SLOVAK ACADEMY OF SCIENCES

INSTITUTE OF GEOGRAPHY

AD-A254 927

ABSTRACTSOF PAPERS

INTERNATIONAL SYMPOSIUM

DTICELECTE f,Mkt 17 1992

A UThis document has been approved i

for public release and sale; itsdistibution is unlimited.

TIME, FREQUENCY AND DATINGIN GEOMORPHOLOGY

C ZECHO-SLOVAKIATATRANSKA LOMNICA - STARA LESNA

June 16-21, 1992

Bratislava 1992 Wi

International Geographical UnionCommission on measurementTheory and Application

in Geomorphology

Czecho-Slovak Committee Institute of Geographyfor the International of the Slovak AcademyGeographical union of Sciences

1E3 S rIR- AC OrE D F I A. -r> E T.SE

Editor: Milo& Stankoviansky

INTERNATIONAL SYMPOSIUMTINE, FREQUENCY AND DATING IN GEOMORPHOLOGY

(STIFDIG)

TATRANSKA LOMNICA-STARA LESNA, CZECHO-SLOVAKIAJUNE 16-21, 1992

FREQUENCY,TIME

Bratislava, 1992

92 812 019

Institute of Geography of the Slovak Academy of sciences,

Bratislava 1992

International Symposium on Time, Frequency and Dating inGeomorphology, TatranskA Lomnica - Star& LesnA, June 16-21, 1992

HONORARY COMMITTEE

Prof. Dr. V. Gardavsky, Chairman, Czecho-loval. Committee for theIGUProf. Dr. V. Kral, Charles University, PragueProf. Ing. S. Markug, President, First Division of Sciences(Abiotic Nature), SASProf. Dr. L. Kresak, Chairman, Scientific Board, Collegium ofEarth and Space Sciences, SASDoc. Dr. A. Bezak, Director, IG, SASDoc. Dr. P. Korec, Chairman, Geographical Section, Faculty ofSciences, Comenius University, Bratislava

INTERNATIONAL ADVISORY BOARD

Prof. Dr. A. P. Schick, Hebrew University, Jerusalem, Israel(COMTAG Chairman)Prof. Dr. F. Ahnert, Technical University, Aachen, GermanyProf. Dr. T. Czudek, IG, CSAS, Brno, CSFRProf. Dr. J. Demek, University of Olomouc, CSFRProf. Dr. T. Dunne, University of Washington, Seattle, USAProf. Dr. A. Rapp, University of Lund, SwedenDr. A. Werritty, University of St. Andrews, Scotland, UK

LOCAL ORGANIZING COMMITTEE (Institute of Geography, SlovakAcademy of Sciences)Dr. M. Stankoviansky (Chairman), Dr. J. Hanugin, Dr. J. Jakal,Dr. J. Lacika, Dr. M. Lehotsky, Dr. t. Solin, Dr. J. Urbdnek,t. Kohan

C10

ACKNOWLEDGEMENTS

Institute of Geography of the Slovak Academy of Sciences isgrateful for financial support provided by the European ResearchOffice of the U.S.Army (London). es

3

DTIC QUALITY INSPECTED 2

CONTENTS

AMIT, R.: Contribution to the stage and rate of biogeniccalcrete formation using 14C measurements by liguidscintillation counting method ................................ 7

BALOGH, K., ELE6KO, M., KONE6Nt, V.,LACIKA, J., ORLICKI, 0.,PRISTAA, a., VASS, D.: Correlation of the results of dating

examplified by the Cerov& basaltic formation ................. 8

BAUNGART-KOTARBA, N.: Effect of time on the evolution of twogeomorphic systems: proximal braided river in the PolishCarpathian and torrential fan in the Tryn Basin ofBulgaria ..................................................... 9

BIZUBOVA, x., mINAR, J.: Some new aspects of denudationchronology of the West Carpathians .......................... 10

BRUCKNER, H., LAOUINA, A., HALFAR, R., HAMBACH, U.: Datingmarine and eolian sequences in the Rabat region, Morocco .... 11

CHUECA, J., JULIAN, A.: Lichenometry: some difficulties inthe establishment of reliable lichen growth curwes .......... 12

