ca in the tourmaline chemistry, 85% of the tourmalinesfrom the Sandia and Amutara Formations have a chemicalcomposition typical for metasedimentary protolithes andabout 15% for tourmalines grown in granitoids.

The Lower Devonian Cabanillas Group was deposited in apresumably similar plate-tectonic setting to the Ordovicianbasin. This Group is divided into two sediment successionswith different features and location. One succesion (WCo)crops out in the Western Cordillera (near Cabanillas) with athickness of aproximately 1200m. The other succession(CCo) is preserved on the coastal block, unconformably cov-ering the Arequipa Massif and has only a maximum thick-ness of 400 m. Paleocurrent direction is towards the East onthe WCo site and towards the West on the CCo site. The sed-iments from the CCo site are significantly less mature thanthe sediments from the WCo site, as indicated by the nor-mative light mineral content (after recalculation consider-ing the whole rock geochemistry). The CCo sediments con-tain more rock fragments and feldspar and point to an arcsource. This is reinforced by the minor and trace elementcomposition. The average Zr/Sc ratios are 54 and 19 for theWCo and the CCo sites, respectively. This is characteristic fora high degree of recycling at the WCo site and a low degreeof recycling at the CCo site, the latter with values close tothe upper continental crust composition. From the heavymineral and the tourmaline chemical analysis both succes-sion show signatures typical for mature sediments. This isdemonstrated by the high ZTR content (mostly over 90%)and the high content of tourmalines from metasedimenta-ry sources (WCo: 61,5-67,4% CCo: 100%). The well-recyclednature of the Ordovician and Devonian sediments makes itprobable that they originate from a stable inner craton or areycled older orogen. The additional arc signature from theSandia Formation could originate from the contemporane-ous Ordovician arc or could be an older arc signature. Thearc signature of the CCo sediments could be interpreted tosupport the assumption of a Devonian arc in the region ofthe Arequipa Massif. Alternatively it could represent anolder unidentified arc system. We plan to apply LA-ICP-MSdating of detrital zircons to test the different hypothesis.

Geo.Alp, Vol. 4, 2007 77


IINNTTEERRAANNNNUUAALL CCLLIIMMAATTEE VVAARRIIAABBIILLIITTYYRREECCOORRDDEEDD IINN EEAARRLLYY PPLLIIOOCCEENNEE MMOOLLLLUUSSCC SSHHEELLLLSS FFRROOMM CCOOAASSTTAALL PPEERRUU

Lars Reuning1 and Thomas J. DeVries2

1 Institute of Geology, RWTH Aachen University, D-52056 Aachen, Germany; [email protected] Burke Museum of Natural History and Culture, Seattle 98195, USA

The interaction between the El Niño-Southern Oscilla-tion (ENSO) and long-term future global warming is uncertain. Some models link past and future “hothouse”climates to a shallowing of the east Pacific thermoclineand a shift towards a permanent “El Niño-like state” in theeast Pacific. This is in contrast to other models indicatinglittle change in the ENSO system under “hothouse” condi-tions. The early Pliocene, characterized by prolongedglobal warmth, provides a good testing ground for theseconflictive theories. Since ENSO events are tightly coupled to the annual cycle it is essential to use paleocli-mate-archives with seasonal resolution to resolve individ-ual ENSO events. The stable oxygen isotopes of mollusc

shells could provide the first proxy-record for ENSOevents during the early Pliocene. We will evaluate the po-tential of the mollusc species Dosinia ponderosa, fromseveral Pliocene exposures in coastal Peru, as climatearchives. A range of analytical methods (scanning elec-tron microscopy, X-ray diffraction, cathodoluminescence)were applied to develop a screening procedure for diage-netic modifications. Replacement of shell calcite by gyp-sum was identified as the main diagenetic process activein the arid environment of coastal Peru. However, severaldiagenetically unaltered mollusc shells were identifiedand selected for stable isotope analysis of seasonal thetemperature variability.

Geo.Alp, Vol. 4, 200778


SSTTAACCKKEEDD CCYYCCLLIICC SSEEDDIIMMEENNTTAARRYY PPAATTTTEERRNNSSPPRRIIOORR TTOO TTHHEE AARRAABBIIAANN SSHHEELLFF CCOOLLLLAAPPSSEE ((OOLLIIGGOOCCEENNEE//MMIIOOCCEENNEE,, OOMMAANN))

Markus Reuter1, Werner E. Piller1, Mathias Harzhauser2, and Andreas Kroh2

1 Institute of Earth Sciences – Geology and Paleontology, Graz University, Heinrichstr. 26, A-8010 Graz, Austria2 Department of Geology and Palaeontology - Natural History Museum Vienna, Burgring 7 A-1010 Vienna; Austria

The collision of Africa and Eurasia during the Oligo-Miocene and the resultant closure of the marine passagebetween the eastern and western Tethys (TerminalTethyan Event) had far-reaching consequences for thedistribution of shallow water areas and the course ofocean currents. It was therefore one of the major eventsfor the distribution and evolution of terrestrial, as well asmarine faunas during the Cenozoic. The exact timing ofthe Terminal Tethyan Event is thus crucial for palaeobio-geographic questions. In this context, the emersion of theArabian Shelf during the Early Miocene was an importantstep because of a drastic reduction of shallow-waterareas. The collapse of the Arabian Shelf was initiated bythe opening of the Gulf of Aden during the Oligocene. Atthis time an extensive carbonate platform existed on theNE rift shoulder in the area of SE Oman. It emerged duringthe Early Miocene when rifting had ceased and the rift shoulder was uplifted. However, the exact timing of itssubaerial exposure is problematic due to the rarity of age-diagnostic fossils in the restricted shallow-marine envi-ronment, as well as the so far poor knowledge of the in-vertebrate faunas. New taxonomic studies of abundantmollusc faunas and some benthic foraminifers fromOligo-/Miocene sections in SE Oman allow a sequencestratigraphic correlation with the Ru4/Ch1-Ch4/Aq1 low-stands of the Hardenbol et al. (1998) sea-level curve. Itshows that the termination of rifting in the Gulf of Adenmust be back-dated from the middle Burdigalian to thebeginning of the early Aquitanian. Therewith, the area ofSE Oman was a primary area that became emerged andproduced an early permanent restriction of the marine

passage between Africa and Eurasia already during theearly Aquitanian.

For the uppermost part of the sedimentary successionthat developed immediatly before the final emersion ofthe platform, a cyclic alternation of inter- (B) and subtidalenvironments (C) documents a fluctuating relative sea -level at different frequences. Single erosive surfaces withpalaeokarst cavities and caliche crusts separate larger B-Csegments. They display relative long episodes of subaerialexposure and are interpreted to have been formed duringlowstands of 3rd order that emerged the platform. Accord-ingly, they sandwiched a stack of B-C alternations repre-senting a third order sequence. It is composed of shortdeepening cycles (allocycles). Each cycle starts with a succession of a high frequency fluctuating B-C stack, inwhich C members are characterised by their low thicknessand a shoaling trend. Therefore they are suggested to represent inferior autocycles that formed during the low-stands of the high order sequences. A thick C member thatshows an internal deepening follows above. It developedunder rising and high standing sea-level of the higherorder sequence TST. Our depositional model possibly explains why peritidal cycles did not occur in older tertiarydeposits of the Arabian Shelf in Oman although they com-prise shallow marine platform carbonates that are equiv-alent to the C member in facies. It suggests peritidal cyclescould have only developed at the end of the synrift stagewhen the subsidence rate had so far declined that theplatform was elevated into the intertidal zone during sea-level lowstands of higher order.

Geo.Alp, Vol. 4, 2007 79


CCUUPPUULLAASS OOFF TTHHEE MMAALLAACCHHIITTDDOOMM CCAAVVEE ((SSAAUUEERRLLAANNDD//NNRRWW)) –– CCRRYYOOGGEENNIICC SSPPHHEERROOLLIITTHHEESSWWIITTHH UUNNUUSSUUAALL CCAALLCCIITTIICC SSTTRRUUCCTTUURREE AANNDD CC//OO--IISSOOTTOOPPIICC CCOOMMPPOOSSIITTIIOONN

Detlev K. Richter and Dana F.C. Riechelmann

Ruhr-Universität Bochum, Institut für Geologie, Mineralogie und Geophysik, Universitätsstr. 150, 44801 Bochum

The calcitic cupula-spherolithes, first described fromthe Malachitdom cave (Schmidt, 1992) show sizes be-tween 1 mm and 11 mm, and a dish-shaped depression onone side. The concave side of the cupulas is quite smooth,whereas the convex side shows subparallel orientedrhomboedral faces at the end of the calcite fibres.