CLARK, G. M.: Application opportunities for cosmogenicdating methods in the study of diamicton deposits,Central Appalachian Mountains, U.S.A ........................ 13

CZUDEK, T.: Brunhes - Matuyama boundary and geomorphologicaldevelopment of the Middle - Moravian Carpathians ............ 14

CIN!qURA, J.: Development of the Slovak Western Carpathianrelief in space and time .................................... 15

6IN6URA, J., KOHLER, E.: Dating of the longest paleokarstperiod in the Western Carpathians ........................... 16

FROEHLICH, W., WALLING, D. E.: Some comments on thepotential for using caesium radionuclides to investigateoverbank sedimentation in Carpathian rivers ................. 17

HALOUZKA, R.: Glacial stratigraphy and dating of theQuaternary accumulation forms and deposits on theforeland of the Tatra Mts ................................... 18

HALOUZKA, R., dIXON, L.: Dating report about Quaternarylatest volcanic activity in Czecho-Slovakia (basalts nearNova Baha - Brehy) .......................................... 19

HARIIAR, J., KRIPPEL, E.: Morphogenesis of gravitation slopedeformations in the Vihorlat Mts (based on palynologicaldating) ..................................................... 20

4

HARRISON, J. B. J., YAIR, A.: The significance of interdunaldeposits in the Nizzana Sands, Southern Negev, Israel ....... 21

HEINE, K.: The effects of time on the evolution of

geomorphological cycles in the Namib Desert, Namibia ........ 22

INBAR, M.: Evolution and recovery time of volcanic landforms... 23

JHA, V.: Gully erosion and its role in environmentaldegradation (a case study) .................................. 24

KASHIWAYA,K., OKIMURA, T.: Frequency in erosional processesand environmental information ............................... 25

KIRCHNER, K., NOVAdEK, V.: Development of the Morava Riverbed near Strdinice (south Moravia) .......................... 26

KOTARBA, A.: Late-Holocene slope denudation in the PolishTatra Mountains seen in the light of lacustrine studies .... 27

LEHOTS", M.: Young landform dating by using of caesium-137 .... 28

LI, Y. Q., JU, X. M.: Time, magnitude and frequency incontemporary geomorphology (some theoretical issues) ........ 29

LI, Y. Q., JU, X. M.: Time in the evolution of semi - aridcatchments (the loess plateau model) ........................ 30

LIKHACHEVA, E. A.: Stability - the function of time ............ 31

LIN, J. CH.: First - order 14C dating of the Coastal Range,Eastern Taiwan .............................................. 32

LO2EK, V.: Geomorphic processes in the light of Quaternarybiostratigraphy ............................................. 33

MAC, I., IRIMUS, I.: Volcanites - sculptural landformsinterferences in Romanian volcanic mountains (premisesfor datings in geomorphology) ............................... 34

MIDRIAK, R.: Rate and dynamics of contemporaneous erosiveprocesses induced by the surface runoff in highmountains of the West Carpathians ........................... 35

ONDRWIK, R.: Main stages of the West Carpathiansgeomorphological evolution and their dating ................. 36

PERA, J. L., CHUECA, J., JULIAN, A.: Archaeological dating,geomorphological reconstructions and palaeoclimaticcorrelations in northern Spain .............................. 37

5

RADOANE, M., ICHIM, I.: Contemporary trends of the riverchannel beds (case study from Romania) ...................... 38

RADTKE, U.: Electron spin resonance (ESR) dating ingeomorphology ............................................... 39

RAPP, A.: Time and frequency of slope erosion events innorthern mountains .......................................... 40

SCHICK, A. P., GREENBAUM, N.: Magnitude, frequency anddating of floods - some questions and initial answersfrom a study in the Negev Desert, Israel .................... 41

de SERPA MARQUES, B., de SOUSA PEDROSA, A.: Man's action andslope erosion. The catastrophe in Arosa (1981) .............. 42

STANKOVIANSKY, M., LEHOTSKI, M.: Utilization of thepedo-geomorphic approach in a study of valley networkchanges (on the example of the Gidra catchment in theDanube Lowland) ............................................. 43

STARKEL, L.: Flood frequency during the Holocene in theupper Vistula basin (based on sediments, forms andabsolute datings) ........................................... 44

STRUNK, H.: Dating and frequency analysis of geomorhologicalprocesses using dendrogeomorphological methods .............. 45

SURDEANU, V., ZEMIANSCHI, S.: Cyclicity and frequency oflandslides in Romania ....................................... 46

TIMOFEEV, D. A.: A new approach in understanding ofgeomorphological time ....................................... 47

TIMOFEEV, D. A., UFINTSEV, G. F.: Age and time of relief:results of the Irkutsk conference 1991 ...................... 48

TRIMBLE, S. W., COOKE, R. U.: Historical approaches togeomorphological dating ..................................... 49

UFIMTSEV, G. F.: Geological and own time of relief ............. 50

ZOLLER, L.: Luminiscence dating of sediments - limitationsand perspectives ............................................ 51

6

CONTRIBVTION TO THE STAGE AND RATE OF BIOGENIC CALCRETE FORMATION

USING 'C MEASUREMENTS BY LIQUID SCINTILLATION COUNTING METHOD

AMIT, R.

Calcrete bearing soils and paleosols are being used as atool for paleoenvironmental and paleoclimatic reconstruction.They are found to be very important in subdividing andcorrelating Quaternary deposits. The accuracy ofpaleoenvironmental reconstructions and correlations requires anunderstanding of the'rates and processes of formation of calcichorizons. Two types of calcr'te formation have been identified,biogenic and physico-chemical. Most studies of rates andformation of calcrete horizons focus on the physico-chemicaltype. Rates and processes of biogenic calcrete formation arepoorly understood.

Several biogenic calcrete horizons, developed on aMiocene limestone parent material, under Mediterranean climaticconditions, in Tarragona, Spain, were dated. The analyses alsoincluded micromorphology and stable isotopes. Age dating was doneby the liquid scintillation counting method for carbon.

Results indicate that it is possible to separate two majorstages in the formation of the biogenic calcrete horizons. Thefirst stage is a passive accumulation of calcium carbonate inspecific sites, for example in the roots and root hairs cellwalls and in the mucilage which the roots secrete. The passiveaccumulation is accompanied by an active deposition of calciumcarbonate crystals by fungi and bacteria inside and outside theirfilaments. This stage can last more than 7 800 years withoutindurating the calcrete horizon. The second stage ischaracterized by physico-chemical precipitation of calciumcarbonate in micropores while the fungi and bacteria continue tocontribute to the final cementation of the calcrete horizon. Atthis stage the passive accretion of calcium in the organiccompounds continue but it is not the main mechanism of calciumcarbonate accumulation. The overall induration of a biogeniccalcrete horizon can take between 10 000 to 16 000 years and evenmore.

With time the accumulation of calcium carbonate by thebiogenic activity in the rhizosphere causes a decrease in thepermeability and change in moisture conditions of the soilprofile. The modified micro-environmental conditions become lesssuitable for the rhizosphere activity and a process ofphysico-chemical deposition of calcium carbonate becomesdominant. The physical cementation process cause completeplugging of the calcic horizon and converts it to a hardpan. Thissecond stage predominates by a destructing of the less resistancebiogenic features which exist in the calcrete horizon, forexample, plant tissues or the needle fibre calcite. The moreresistant biogenic products, like the mucilage, remain, even in amature and very indurated horizon. The occurrence of mucilage maybe used in distinguishing biogenic calcrete horizons of stage twofrom purely physico-chemical calcrete horizons.

i.stitute of Earth Sciences, The Hebrew University of Jerusalem,Israel

7

CORRELATION OF THE RESULTS OF DATING EXAMPLIFIED BY THE CEROVABASALTIC FORMATION

BALOGH, K.") ELEd (2) KONE.N., V (2),Lt{KA. >j3),ORLCK, . ),PRISTASJ., VASS D.

In the article we attempt to objectivize the dating ofgeological and geomorphological phenomena and forms by means ofmutual confrontations of various methods realized on identicalunit and identical area. The Cerova Basaltic Formation is verysuitable for this aim, because it underwent numerous measurementsand it was geomorphologically researched in details.