According to Scanning Electron Microscope (SEM) ob-servations these rhomboedral faces are bent-shaped,which coincides with the results of Electron BackscatterDiffraction (EBSD) analyses. These pigmented single fibresare distinguished by a diverging c-axis orientation withinthe crystals. Beak-shaped spherolithes, which do not havethe characteristic indentation but show the same align-ment of fibres, are counted to the cupulas in the broadersense as they are found next to the real cupulas.

The results of the C/O-isotope analyses of the cupulasshowed #13C-values ranging from –1 to –5 ‰ VPDB and#18O-values between –7 and –14 ‰ VPDB. Within thespherolithes a trend becomes apparent for a lighter O- isotopy and a heavier C-isotopy from the inner to theouter parts. According to "ák et al. (2004) those valuesdiffering significantly from the composition found inother speleothemes, are explained by the formation ofcalcites due to slowly freezing water. During this process,the O-isotopy is mainly affected by the formation of icewhereas the C-isotopy is merely influenced by the degassing of CO2.

The cupula-spherolithes show age ranges from 14.48 ±0.12 kyr to 15.61 ± 0.20 kyr (U/Th-analyses by DenisScholz, Heidelberg). This substantiates a genesis duringthe Weichselian-glacial shortly before the Bölling-inter-stadial. Probably due to a slow climatic warming lastingfor centuries water infiltrated temporary into the cave(lying within the permafrost) and formed an ice-body. Ontop of the ice liquid water form small pools in which cryo-genic calcites formed very slowly (sensu "ák et al., 2004).These were enclosed when the water froze and were latersedimented on the cave floor during the melting of theice.Two remain problems: 1. The Weichselian formation of an icebody could not yet

be proven for the Malachitdom cave. 2. The dish-shaped depression of the real cupulas needs

to be explained.

Schmidt, F. X. (1992): Mineralogische Besonderheitenaus dem Höhlensystem Kreiselhalle Malachitdom. –In: Geologisches Landesamt Nordrhein-Westfalen[Hrsg.]: Der Malachitdom. Ein Beispiel interdisziplinä-rer Höhlenforschung im Sauerland: 91–104; Krefeld.

"ák, K., Urban, J., Cílek, V. & Hercmann, H. (2004): Cryo-genic cave calcite from several Central Europe caves:age, carbon and oxygen isotopes and a genetic model.– Chemical Geology, 206: 119–136; Amsterdam.

Geo.Alp, Vol. 4, 200780


‘‘UUNNDDEERRCCLLAASSTT PPOORREESS’’ FFOORRMMEEDD BBYY SSHHAALLLLOOWWMMOOSSTT GGRROOUUNNDDWWAATTEERR FFLLOOWWDDIISSTTIINNGGUUIISSHH TTOORRRREENNTTIIAALL CCHHAANNNNEELL DDEEPPOOSSIITTSS FFRROOMM DDEEBBRRIISS FFLLOOWWSS

Diethard Sanders

Institute of Geology and Palaeontology, University of Innsbruck, A-6020 Innsbruck, Austria

Underclast pores excavated by very shallow ground-water flow focussed underneath coarse gravels to boul-ders provide a diagnostic criterion to distinguish extreme-ly poorly sorted torrential channel deposits (fluid flow de-posits) from similar-appearing deposits of debris flows.

In the Northern Calcareous Alps, except perhaps formajor trunk valleys, stream-dominated alluvial fans andtalus slopes (many dominated by ephemeral alluvial pro-cesses) represent the main sediment storage in valleys andalong mountain flanks. On the surface of present-day al-luvial fans and talus slopes, the distinction of debris flowsfrom deposits of torrential floods is straightforward. Bycontrast, in many ‘vertical’ outcrops of fan and talus suc-cessions, extremely poorly sorted debris flows may be dif-ficult to distinguish from similar deposits that accumula-ted from torrential fluid flows. With respect to bed geo-metry in outcrop intersection, bed thickness, mean clastsize, sorting, and absence of clast size segregation acrossbeds, both types of deposit appear similar. In addition,both deposits may be vertically associated (often in cut-and-fill patterns) with sediments of unequivocal alluvialorigin, such as sieve deposits. Debris flows and fluid flowsare characterized by different types of downflow imbrica-tion; in two-dimensional outcrops of lithified deposits,however, it is difficult to clearly identify abc-axes of clastsfor distinction of imbrications. Furthermore, in both typesof deposits, imbrication often is absent in outcrop scale.Whereas a primary matrix of carbonate mud to argilla-ceous mud is diagnostic of cohesive debris flows, a matrixof winnowed sand is not a good sole criterion for fluidflow/debris flow distinction.

Inspection of numerous fresh exposures in presently-active stream-dominated fans and torrential streams, in-cluding the days after floods, indicates that in coarse-grained, extremely poorly sorted fluid flow deposits, lar-ger clasts are underlain by a widespread type of pore herecalled ‘underclast pores’. The pores are present immediate-ly below clasts of coarse gravel to boulder size, are limitedin extent to the clast above, are widest near the centralpart of the clast underside, and taper out towards the clastmargins, but also may partly engulf the clast from below.In fresh torrent deposits, closely below the actual sedi-ment surface, many underclast pores are partly or, more

rarely, completely filled by an (net) upward-fining layer afew millimeters to a few centimeters thick of carbonate-lithic sand to carbonate mud. Because of later infiltrationof carbonate mud into the remnant pore space (a wide-spread process in talus and fan deposits of the NCA), in lit-hified deposits, underclast pores commonly are complete-ly clogged by geopetally-laminated sediment. In lithifieddeposits, because of weathering, the sediment-filled for-mer underclast pores may be overlooked if not specificallysearched for. For the interpretation of underclast pores,three observations are significant. (1) In underclast pores,geopetal fillings mainly of silt to mud are widespreadbelow larger clasts where at the surface of the pebbly tobouldery deposit, no sand to mud had accumulated at allor is confined to a few small, thin patches. (2) Underclastpores are limited in presence to (ephemerally active) tor-rential channels on stream-dominated fans and on talusslopes. (3) In these deposystems, underclast pores are limi-ted to sediments of very poor to extremely poor sortingfrom mud to cobbles or boulders.

During flood stage, when a larger clast comes to rest onstream bed, formation of underclast pores starts. Duringpeak to waning flood, because the clast focusses subsur-face flow within the uppermost centimeters of sediment(hyporheic flow of limnology) into a smaller volume thanthe flow within the surrounding sediment, according tothe Law of Stationary Current Flow, below the larger clastshyporheic flow is more rapid than in the surrounding sedi-ment, and finer-grained material underneath the clast isswept out. During waning flood, depending on availabilityof fine-grained sediment, the underclast pore in turn maybecome partly filled by geopetals of fine sand to carbona-te mud. Because of the described conditions of formation,underclast pores can form only in fluid flows, irrespectiveof whether the extremely poorly sorted clastic materialoriginally might have been brought to site by debris flows,and subsequently reworked by torrential floods. In freshdebris flow deposits, no underclast pores were found bythe author. In fully lithified successions, underclast poresthat commonly are completely or partly filled by geope-tally-laminated internal sediments (silt to mud) are an un-equivocal criterion to distinguish extremely poorly sortedtorrential deposits from genuine debris flow deposits.