The investigated formation participates in thevolcanosedimentary geological structure of the Cerova VrchovinaMts in southern Slovakia. It is of Plio-Pleistocene age. Itconsists of basalts, basanitoides and their volcanoclasticrocks. They build only a smaller part of the mountains, but theyare of a great importance for the forming of local positivemorphostructure. The basaltic volcanism accompanied and earlierperiod of the rise of dome-horst morphostructure. Its productswere incorporated into the geological structure monotonous untilthat time and this fact was a condition for and inversion oflandforms development as to the initial prevolcanic shape. Theuplifting of the morphostructure initiated an exogenedestruction of original "-,canic landforms mainly by periglacialprocesses in the cold periods of the Pleistocene.

The Cerova Basaltic Formation underwent several datingmeasurements. By mutual correlations of the results of theindividual measurements confronted with the results of thegeomorphological research we achieved in most cases a statementthat they coincide within an admissible temporal span. Wedistinguished 6 basic periods of the volcanic activity within 0,4to 6,1 m. a. interval by means of K/Ar method andpaleomagnetically, biostratigraphically and geomorphologically.Only the results of measurement obtained by means of the fissiontrack method does not correspond to the other results of thedating. According to them the age of the basalts in the CerovaVrchovina Mts may be interpreted for more than 7,5 m. a.

M1 )Institute of Nuclear Research, Hungarian Academy of Sciences,Debrecen, Hungary

(2 )Dionyz gtur Institute of Geology, Bratislava, CSFR(3 )Institute of Geography, Slovak Academy of Sciences,

Bratislava, CSFR(4 )Institute of Geophysics, Slovak Academy of Sciences,

Bratislava CSFR

EFFECT OF TIME ON THE EVOLUTION OF TWO GEOMORPHIC SYSTEMS:PROXIMAL BRAIDED RIVER IN THE POLISH CARPATHIANS AND TORRENTIAL

FAN IN THE TRYN BASIN OF BULGARIA

BAUMGART-KOTARBA, M.

Time's effects in geomorphology are controlled by climaticand neotectonic factors and also by lithology and time ofrecurrence. In the case of the fluvial environment the role ofdischarge as function of catchment size pulls out ahead. The aimof the paper is to illustrate the rate of geomorphologicalactivity in two different fluvial environments.

The example of braided proximal e~vironment of the BialkaRiver (A=232 km2 , min.discharge 5 m /sec, effective floods200-400 m /sec) with source area within the northern slope of theTatra Mts illustrate postglacially reworked fluvioglacialdeposits. The large floods with recurrence of 6-7 years produce anew flood channels with alternate scouring and accumulation on100-200 m long reaches. During 2-3 day flood related to dailyprecipitation of 100 mm scouring or accumulation of the order of1-1,5 m in the channel was established. During 50-100 yearsbraid-plain is totally reworked (width of 100-500 m). During 1000years the 1 m deepening of whole alluvial plain against the youngterrace has taken place. The rate of deepening 1 mm/year could becomparable with the rate of Holocene dissection of Late Glacialterrace of 8-10 m high.

The exarple of torrential fan (radius of 1,5 km) from theTryn Basin in the marginal zone of the Rui Mts demonstrateHolocene activity. This fan is modelled by episodic stream. Theintensive rainfall 70-100 mm per day were recorded only a fewtimes during this century. Structure of fan up to 3,5 m istripartite. The lower part (1,2 m) consits of loam with gravel.The middle part, 0,8 m thick represents period of more organicdeposition. A? of organic layer in its central part wasevidenced by C data (6000-4000 BP for residuum and for huminacid). This horizon was fossilized by 1,5 m clayey-silt layer. Inthe loyIr part of overbank organic muds of the Erma River theolder C data (10 000 and 6 000 BP) were established. This 1,1m thick muds are covered by 0,7 m of laminated silt. The rate ofmid-fan accumulation for the last 4 000 years is 0,4 mm/year. Therate of earlier more organic accumulation is 0,13-0,4 mm/year. Ifthe lower part with coarse material represents more activepre-Holocene formation the organic part could be related toBureal and Atlanticum with rate 0,13 mm/year.

Institute of Geography and Spatial Organization, Polish Academy

of Sciences, Krakow, Poland

9

SOME NEW ASPECTS OF DENUDATION CHRONOLOGY OF THE WEST

CARPATHIANS

BIZUBOVA, M., MINAR, J.