Geo.Alp, Vol. 4, 2007 81


FFIIRRSSTT OOLLIIGGOOCCEENNEE CCOORRAALL FFAAUUNNAA FFRROOMM TTHHEE EEAASSTTEERRNN AALLPPSS

Diethard Sanders1 and Rosemarie Baron-Szabo2

1 Institute of Geology and Palaeontology, University of Innsbruck, A-6020 Innsbruck, Austria2 Smithsonian Institution, Dept. of Invertebrate Zoology, Washington DC, USA

In the Werlberg Member of the Häring Formation (Rupelian, Northern Calcareous Alps, Austria), in carbon-ate rocks of low-energy rocky to gravelly shores and low-energy lagoonal areas, a coral fauna composed of elevencolonial species has been identified.

During the Rupelian, the area of the future EasternAlps had largely emerged as an elongate island betweenthe Mediterranean Sea in the south and the Paratethys inthe north. The Häring Formation is part of the inner-Alpine Tertiary, and accumulated during Oligocene basinformation along the Inn Valley strike-slip fault (cf. Ortner& Stingl, 2001). Today, in the Eastern Alps, Oligocene shal-low neritic rocks are very scarcely preserved.

The Werlberg Member consists mainly of pure shallow-water limestones, and formed during transgression over atruncated substrate of folded and faulted Triassic car -bonate rocks. In the basal part of the member, a gradualvertical transition from local rhegolithic breccias into thin intervals of beachface breccias, a persistent matrix of limemudstone in textures of bio-lithoclastic floatstone andwackestone, abundant carbonate rock gravels to cobblesof extremely angular shape because of densely-spacedmacroborings, and in-situ preserved thickets of branchedcoralline algae and/or of branched corals all record low-energy conditions along the marine transgressive fringe.The carbonate lithoclasts are derived from the local rocksubstrate, and are densely riddled by borings oflithophagids and clionids. The lithoclasts are overgrownby sessile foraminifera, serpulids, vermetids and balanids.In addition, punctate brachiopods are common, and mayhave thrived attached to hard substrata. Higher up- section, the Werlberg Member may locally contain bio-clastic wacke-packstones rich in benthic foraminifera,coralline algae and fragments of branched cyclostomatebryozoans. At a single location, the member includes apackage of bioclastic wackestones to floatstones rich incorals; these limestones probably accumulated from a

low-energy shallow subtidal lagoon. The Werlberg mem-ber is capped by an intra-Oligocene unconformity thatformed upon subaerial exposure.

In the intervals that accumulated along the rocky togravelly carbonate shore, the corals most commonly arecoarsely fragmented. In the interval deposited from anoverall quiet shallow subtidal setting (lagoon or shelteredinnermost shelf), however, integer coral colonies up to afew decimeters in size are common. No reef structure wasobserved. The corals thrived isolated and in level-bottoms.The coral fauna of the Werlberg Member includes tengenera, and is dominated by genera of large age range(mainly Paleocene to Miocene). The fauna shows highestaffinity to both Central European and Caribbean-CentralAmerican faunas. On the species level, the Werlberg faunacorresponds best with Oligocene faunas from the circum-Mediterranean domain, in particular with that of the„Lessini shelf“ of the Southern Alps. Two species of thefauna (Syzygophyllia brevis, Stylocoenia carryensis) areidentified for the first time in pre-Miocene rocks. TheWerlberg fauna consists of, both, branched coral taxa(phaceloid, ramose, ?dendroid) and of massive formsmainly of cerioid, meandroid, and plocoid integration. Nosolitary corals were found. Compared to recent coral fau-nas of similar low-energy depositional settings, the Werl-berg fauna is of similar to higher diversity. Also, the widespectrum of coral growth forms, polyp integrations andpolypar size underscores that, overall, the Oligocenecorals were not subject to elevated ecostress other thanpotential stress factors that pertain to every shallow sub-tidal nearshore setting.

Ortner, H. & Stingl, V., 2001, Facies and basin develop-ment of the Oligocene in the Lower Inn Valley,Tyrol/Bavaria. – In: Piller, W. E., Rasser, M. W., Eds., Pa-leogene of the Eastern Alps. Österr. Akad. Wiss.,Schriftenr. Erdwiss. Komm., 14, 153–196, Vienna.

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BBIIOO--IINNDDUUCCEEDD CCAALLCCIIUUMM CCAARRBBOONNAATTEE PPRREECCIIPPIITTAATTIIOONN IINN EEAASSTTEERRNN AALLPPIINNEE SSPPRRIINNGG TTUUFFAASS

Diethard Sanders1, Doris Gesierich2, and Eugen Rott2

1 Institute of Geology and Palaeontology, University of Innsbruck, Austria2 Institute of Botany, University of Innsbruck, Austria

In Alpine tufa-precipitating springs cyanobacteria,micro- and macroalgae and moss directly induce or indi-rectly favour the precipitation of a major portion of totalcalcium carbonate. Other precipitates such as flowstonesand pore-filling cements of calcite or aragonite overall areinsignificant with respect to volume.

In all investigated tufas, calcium carbonate formed inassociation with microbes represents a significant toprevalent precipitate that forms first or very early in dia-genetic succession. Among the microbes involved in tufaformation, filamentous cyanobacteria, the coccoiddesmid Oocardium, filamentous chlorophytes and di-atoms are important, in variable relative amounts. The filamentous cyanobacterium Rivularia shows a wide spec-trum of calcification, ranging from scattered isolatedcrystals to layers of merged crystals, to complete calcifica-tion of filament sheaths in large crystals up to about 10mm in size of calcite. Other filamentous cyanobacteria (e.g. Scytonema, Petalonema, Calothrix, Phormidium) wereobserved to induce precipitation of micro- to orthosparit-ic crystal aggregates. For these cyanobacteria, the style ofcalcification seems to depend mainly on the tufa-precipi-tating potential of the water, such that the resulting microfacies may range from porous aggregates of microsparite to small-crystallite sparite to well-calcifiedfabrics with the outline of the former cyanobacterialcolony well recognizable. A similar style and range of cal-cification was observed for filamentous zygnemaleans(e.g. Zygnema, Mougeotia). Overall, however, filamentouszygnemaleans seem to be of minor significance in tufaformation.

The simple coenobia-forming desmid Oocardiumshows a specific style of calcium carbonate precipitationby forming a calcite ring in the proximity of the immedi-ate cell environment. Concomitant with calcite precipita-tion, the alga moves up, leaving a tube of mucilage sur-rounded by calcite behind. Fresh, unaltered calcite tubesshow a circular outline, and appear to grow upward on‘step-dislocation like’ facets. The precise mode of calciteprecipitation immediately adjacent to Oocardium cells,however, as yet is poorly documented. By this style of

crystallization, laminae of tufa up to nearly 10 mm inthickness per growth season (spring-autumn) can beformed. The initial crystal shape of Oocardium tufa, how-ever, is highly unstable; combined recrystallization andfurther calcite crystallization starts within weeks tomonths after initial formation. Without knowledge of ini-tial growth form, the resulting microfabric of very large(up to > 10 mm) single crystals of „combispar“ calcite(with relicts of Oocardium growth tubes) may be difficultto recognize in its origin. In diatom mats, precipitation ofdensely-spaced but initially isolated calcite micro- to or-thospar crystals is induced. The calcite crystals show a setof shapes that perhaps result from different influences(diffusion, fluid transport) during crystallization. Individ-ual diatom frustules may provide a crystallization centerto a calcite crystal. Because some diatoms grow in firmmats, the resulting layer of orthosparitic calcite may appear as a cement fringe in field and polished slab, yetowes its first origin to growth of numerous calcite crystalswithin a densely-populated diatom mat.

Among the macroalgae, the xanthophyte Vaucheriagives rise to a specific microfacies. This alga calcifies byprogressive nucleation, growth and merging of calcitecrystals (mainly well-defined rhombohedra) directly on itssurface, until the entire algal filament is encased bymicro- to orthospar calcite. Vaucheria tufa prevails on afew waterfalls, but typically is present in minor amounts.With respect to their initial calcification, moss plants mayshow (a) a coating of orthospar calcite, (b) a coating ofmicrite, (c) a coating of micropeloids, (d) large orthosparcrystals on the tips of leaves and/or at the basis of leaves,(e) calcification of cyanoids (e. g. Rivularia) or Oocardiumsettled on the moss, and (f) combinations of (a) to (e). Weguess that the role of moss primarily is a passive one. Byproviding a large surface area for water spray and forevaporation, as well as by providing a settlement area tomicroalgae which, in turn, can induce calcification, mosstufts favour calcium carbonate precipitation. We couldnot identify a specific type of calcium carbonate crys-tallisate exclusively tied to moss plants; this underscoresthat the role of moss rests mainly in its large differentiat-ed surface rather than in physiological traits.

Geo.Alp, Vol. 4, 2007 83


IINN VVIIVVOO CCAALLCCIIFFIICCAATTIIOONN OOFF VVAAUUCCHHEERRIIAA ((XXAANNTTHHOOPPHHYYCCEEAAEE))IINN TTUUFFAA--PPRREECCIIPPIITTAATTIINNGG SSPPRRIINNGGSS OOFF TTHHEE EEAASSTTEERRNN AALLPPSS

Diethard Sanders1, Doris Gesierich2, and Eugen Rott2

1 Institute of Geology and Palaeontology, University of Innsbruck, Austria2 Institute of Botany, University of Innsbruck, Austria

In Alpine tufa-precipitating creeks, the macroalgaVaucheria calcifies in vivo by progressive growth of calciterhombohedra directly on the surface of the alga. Calcifi-cation of this alga results in a distinct microfacies ob-served in both active and fossil Alpine waterfall tufas.

Vaucheria is a xanthophycean macroalga common insprings, streams and rivers of temperate latitudes. Exceptin waters sufficiently supersaturated for calcium car -bonate, this alga does not calcify. The calcification thuspertains to the induced type of biocalcification. In tufa-depositing creeks of the Alps, in low and mid-altitudes,mainly in waterfalls and in cascading reaches Vaucheria isfairly common. In these systems, the alga prefers well-litlocations subject to swift and persistent water flow, andforms dense monospecific tufts.

Calcification starts in the proximal (older) parts ofalgal filaments, by nucleation and growth of calciterhombohedra directly on the surface of the alga. Inmost cases, the calcite crystals are of perfect or nearlyperfect rhombohedral shape. In early stage of calcifica-tion, the calcite rhombohedra are loosely scattered overthe surface of the alga. Progressive growth of rhombo-hedra coupled with continued nucleation of new calcitecrystals in between results in a coating of the algal fila-ment by a dense „crystal carpet“. In late stage of calcifi-cation, the crystals merge with each other along com-petitive boundaries, resulting in a rigid tube in whichthe algal filament is completely encased. In standard

light microscopy, the calcite crystals begin to be readilyrecognizable when they had attained microspar size,and they terminate their growth when they had attained a size of about 50-200 microns. We found noevidence for mediation of this style of calcification byother organisms. Although, in some cases, epiphytic diatoms and cyanobacteria were observed on partly calcified filaments of Vaucheria, these organisms clear-ly are not involved in nucleation and growth of the cal-cite crystals directly on the surface of the filaments.Complete encasement of algal filaments by calcite mayimpede the metabolic activity of the plant. As a result,the algal filaments die off in their proximal parts whilecontinue to grow in the distal parts, leaving behind theempty crystal tubes of the former algal filament. Because Vaucheria grows in dense tufts and meadows, aspecific type of cementstone microfacies is produced bythe calcification of this alga.

In waterfalls, combined downward growth and con-temporaneous calcification of Vaucheria may result inbizarrely-shaped, very delicate tufa curtains raging out. Inthin section, these tufa curtains consist entirely ofVaucheria cementstone. In the shaded understorey of thetufa curtains, other organisms such as moss and/orcyanobacteria may thrive and calcify, giving rise to differ-ent microfacies. On the brink of creek cascades and onsteep to vertical water-run surfaces, dense stands of thisalga may form knobs that, in the resulting tufa, appear asthe characteristic cementstone microfacies.

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BBAACCIINNEELLLLAA--TTYYPPEE FFIILLAAMMEENNTT SSTTRRUUCCTTUURREESSIINN UUPPPPEERR CCRREETTAACCEEOOUUSS SSHHOORREE ZZOONNEE DDEEPPOOSSIITTSS ((LLOOWWEERR GGOOSSAAUU SSUUBBGGRROOUUPP,, AAUUSSTTRRIIAA//GGEERRMMAANNYY))

Felix Schlagintweit1, Diethard Sanders2, and Hans-Jürgen Gawlick1

1 Montanuniversität Leoben, Department für Angewandte Geowissenschaften und Geophysik: Lehrstuhl Prospektion und Ange-wandte Sedimentologie, Peter-Tunner-Straße 5, A-8700 Leoben

2 Institut für Geologie und Paläontologie, Fakultät für Geo- und Atmosphärenwissenschaften, Universität Innsbruck,Innrain 52, A-6020 Innsbruck

Bacinella irregularis Radoi#i# is a widespread MiddleTriassic to Late Cretaceous micro-encruster of uncleartaxonomic affiliation. B. irregularis consists of an aggre-gation of hollow chambers of erratic, irregular shape thatare bounded by thin walls of micrite. It is reported mainlyfrom reefal, peri-reefal and lagoonal habitats, where itprevalently encrusts bio- and lithoclasts, or occupiescrevices (e. g. crevices on the outer side of shells, skeletonsor tests) and cryptic habitats either in interstitial pores orin intraparticle pores (e.g. skeletal pores, borings).Bacinella-like „cell aggregates“ known as alveolar texturealso are present in terrestrial caliche carbonates. Withinsoils, alveolar texture may result from calcification offungi in association with microbes, or from microbial aggregates. In the marine environment, most plausible in-terpretations of Bacinella-fabrics refer to microbes(cyanobacteria or micro-algae?), sessile foraminifera, orsponges.

At Mount Untersberg near Salzburg (Austria), a trun-cated substrate of Upper Jurassic Plassen Limestone isunconformably overlain by shore zone deposits („Unters-berger Marmor“) that comprise the basal part of an UpperCretaceous succession (Lower Gosau Subgroup). The Un-tersberger Marmor is interpreted as a deposit of subma-rine debris aprons ahead of wave-dominated, transgres-sive gravelly to rocky carbonate shores. In samples of Un-tersberger Marmor from quarry Wallinger (Gröding/Salzburg), Bacinella-type structures were observed inmixed carbonate-lithic/bioclastic grainstones, as a bridg-

ing between individual litho- and bioclasts. Bioclasts include rare small arenaceous and rotaliid foraminifera,debris of coralline algae, serpulids, bryozoans and a largeencrusting foraminifer (> 5 mm) with similar appearanceof some morphotypes of Lithocodium aggregatum Elliott. In thin section, the straight to slightly curved mi-critic walls (width: ~ 0.02 mm) of the Bacinella-type fab-rics connect sand grains, resulting in a compartmental-ized „pseudo-cell“ structure defined both by the grainsand the micritic walls between. Some carbonate clastsshow irregular surfaces with penetration of Bacinella-type structure into the clast, suggesting potential capa-bility of boring. Aside of Mount Untersberg, grain-bind-ing/encrusting Bacinella-type structures and cf. Litho -codium were found also in other successions of Unters-berger Marmor, together with a bioclast spectrum char-acterized by coralline algae, sessile arenaceous and ro-taliine foraminifera, branched bryozoans, serpulids, and(in the basalmost part) brachiopods and echinoid frag-ments. Conversely, rudist fragments are rare to absent,and colonial corals are extremely rare to most commonlyabsent. Our observations document the previously unreported presence of binding/encrusting Bacinella-type organisms in sandy to gravelly shore zone deposits.In comparison to other palaeoenvironments whereBacinella-type fabrics were reported, the overall abrasiveshore zone depositional setting of the Untersberger Marmor represents an environment wherein sediment-binding organisms overall are scarce.