In the contribution, the Neogene denudation chronology ofWest Carpathians traditionally used in Slovakia (Mazur 1963) iscritically revalued from the point of view of latest geologicalchronostratigraphy of central Paratethys. The mentionedchronometric scale approaches some of the Neogene epochs and agesin a new way and it changes the time determination of individualNeogene orogenic phases. The insufficient sizing up thetransformation relation between earlier and latestchronostratigraphy on the one hand, and the denudation chronologyon the other hand, causes the heterogeneous approache to the WestCarpathians genetic forms dating of Slovak geomorphologists, too.This dissonances are emphasized by schematicity and staticapproach of traditional denudation chronology of West Carpathiansthat did not take sufficiently into account spatialdifferentiation of tectonic movements during orogenic phases.

The suggestion of modified West Carpathians denudationchronology, that considered this new facts, is presented in thepaper. It modifies individual West Carpathians geomorphologiccycles' dating and defines the cycle, up to this time notconsidered, that is showed up by the planation surface named inadvance as "underintramontane level". Its existence is documentedby several examples.

At the end of the paper, possible ways of the dating ofbeginning and finishing West Carpathians planation surfacesforming are showed (by study of weathering crust, by the age ofgeological bearer of planation surface, by loaded and subsequentgeomorphic forms, and the like). There are showed the problemsand possibilities of identification of multigenetic planationsurfaces that resulted mainly from considerable differentialtectonic movements.

The paper, as a whole, is formulated problemly. It outlinesseveral relevant questions and shows some way of solution.

Comenius University, Bratislava, CSFR

10

DATING MARINE AND EOLIAN SEQUENCES IN THE RABAT REGION, MOROCCO

BRUCKNER, H."I ), LAOUINA, A.

(2 ) , HALFAR, R. (3 ) , HAMBACH, U.(4 )

The Atlantic coast of Morocco displays one of the mostcomplete sequences for the marine Pliocene and Quaternary ofAfrica. Due to the interference of the continuous uplift of theMoroccan meseta with the sea-level fluctuations since thePliocene, a series of beach-ridge complexes has been deposited.Each one consists of littoral gravels and sands plus thefossilized former dunes. These sequences exist both laterally andvertically. Paleosols and erosional disconformities separate thedifferent sedimentary cycles.

The cycles were stratigraphically analyzed by paleosol andmineralogical studies. Different dating techniques (C-14,Th-230/U-234, thermoluminescence /TL/, electron spin resonance/ESR/, paleomagnetics) were used to establisha chronostratigraphy.

TL dating of dunes and eolianites rendered reliable resultsup to c. 100,n00 years B.P. Supported by the investigation ofintercalated paleosols and paleosol sediments, a differentiatedchronology of the geomorphodynamic events during the last glacialepoch is established.

Deposits of the last interglacial are well exposed atvarious sites. However, a discrimination with the absolute datingtechniques is not possible due to their gross resolution. It isfrom geomorphological aspects that the last interglacial trans-and regressions can be deciphered.

Since the majority of the beach ridges is older than thedating range of the Th/U dating technique (up to c. 350 ka) andsince recrystallization made an ESR dating practicallyimpossible, the focus was on the paleomagnetic investigation ofthe older beach ridges. The paper presents the paleomagneticstratigraphy of the region which has for the first time beenstudied under this aspect.

(1 )University of Marburg, FRG(2 )University of Rabat, Morocco(3 )University of Dusseldorf, FRG(4 )University of Munster, FRG

11

LICHENOMETRY: SOME DIFFICULTIES IN THE ESTABLISHMENT OF RELIABLELICHEN GROWTH CURVES

CHUECA, J., JULIAN, A.

In this work, the results obtained through the elaborationof a Rhizocarpon geographicum (s.l.) growth curve carried out fora sector of the southern Central Pyrenees are shown. The studyarea comprises the upper part of the Esera river basin, in theBenasque valley, and is ubicated in the axial section of thismountainous range, characterized by the presence of crystallinelithologies (granites, granodiorites) and recently glaciatedlandforms. The choice of this zone was motivated by the abundanceof historical ruins (churches, hermitages, graveyards, etc.) -well documented and dating from the end of the XVIII century upto now - built in those materials and showing a plentiful lichencovering.