Geo.Alp, Vol. 4, 2007 85


KKAARRTTEE DDEERR TTRRIINNKKBBAARREENN TTIIEEFFEENNGGRRUUNNDDWWAASSSSEERR ÖÖSSTTEERRRREEIICCHHSS 11::550000..000000

Gerhard Schubert1, Rudolf Berka1 und Rudolf Philippitsch2

1 Geologische Bundesanstalt, Abteilung Hydrogeologie2 Bundesministerium für Land- und Forstwirtschaft, Umwelt und Wasserwirtschaft Abteilung VII 1, Nationale Wasserwirtschaft

In einigen Gegenden Österreichs ist die Wasserversor-gung mangels geeigneter Alternativen auf trinkbares Tiefengrundwasser angewiesen – dies trifft im Besonde-ren auf Teile des Inn- und Hausruckviertels, die Oststeier-mark und das Südburgenland zu. Diese Tiefengrundwässersind aber auch aufgrund ihrer Verweilzeit und des damitverbundenen Schutzes vor Verunreinigungen von wasser-wirtschaftlicher Bedeutung – nämlich in Hinblick auf eineTrinkwassernotversorgung. Sie stellen wegen ihrer langenVerweilzeit eine Grundwasserreserve sowohl für nieder-schlagsarme Perioden als auch im Falle einer Verunreini-gung der oberflächennahen Grundwässer dar.

Da die gegenständlichen Tiefengrundwässer durchVersickerung von Oberflächenwasser und Niederschlagnur langsam erneuert werden, besteht für sie die Gefahreiner Übernutzung – vor allem, weil die Tiefengrundwäs-ser häufig für Einzelwasserversorgungen mit Brunnen erschlossen werden, deren technisch unzureichender Aus-bau das ungenützte Auslaufen des unter Druck stehendenTiefengrundwassers nicht verhindert. Dem wird durch dasErrichten von technisch aufwendigen zentralen Wasser-versorgungsanlagen entgegengewirkt.

Ende 2005 beauftragte das Bundesministerium fürLand- und Forstwirtschaft, Umwelt und Wasserwirtschaftdie Geologische Bundesanstalt mit der Erstellung einerösterreichweiten Übersichtsdarstellung der als Trinkwas-ser nutzbaren Tiefengrundwasservorkommen. Ende 2006wurde dazu ein Bericht inklusive einem umfangreichen Literaturverzeichnis, Detailkärtchen, Schnitten und einerÜbersichtskarte im Maßstab 1:500.000 erstellt (Berka, R.& Schubert, G., 2006: Trinkbare Tiefengrundwässer inÖsterreich. – Unpublizierter Bericht, Geologische Bundes-anstalt, Wien). Im Bericht werden die hydrogeologischenGegebenheiten der verschiedenen Vorkommen näher er-läutert und exemplarisch die chemische und isotopenhy-drologische Beschaffenheit dieser Wässer dargestellt.

Die im Rahmen des Projekts erarbeitete Übersichts -karte 1:500.000 wird nun weiter kartographisch bearbei-tet und soll gemeinsam mit Erläuterungen publiziert wer-den. Hauptaugenmerk liegt auf der detaillierten Darstel-lung der großen tertiären Sedimentbecken, an welche derGroßteil der trinkbaren Tiefengrundwässer gebunden ist.Diese Übersichtskarte zeigt als Besonderheit österreich-weit die Verbreitung der stratigraphischen Stufen der ter-tiären Sedimente in abgedeckter Form.

Geo.Alp, Vol. 4, 200786


TTHHEE IIMMPPAACCTT OONN TTHHEE LLIITTHHOO-- AANNDD BBIIOOFFAACCIIAALL DDEEVVEELLOOPPMMEENNTT OOFF TTHHEE MMIIDD DDEEVVOONNIIAANNKKAA!!AAÁÁKK EEVVEENNTT IINN TTHHEE PPRRAAGGUUEE BBAASSIINN,, TTHHEE GGRRAAZZ PPAALLAAEEOOZZOOIICC AANNDD TTHHEE CCAARRNNIICC AALLPPSS

Thomas J. Suttner1 and Stanislava Berkyova2

1 Commission for the Palaeontological and Stratigraphical Research of Austria c/o University of Graz, Institute of Earth Sciences(Geology and Palaeontology), Heinrichstrasse 26, A-8010 Graz; [email protected]

2 Czech Geological Survey, Geologická 6, 15200 Praha 5, Czech Republic; [email protected]

The Ka#ák Event, named by House (1985), is one of 3globally documented Mid Devonian events (Chote#, Ka#ákand pumilio Event). It is interpreted as a transgressive event(correlated to the Ie cycle of Johnson et al., 1985) andranges from the upper part of the kockelianus to the lowerpart of the hemiansatus conodont Zone. Extensive extinc-tion, substantial reduction in diversity of pelagic and ben-thic fauna globally, as well as appearance of new faunal ele-ments is characteristic for the Ka#ák Event. Furthermore, ithas played a significant role in evolution of some major fos-sils groups, such as are: goniatites, trilobites, brachiopodsand conodonts (House, 2002; Walliser, 2000). A densely plotof carbon isotope values has recently been given by Bug-gisch and Joachimski (2006) for the entire Devonian. Theirstudies reveal a positive carbon excursion from less than2‰ up to nearly 3.0‰ at the critical time interval.

PPrraagguuee BBaassiinn:: Here the Ka#ák Event shows one of thesharpest stratigraphical and lithological boundaries in theBarrandian area. It is represented by the onset of dark cal-careous shale of the Ka#ák Shale Member (Srbsko Forma-tion) sharply overlying the limestones of the Chote# Forma-tion (Eifelian). In more proximal sequences of theKon%prusy area (Jirásek section), a dark grey bituminouslimestone interval of less than 1 m occurs, which is regardedby some authors as an equivalent of the Ka#ák shales. How-ever it has to be stated that this correlation is not that clear,because Nowakia otomari started earlier than the onset ofblack shales (as well as Cabrieroceras rouvillei/crispiforme).

Although the planktonic and nektonic elements wereless affected, the decline in their diversity was remarkable.In Prague Basin, about 250 species are described from theChote# Formation but only about 60 from the Ka#ák Mem-ber (Chlupá# and Kukal, 1986).

GGrraazz PPaallaaeeoozzooiicc:: The pelagic deposits of the GrazPalaeozoic during the middle to upper Eifelian are repre-sented by the St. Jakob Formation (Laufnitzdorf Nappe).The sequence consists of tentaculite bearing limestonesand lydites with inter-beds of immature sandstones. Theshallow marine equivalent to the pelagic development can

be found in the Rannach Nappe (Plabutsch Formation)where a highly diverse carbonate fauna (including stro-matoporoids, corals, and brachiopods) developed out of abenthic pioneer community in the course of the transgres-sive phase.

CCaarrnniicc AAllppss:: In the Carnic Alps the discussed event is represented by a lithological change from limestones toblack shales and lydites within distal slope settings (Ober-buchach II section). In shallow water environments of theKellerwand Nappe (Spinotti Formation) the mid to late Eife-lian transgression results in a change from massive birds -eyes limestones (lagoonal to peritidal settings) to thick bed-ded peloidal limestones (approx. mid to deeper shelf set-tings). But due to lacking biostratigraphic constraints, it isnot clear, whether this change reflects Ka#ák Event- deposits or not.

This is a contribution to IGCP 497 and projectKJB307020602.

Buggisch, W. & Joachimski, M.M. (2006): Carbon isotopestratigraphy of the Devonian of Central and South Eu-rope. – Paleogeography, Paleoclimatology and Paleoe-cology, 240: 68–88.

Chlupá#, I. & Kukal, Z. (1986): Reflection of possible globalDevonian events in the Barrandian area, C.S.S.R., In: Lecture Note in Earth Sciences, Global Bio-events, O.Walliser (ed.), 169-179, Springer-Verlag, Berlin.

House, M.R. (1985): Correlation of mid-Palaeozoic am-monoid evolutionary events with global sedimentaryperturbations. – Nature, 313: 17–22.

House, M.R. (2002): Strength, timing, setting and cause ofMid-Palaeozoic extinctions. – Paleogeography, Paleocli-matology and Paleoecology 218: 5–25.

Johnson, J.G., Klapper, G. & Sandberg, C.A. (1985): Devonianeustatic fluctuations in Euramerica. – Geol. Soc. Amer.Bull., 96: 567–587.

Walliser, O.H. (2000): The Eifelian–Givetian boundary. –Courier Forsch. Inst. Senckenberg, 225: 33–47.