In this process of constructing the lichen growth curve weattempt to accomplish a methodological approximation, trying tocompare the validity and degree of similarity of differenttechniques usually mentioned: 1) measurements of the largestdiameters; 2) percentage cover measurements, and 3) determinationof size frequency distributions. All of them were used in thesame sample points and allowed us to build up three independentgrowth curves. The statistical calculation of the similaritylevel existent among them have let us infer some conclusions thatafirm the relative reliability of chronologies obtained throughthe utilization of a single method. The comparison with thepresent-day growth-rates of several samples of R. geographicumwith different ages measured by photogrametrical techniquesduring the last two years in the same study area, has indicatedthe existence of a notable degree of general adjustment for onlythe last two options, while the first approximation seems to beunacceptable.

Zaragoza University, Spain

12

APPLICATION OPPORTUNITIES FOR COSMOGENIC DATING METHODS IN THE

STUDY OF DIAMICTON DEPOSITS, CENTRAL APPALACHIAN MOUNTAINS,U.S.A.

CLARK, G. M.

Large areas in the Piedmont, Blue Ridge, Ridge and Valley,and Appalachian Plateaus physiographic provinces of theAppalachian Highlands major geomorphic division are blanketed bydiamicton deposits of unknown ages. These sediments includecolluvium, alluvium on high terrace levels, and - in the vicinityof the glacial borders - glacial sediments of pre-Wisconsinan(pre-Wurm) ages. Many of these sediments lack suitable materialsthat could be dated by established numerical age datingtechniques.

Cosmogenically-produced isotopes of 10 Be, 14C, 26AI and 36 C1can be measured accurately with small sample sizes by AcceleratorMass Spectrometry (AMS). The analytical results can provideexposure ages and estimates of erosion rates over suitableintervals of geomorphic time, if suitable sample localities canbe found. Field research results indicate that the tops of torscomposed of orthoquartzite and metaquartzite bedrock offer thebest opportunity for sample points. Large tors project severalmeters above the surrounding forest floor and offer protectionfrom effects of spallogenic (thick rind type) weathering relatedto fire events. The presence of Opferkessel on exposed tor topsis strong evidence that these surfaces have been exposed forcosmogenic bombardment for at least the time duration requiredfor these solutional features to form in high-purity quartzitebedrock. Tor exposure and weathering history can than be relatedto the surrounding regolith through both soil-stratigraphic andgeophysical research methods.

These new data will be used: to test multiple workinghypotheses on landform and material origin and evolution, and toconstruct a numerically-dated Quaternary terrestrial history.This research will advance knowledge by providing quantitativedata on rates of erosion and landform evolution, and on theinfluence of climatic change on landscape development.Appalachian Laurentide terrestrial glacial border andpalaeoperiglacial records will then be correlated with the NorthAtlantic marine record. This combined record will then be relatedto research results elsewhere, and used in evaluation ofpole-to-pole global change models.

University of Tennessee, Knoxville, USA

13

BRUNHES-MATUYAMA BOUNDARY AND GEOMORPHOLOGICAL DEVELOPMENT OF

THE MIDDLE-MORAVIAN CARPATHIANS

CZUDEK, T.

The Middle-Moravian Carpathians are formed of hilly andupland relief on strongly folded Paleogene claystones,sandstones, sands and conglomerates of the flysh zone and Neogenedeposits (clays and sands). The highest unit of theMiddle-Moravian Carpathians is represented by the Chkiby Upland(max. absolute height 587 m). It is a strongly dissected regionwith narrow, often rocky watershed ridges and isolated elevationsas well as deeply incised valleys (as many as 120 m) with steepgradient of slopes. The major water courses follow the generalinclination of the territory flowing from the Chfiby Uplandsoutheastwards. In the lower land area on the margin of theKyjovska Pahorkatina Hilly Land and especially in theDolnomoravsky Oval Graben, they form extensive, even 30 m thickalluvial fans.