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DDEEPPOOSSIITTIIOONNAALL EENNVVIIRROONNMMEENNTT OOFF CCRREETTAACCEEOOUUSS SSEEDDIIMMEENNTTSSOOFF TTHHEE CCHHIIKKKKIIMM SSYYNNCCLLIINNEE ((SSPPIITTII,, NNOORRTTHHEERRNN IINNDDIIAA))

Thomas J. Suttner1, Rufus J. Bertle2, and Alexander Lukeneder3

1 Austrian Academy of Sciences, Commission for the Palaeontological and Stratigraphical Research of Austria c/o University ofGraz, Institute of Earth Sciences (Geology and Palaeontology), Heinrichstrasse 26, A-8010 Graz, Austria;[email protected]

2 GEOGNOS Bertle ZT GmbH, Kronengasse 6, A–6780 Schruns, Austria; [email protected] Natural History Museum Vienna, Department of Geology and Palaeontology, Burgring 7, A-1010 Vienna, Austria;

[email protected]

The Cretaceous sequence of the Chikkim Syncline(Tethys Himalaya, northern India) is represented by the Giu-mal and Chikkim formations. The age of the Giumal Forma-tion in Spiti is expected to be Lower Cretaceous in age by arecently discovered ammonoid fauna (Lukeneder et al., inprep.) and by planktonic foraminifera of the Chikkim For-mation constraining the latter to range between Late Al-bian and Campanian (Bertle and Suttner, 2005).

The Giumal Formation measures about 350 m and con-sists of brown coloured sandstone and dark shale. Five cy-cles could be distinguished within the succession, ofwhich each starts with a several metres thick interval ofblack shale intercalated by single beds of fine grainedquartz arenites. Along the cycle, sandstone beds becomemore abundant and increased in thickness (decimetre-bedded), forming 10 to 40 metres thick intervals towardsthe top. Thickening upward of the beds as well as coarsen-ing upward is observed in each cycle. Usually the upper-most bed of the sandstone-interval is composed of coarsegrained matrix with several layers of disarticulated bi-valve shells intercalated. While fine grained sandstonebeds have a dark, micritic matrix, topmost coarse grainedarenites are mature. Sandstone beds contain highamounts of quartz, yield glauconite grains and limoniticclasts. In the lower part of the sandstone-intervals of

cycle 2 and 5, ammonoids occur, comprising well pre-served planspiral and criocone shell-types.

The Giumal Formation is overlain by the carbonatic se-quence of the Chikkim Formation (minimum thickness: 65m). The base of the Chikkim Formation starts with a rela-tively sharp contact of well bedded micritic carbonates toa strongly weathered interval of grey calcareous shale ofthe uppermost part of the Giumal Formation. Within theoccurrence of the first limestone beds planktonic fora -minifera occur (e.g., Planomalina buxtorfi and Rotaliporaappenninica). Microfacies changes at the boundary of theLower to the Upper Chikkim Member, where micritic lime-stone beds (20 cm in thickness) are replaced by thin-bed-ded carbonaceous marls.

The observed cyclicity of the Giumal Formation mostprobably represents a siliciclastic slope facies with distalto proximal turbidite fans. Micritic limestones, rich inplanktonic foraminifera, hint to pelagic settings, at leastfor the deposits of the Lower Chikkim Member.

Bertle, R.J. & Suttner, T.J. (2005): New biostratigraphicdata for the Chikkim Formation (Cretaceous, TethyanHimalaya, India). – Cretaceous Research, 26 (6):882–894.

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MMIICCRROOFFAACCIIEESS OOFF TTHHEE HHOONNGGGGUULLEELLEENNGG FFOORRMMAATTIIOONN ((LLAATTEE DDEEVVOONNIIAANN,, NNWW XXIINNJJIIAANNGG,, CCHHIINNAA))

Thomas J. Suttner1, Xiuqin Chen2, Ruth Mawson3 and John A. Talent3

1 Austrian Academy of Sciences, Commission for Palaeontological and Stratigraphical Research of Austria c/o University of Graz,Institute of Earth Sciences (Geology and Palaeontology), Heinrichstrasse 26, A-8010 Graz, Austria; [email protected]

2 Chinese Academy of Sciences, Nanjing Institute of Geology and Palaeontology, Department of Invertebrate Palaeontology,39 East Beijing Road, Nanjing 210008, China; [email protected]

3 Department of Earth and Planetary Sciences, Macquarie University, NSW 2109, Australia;[email protected], [email protected]

The type section of the Hongguleleng Formation, atthe Boulongour Reservoir close to the small village of Sa-montoma, is one of six Late Devonian sections (Boulon-gour, Genaren, Qiligoa, Emuha, Aoroa and HebukeheRiver) in the northernmost Uygur Autonomous Region ofXinjiang, chosen for evaluation of the impact of the UpperKellwasser Event at the Frasnian-Famennian boundary.

At the Boulongour Reservoir, the uppermost part ofthe subjacent Zhulumute Formation consists of volcano -clastic sediments with some beds bearing plant remains.The grain size of the tuffaceous beds at the formationboundary decreases from sand/silt to shale with the firstbed of the Hongguleleng Formation forming the base of abioclast-dominated calcareous depositional environment(Xia, 1997).

The formation is divided into two units on the basis ofsedimentary characteristics. Unit 1 (approx. 64 m) consistsof limestone beds (wacke- to packstone) yielding brachio-pod-rich layers with subordinate bryozoans, ostracodsand crinoid debris at the base. The fossil diversity increasesa few metres above the base of the formation withcrinoids and bryozoans becoming the major components;clasts of spiculite occur in some beds. Limestone beds(wacke- to grainstone), generally 1–15 cm thick, alternatewith fine grained mudstones from a few cms (middle partof Unit 1) to a maximum of 200 cm (lower and upperthird). The upper part of the unit is characterized by layersof carbonate nodules (composed mainly of spiculite mud-stones or pelmicritic wackestones) rather that continuityof limestone beds. Cephala of phacopid trilobites areprominent in some limestone nodules.

The first laterally continuous limestone bed above thelatter horizon marks the base of Unit 2 (total thickness:

32 m). As in Unit 1, it consists of limestone beds alternat-ing with shale intervals, though with alteration more con-stant. Beds usually do not reach a thickness greater than3–5 cm. Inter-bedded mudstone horizons have an averagethickness c. 20 cm. The microfacies is dominated by fine-grained peloidal limestones with thin layers of crinoidaldebris and sparsely distributed brachiopod and trilobiteshells, as well as crinoidal wacke- to packstones (withskeletal grains of non-crinoidal invertebrates subordi-nate). As the top of the unit is approached, the micriticfraction of the matrix increases.

The sequence is continued above the HonggulelengFormation by an approximately 100 m sequence of greensiliceous and purple silty/sandy mudstones to be discrimi-nated as the Samontoma Formation, named after Samon-toma village. This interval has intercalations up to a fewmetres in thickness of thick-bedded crinoidal grainstones;prominent among these is the low, crinoid- and blastoid-rich ridge referred to as Blastoid Hill by Waters et al.(2003).

Waters, J.A., Maples, C.G., Lane, N.G., Marcus, S., Liao, Z.T.,Liu, L., Hou, H.F. & Wang, J.X. (2003): A quadrupling ofFamennian pelmatozoan diversity: New Late Devoni-an blastoids and crinoids from northwest China. –Journal of Paleontology, 77(5): 922–948.

Xia, F.S. (1997): Marine microfaunas (bryozoans, cono -donts and microvertebrate remains) from the Frasni-an-Famennian interval in northwestern JunggarBasin of Xinjiang in China. – Beiträge zur Paläonto -logie, 22: 91–207.