In one of the alluvial cones, i.e. southeast of the villageBor~ice near Buchlovice, the Brunhes-Matuyama bondary wasdetermined in a depth of about 9 m (Czudek, Havlidek, Kovanda1985). The material of the alluvial cone of the Dlouha tkeka Brookabove and below the boundary differs considerably. Thesedimentation below the Brunhes/Matuyama boundary was fast,chaotic. The material is rather coarse-grained and badly sortedwith less rounded pebbles. The sedimentation above the B-Mboundary appears to be calmer. The material is visibly moresorted, the gravel becomes finer and more rounded. No successiverefinement of the gravel upwards is to be observed in thesequence of the Quaternary strata. The Brunhes-Matuyama boundaryrepresents here a quite expressive lithological(sedimentological) limit. Accordingly it can be concluded, thatthe intensity of tectonic uplifts in the Chfiby Upland andprobably in the entire Middle-Moravian Carpathians was heigher inEarly Pleistocene than in the Middle and evidently even UpperPleistocene.

Institute of Geography, Czechoslovak Academy of Sciences, Brno,

CSFR

14

DEVELOPMENT OF THE SLOVAK WESTERN CARPATHIAN RELIEF IN SPACE AND

TIME

dINdURA, J.

The Western Carpathians formed as a result of a collision ofthe NW projection of the Apulian microcontinent with the marginof the European platform. This collision took place duringseveral stages (megacycles) which can be distinguished in thesedimentary record as well as in the erosional history.

Traces after the oldest reliefs of the Alpine period are notpresent in the present-day relief. However, they can bereconstructed from the sedimentary record. Lower Triassicquartzites reflect one of the oldest Carpathian reliefs. They areinterpreted as sediments of ephemeral streams deposited in aPiedmont lowland in semiarid climate. Gutenstein limestones anddolomites of Middle Triassic age represent sediments of sebkhaenvironemnt. Pseudomorphs after anhydrite and gypsum crystalsindicate aridity of the environment. On the boundaryTriassic/Jurassic there are known the up to now oldest karstphenomena of the Alpine period. Breccia limestones of Lower Liasage penetrate deep into the underlying limestones in the form offilling of widened fissures or surfacial depressions. In theJurassic period there are not known any terrestrial sediments ortraces of subaeric relief.

As a result of the collision development, an importantcontinental period started during the Cretaceous in the Centraland Inner Western Carpathians. Subaeric conditions progressedgradually from the south to the north. A wide scale of typicalkarst forms and sediments originated in monsoon or subequatorialclimate conditions on carbonate rocks; among them also karstbauxites. This important karst period started generally duringthe Middle Cretaceous.

The progressing Paleogene sea interrupted the period ofsubaeric development. The mainland was gradually flooded andPaleogene sediments buried the pre-transgressive relief.

The collision development during the Neogene caused not onlyhorizontal and vertical movements, but also rotation of blocks.The buried pre-transgresive relief was gradually exhumed andpartially eroded. The maxima of sedimentation rate in molassebasins migrated not only in time, but also in space from W to E,similarly as volcanic activity. Therefore the formation ofextensive synchronal levelled surface in source areas of the'frontal deep, intramontane basins as well as of the backdeep(i.e. the outer, inner and back molasse) appears to be incontradiction to the conception of dynamic evolution in theWestern Carpathians.

Geological Institute, Slovak Academy of Sciences, Bratislava,CSFR

15

DATING OF THE LONGEST PALEOKARST PERIOD IN THE WESTERNCARPATHIANS

dINdURA, J., KOHLER, E.

The considerable areal extent and great thicknesses ofcarbonate complexes - especially limestones and dolomites ofMiddle and Upper Triassic age - in the Inner and Central WesternCarpathians led in the periods of subaeric development to theformation of paleokarst. In accordance with the model ofcollision development of the Western Carpathians during theAlpine period it can be stated that the most important paleokarstdevelopment periods were initialized by the Early Kimmerian,Middle Cretaceos (Austrian) and Savic-Styrian phases.