Geo.Alp, Vol. 4, 2007 89


OONN TTHHEE AAGGEE OOFF TTHHEE SSUURRRROOUUNNDDIINNGG SSIILLIICCEEOOUUSS LLIIMMEESSTTOONNEE OOFF TTHHEEHHAALLLLSSTTÄÄTTTTEERR SSAALLZZBBEERRGG,, NNOORRTTHHEERRNN CCAALLCCAARREEOOUUSS AALLPPSS ((AAUUSSTTRRIIAA))

Hisashi Suzuki and Hans-Jürgen Gawlick

Department Angewandte Geowissenschaften und Geophysik, Montanuniversität Leoben,Peter-Tunner-Str. 5, A-8700 Leoben, Austria

In the Northern Calcareous Alps, salt deposits ofPermo-Triassic age are distributed and excavated. The tec-tonic position of these salt deposits is discussed very con-troversially as in situ (v. HAUER 1857, MOJSISCOVICS 1905) ortransported (HAHN 1913, GAWLICK et al. 2001) (summarisedin TOLLMANN 1985, GAWLICK et al. 2001). One of the keypoints to solve the question of the emplacement of theAlpine salt deposits is to date the surrounding sedimenta-ry rocks (siliceous limestone to siliceous marls). We exam-ine, therefore, the radiolarian age of one sample (BNU)that derives from the end of the borehole BHTNU 040bored at the Halstätter Salzberg in the Salzkammergutarea. The sample BNU is a dark grey laminated siliceouslimestone, in which most radiolarian tests are calcifiedand few ones are preserved as quartz.

Until now the following radiolarians are identified: Ar-chaeodictyomitra rigida PESSAGNO, 1977; Cinguloturriscarpatica DUMITRICA, 1982; C. cf. cylindra KEMKIN & RUDENKO,1993; Cyrtocapsa mastoidea YAO, 1979; Dictyomitrellakamoensis MIZUTANI & KIDO, 1983; Eucyrtidiellum circum-perforatum CHIARI et al., 2002; E. ptyctum (RIEDEL & SANFIL-IPPO, 1974); E. unumaense (YAO, 1979); Gongylothoraxfavosus DUMITRICA, 1970; G. aff. favosus DUMITRICA, 1970;Gongylothorax sp. C sensu SUZUKI & GAWLICK, 2003; Hsuumbrevicostatum (OZVOLDOVA, 1975); H. maxwelli PESSAGNO,1977; Loopus doliolum DUMITRICA, 1997; Neorelumbra sk-enderbegi (CHIARI et al., 2002); Parahsuum sp. S sensu MAT-SUOKA 1986; Parvicingula cappa CORTESE, 1993; Praewil-liriedellum spinosum KOZUR, 1984; Praezhamoidellumbuekkense KOZUR, 1984; Protunuma matsuokai (SASHIDA,1999); Podobursa nodosa (CHIARI et al., 2002); Quarticellaovalis TAKEMURA, 1986; Saitoum levium DE WEVER, 1981;Spongocapsula sp. A sensu SUZUKI & GAWLICK, 2003; Sti-chomitra annibill KOCHER, 1981; Stichocapsa convexa YAO,1979; S. himedaruma AITA, 1987; S. japonica YAO, 1979; S.tegiminis YAO, 1979; S. naradaniensis MATSUOKA, 1984; Sti-chocapsa sp. E sensu BAUMGARTNER et al., 1995; Theocap-somma cordis KOCHER, 1981; Th. medvednicensis GORICAN,1999; Tricolocapsa conexa MATSUOKA, 1983; Tr. fusiformisYAO, 1979; Tr. plicarum YAO, 1979; Tr. tetragona MATSUOKA,1983; Tr. undulata (HEITZER, 1930); Tr. sp. S sensu BAUM-GARTNER et al. 1995; Triversus hexagonatus (HEITZER, 1930);Triversus hungaricus (KOZUR, 1985), Unuma typicus

ICHIKAWA & YAO, 1976; Williriedellum crystallinum DUMITRI-CA, 1970; W. dierschei SUZUKI & GAWLICK, 2004; Williriedel-lum sp. A sensu MATSUOKA, 1983; Zhamoidellum ovum DU-MITRICA, 1970; Z. ventricosum DUMITRICA, 1970.

This fauna resembles that from the Brielgraben whichis dated with ammonites as a Middle Callovian (SUZUKI &GAWLICK 2006), and it is included in the Protunuma lanosussubzone in the Zhamoidellum ovum zone after SUZUKI &GAWLICK (2003). To correlate with the Japanese radiolarianzone, some important species can be mentioned, whichindicate a horizon around the boundary between Tricolo-capsa plicarum and Tr. conexa zones: Cyrtocapsa mas-toidea, Tricolocapsa plicarum, Tr. conexa, Tr. fusiformis, Tr.tetragona, E. ptyctum (MATSUOKA 1983, 1995). AlthoughTricolocapsa aff. fusiformis sensu MATSUOKA 1983 that hasa smaller basal appendage than typical T. fusiformis iscommonly included in the samples from Brielgraben ofthe Middle Callovian, it has not so far been found in BNUof Hallstätter Salzberg. Taking the occurrence of Z. ovum,S. annibill and G. favosus into consideration, the horizonof the sample BNU is located above the lowermost Callov-ian (SUZUKI et al. 2001, SUZUKI & GAWLICK 2003). Therefore,the horizon of BNU lies in the Lower or Middle Callovian.

Gawlick, H.-J., Lein, R., Schlagintweit, F., Suzuki, H. & We-gerer, E. (2001): Berichte Geol. B.-A. 56: 45–49, Wien.

Hahn, F.F. (1913): Mitt. Geol. Ges. Wien 6: 238–357 und374–501, Wien.

Hauer, M.V. v. (1857): Sitzungsb. math.-natw. Kl., Akad.der Wiss., 25: 253-348, Wien.

Matsuoka, A. (1983): J. Geosci., Osaka City Univ. 26:1–48, Osaka.

Matsuoka, A. (1995): Isl. Arc 4: 140–153, Tokyo.Mojsisovics, E. v. (1905): Geol. Reichsanstalt, 1-60, Wien.Suzuki, H. & Gawlick, H.-J. (2003): Gmundner Geostud.

2: 115–122, Gmunden.Suzuki, H. & Gawlick, H.-J. (2006): Abstr. 113th Ann. Mee-

ting Geol. Soc. Jap.: 116, Kochi.Suzuki, H., Wegerer, E. & Gawlick, H.-J. (2001): Zbl. Geol.

Palaont. Teil I 2000: 167–184, Stuttgart. Tollmann, A.(1985): Geologie von Österreich, Band 2. 1–710, (Deu-ticke) Wien.

Geo.Alp, Vol. 4, 200790


CCAALLLLOOVVIIAANN TTOO OOXXFFOORRDDIIAANN RRAADDIIOOLLAARRIIAANNSS FFRROOMM AA ““SSLLOOVVEENNIIAANN//BBOOSSNNIIAANN TTRROOUUGGHH””--TTYYPPEESSUUCCCCEESSSSIIOONN AALLOONNGG TTHHEE PPEERRIIAADDRRIIAATTIICC LLIINNEEAAMMEENNTT ((KKAARRAAVVAANNKK MMOOUUNNTTAAIINNSS,, AAUUSSTTRRIIAA))

Hisashi Suzuki, Sigrid Missoni, and Hans-Jürgen Gawlick

University of Leoben, Department for Applied Geosciences and Geophysics, Peter-Tunner-Str. 5, A-8700 Leoben

The Karavank Mountains (Austria) display a suite of in-dividual stratigraphic successions of partly differentpalaeogeographic derivations, today forming imbricatesof variable size. A geological complex segment with a“Slovenian/Bosnian Trough”-type succession is locatedbetween the Maria-Elend Sattel and the Schwalbenwand.Above grey thin bedded turbiditic to bioturbatic Sevatianto Rhaetian radiolarian-rich limestones with mass-flowand sliding complex horizons (= Frauenkogel Formation;KRYSTYN et al. 1994) and the Rhaetian to Early Jurassic greyargillo-calcareous bioturbate to turbiditic wackestones (=Hahnkogel Formation; KRYSTYN et al. 1994) follow grey,thin bedded, turbiditic, radiolarian-rich wackestones ofMiddle/Late Jurassic age (= Kahlkogel Formation, as a partof the Ruhpolding Radiolarite Group).

In these radiolarian-rich wackestones, from theKahlkogel Formation with mostly poor preserved radiolar-ians, the occurrence of Middle/Late Jurassic radiolarians isreported for the first time. From these dark radiolarianwackestones, following radiolarians can be identified:Bernoullius cristatus BAUMGARTNER 1984, Archaeodicty-omitra sp., Hsuum cf. brevicostatum (OZVOLDOVA 1975),Parvicingula cf. dhimenaensis BAUMGARTNER 1984, Dicty-omitrella sp., Triversus cf. hungaricus (KOZUR 1985),Podobursa cf. nodosa (CHIARI, MARCUCCI & PRELA 2002),Unuma gorda HULL 1997 [= Unuma sp. A sensu BAUMGART-NER et al. 1995], Quarticella cf. ovalis TAKEMURA 1986,Williriedellum dierschei SUZUKI & GAWLICK in GAWLICK et al.2004, Williriedellum glomerulus (CHIARI, MARCUCCI & PRELA

2002), Zhamoidellum cf. ovum DUMITRICA 1970, Stylocapsaoblongula KOCHER 1981, Gongylothorax aff. favosusDUMITRICA 1970, Gongylothorax sp. C sensu SUZUKI &GAWLICK 2003, Theocapsomma medvednicensis GORICAN inHALAMIC et al. 1999, Tricolocapsa conexa MATSUOKA 1983,Tricolocapsa undulata (HEITZER 1930) [= Sethocapsa funa-toensis AITA 1987], Praewilliriedellum cf. spinosum KOZUR

1984, Stichocapsa convexa YAO 1979, Eucyrtidiellum cf.unumaense (YAO 1979), Eucyrtidiellum unumaense ssp.(YAO 1979), Eucyrtidiellum cf. ptyctum (RIEDEL & SANFILIPPO

1974). BECCARO (2004) reported the occurrence of Eucyrtidiel-

lum unumaense from an Ammonitico Rosso section ofnorthwestern Sicily dated by ammonites as Middle Oxfor-

dian to Late Kimmeridgian. The last appearance horizon ofE. unumaense is revised at least to Middle Oxfordian(upper limit of the Williriedellum dierschei subzone of theZhamoidellum ovum zone after SUZUKI & GAWLICK 2003).The radiolaria Zhamoidellum ovum (Callovian to EarlyTithonian, respectively U.A. Zones 7-11) is the indexspecies for the Zhamoidellum ovum zone (Callovian toOxfordian). Gongylothorax aff. favosus is defined for theU.A. Zones 7-8 (Late Bathonian to Early Oxfordian - BAUM-GARTNER et al. 1995), respectively for the Protunumalanosus subzone (Callovian) to Williriedellum dierscheisubzone (Early to Middle Oxfordian) of the Zhamoidellumovum zone. Thus, recent systematic studies on G. aff.favosus obtain in this sample an atypically species, with aninflated, less depressed cephalis in the thoracic cavity. Theradiolaria Podobursa nodosa indicate only a Middle toearly Late Jurassic age, its stratigraphic range should befurther studied. Triversus hungaricus, originally describedin the Unuma echinatus zone of southwest Japan andHungary are determined to be Bajocian in age (YAO &BAUMGARTNER 1995). SUZUKI & GAWLICK (2003) reported thisspecies from the Zhamoidellum ovum zone of the North-ern Calcareous Alps. Praewilliriedellum spinosum wasoriginally also described from the Unuma echinatus zone(Bajocian) of the southern Bükk Mountains (KOZUR 1984),and is also reported from the Williriedellum dierschei sub-zone. Consequently, radiolarians from these radiolarian-rich wackestones of this segment south of Maria Elend in-dicate a Callovian to Early/Middle Oxfordian age.

Hence, the sedimentation until the Middle/Late Juras-sic in this belt is in line with the model of out-of-sequencethrusting in the Juvavicum since the Early/Middle Jurassicboundary, and continuous sedimentation on the back-limbs of the nappes. Lateral motions since the Turonianformed a mega-imbricate zone between the Dinaridesand the Eastern Alps contemporaneous with the move-ment of the Drau Range and the Transdanubian Range to-wards the east, to their present position.

With financial support of the FFG-Project810082/9814 in cooperation with the STW Klagenfurt AG– Geschäftsfeld Wasser.

Geo.Alp, Vol. 4, 2007 91


SSEEDDIIMMEENNTTOOLLOOGGIISSCCHHEE BBEELLEEGGEE IINNVVEERRSSEERR LLAAGGEERRUUNNGGVVOONN GGEESSTTEEIINNSSEEIINNHHEEIITTEENN IINN DDEENN NNÖÖRRDDLLIICCHHEENN KKAALLKKAALLPPEENN

Eva Wegerer1 und Godfrid Wessely2

1 Montanuniversität Leoben, Department Angewandte Geowissenschaften und Geophysik, Lehrstuhl für Prospektion undAngewandte Sedimentologie, Peter-Tunner-Straße 5, A-8700 Leoben

2 Godfrid Wessely, Siebenbrunnengasse 29, A-1050 Wien

Die Feststellung inverser Lagerung beruht auf der Be-achtung des Geopetalgefüges, das sich sowohl aus Karbo-naten, als auch siliziklastischen Gesteinen, ablesen lässt.Meist ermöglicht die Gesteinsabfolge zusammen mitihrem Einfallen eindeutige Aussagen, es gibt jedoch vieleFälle, wo eine Geopetalanalyse notwendig ist. Beispiels-weise wenn Internzerschiebung oder andere Störungenden Verband lückenhaft gemacht oder zerrissen haben,wenn sich Fensterinhalte und deren Rahmen in ihren Ab-grenzungen nicht klar definieren lassen, wenn Aufschlus-sarmut vorliegt, wenn, wie etwa bei Bohrungen, Lateralin-formation nicht in ausreichendem Maße verfügbar ist.

Bei Karbonaten können sowohl sedimentations- alsauch diagenesebedingte Kennzeichen beobachtet wer-den: Kleinerosionen, wie Kappungen von Lagen, Auskol-kungen etc., Einbettungsarten von Fossilien, Füllungsab-folgen in Hohlräumen (Kalzitrasen an den Oberseiten),Entgasungsblasen. In siliziklastischen Gesteinen sind esebenfalls erosionsbedingte Sedimentmarken, vor allem anUnterkanten von Sandsteinbänken als Ausgüsse von Ein-tiefungen im unterlagernden Feinsediment, aber auch In-ternstrukturen von Rippeln. Fehldeutungen können ent-stehen, wenn beispielsweise Drucksuturen sedimentäreAnlage vortäuschen oder wenn die Unterkante einer Rip-pelstruktur mit einer Kappung verwechselt wird.

Aus den Nördlichen Kalkalpen werden Beispiele unteranderem aus der „Sattelbachserie“ an der Stirne der GöllerDecke des Wienerwaldes, aus dem großdimensionalen In-versabschnitt der Sulzbachdecke im Annaberger Fensterund westlich davon, sowie aus einer überschlagenen Flan-ke der Gosaumulde südlich Hainfeld angeführt. Durch diedetaillierte Untersuchung der Gesteine, die bisher als un-mittelbarer Rahmen des „Schwechatfensters“ galten,nämlich Lunzer Schichten, Reiflinger Kalk und Steinalm-kalk, stellte sich heraus, dass diese ebenso invers liegen, wieder bisherige „Fensterinhalt“, der aus einer bekannt inver-sen Schichtfolge aus Jura und Obertriaskarbonaten be-steht. Dadurch verbleibt nur ein sehr lückenhafter Rahmenaus einer nächst höheren Schuppe, der Lindkogelschuppe.

Die Untersuchungsergebnisse in der inversen Sulz -bachdecke im Annaberger Fenster und im Gebiet der Gfäl-ler Alm sowie das Ergebnis der Bohrung Mitterbach U1, inder ebenfalls die inverse Sulzbachdecke angetroffenwurde, gehen konform mit der Kenntnis um eine 12 kmbetragende Erstreckung der inversen Serie dieserDeckeneinheit. Dies kann nur durch Abrollbewegungeines liegenden Mulden- Faltensystems erfolgt sein. In-verse Abfolgen sind vor allem in Stirnrollen tektonischerÜberschiebungseinheiten sowie bei Einengungen vonMuldenzonen, wie Gosaumulden anzutreffen.

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