In spite of the fact that Cretaceous transgression ment inglobal scale the largest inundations, the Middle Cretaceous(Austrian) collision caused, especially in the Central Carpathianspace, a diametrically opposed development. The duration of thelongest paleokarst period in the Western Carpathians can bechronostratigraphically defined by its lower and upper boundary.The onset of this paleokarst period was different in the WesternCarpathians. The southernmost units emerged already at the end ofUpper Jurassic. The youngest sea sediments of Hronicum (southernparts) are of Barremian age, in Fatricum (more central parts)they are Late Albian to Cenomanian, the sediments of thelowermost Turonian are locally known in Tatricum (northernmostzones).

Among products of the longest paleokarst periods are typicalkarst bauxites forming the filling of karst cavities, ferrousweathering crusts, red clays, colapse breccias with speleothems,freshwater limestones or polymict conglomerates. Surfacial formsof this period are large depressions of polje charakter, hums orextensive paleokarst plateaus.

The longest paleokarst period in the Western Carpathians wason a great part of the territory ended by transgression ofPaleogene sea which flooded the northern part of the Male KarpatyMts, Myjavska Pahorkatina, Vah valley, Orava and Pieniny alreadyin the Paleocene. The most marked progress of the sea can beobserved in the Middle and Upper Eocene, when progressing from NWto SE, the sea flooded a considerable part of the paleokarstrelief. The progress of the sea continued until the end of theEocene, the youngest basal beds of the uppermost Eocene are knownfrom the region ftrba-Ludivna. In the Middle and Upper Eocenea shallow epicontinental sea reached from the south to theWestern Carpathians, to the region of Upper Nitra. Some parts ofthe Western Carpathians continued to be unflooded during thePaleogene transgression. Up to now there is no evidence ofPaleogene sediments in the Spigsko-Gemerskd Rudohorie Mts and inthe Nizke Tatry Mts.

Geological Institute, Slovak Academy of Sciences, Bratislava,

CSFR

16

SOME COMMENTS ON THE POTENTIAL FOR USING CAESIUM RADIONUCLIDESTO INVESTIGATE OVERBANK SEDIMENTATION IN CARPATHIAN RIVERS

FROEHLICH, W.,(1 ), WALLING, D. E. (2)

The caesium-137 technique has been used widely for datingrecent horizons in lake sediment cores. The use of caesiumradionuclides to investigate rates of floodplain deposition maybe viewed as a logical development of its application. Thefloodplain surface will receive inputs of radiocaesium bothdirectly from atmospheric fallout and in association withdeposited sediment eroded from the upstream drainage basin.Overbank deposition on floodplains is likely to represent themajor transmission loss and a preliminary attempt has been madeto use caesium-134 measurements to document recent rates ofdeposition on the floodplain bordering the lower reaches of theHomerka Stream,3 d the main tributaries of the Dunajec River. Thepresence of Cs y lects only inputs of Chernobyl derivedfallout. Most of the Cs activity occurs, as expected, near thesurface. Some downward diffusion or migration has obviouslyoccurred (probably along macropores), but the profile shapeclosely reflects fallout inputs to the surface. At the time ofChernobyl fallout in mid 1986, the level which is now 14 cm belowthe surface would have been exposed at the surface and would havereceived fallout of caesium-134. Subsequent deposition ofcaesium-134 bearing sediment eroded from the upstream drainagebasin has buried the surface exposed in 1986 and the depositedsediment has increased the total caesium-134 inventory. Sincecores were colleited in Homerka 1989, annual deposition rates ofca. 4 cm year may be estimated. Similar rates of depositionhave been estimated for other floodplain locations within theDunajec River system, indicating that floodplain accretion iswidespread and that even in these high energy mountainenvironments, significant transmission losses may occur inassociation with floodplain deposition. Further work is, however,required to quantify the magnitude of the transmission lossesinvolved.

(1)Institute of Geography and Spatial organization, PolishAcademy of Sciences, Krakow, Poland

(2)University of Exeter, UK

17

GLACIAL STRATIGRAPHY AND DATING OF THE QUATERNARY ACCUMULATION

FORMS AND DEPOSITS ON THE FORELAND OF THE TATRA MTS

HALOUZKA, R.

Brief survey of complex morpho- and lithostratigraphicalanalysis of the Quaternary glaciogenic and glacifluvialaccumulation forms and sediments at the southern foreland of theHigh Tatra and West Tatra Mts (i.e. in the Poprad and LiptovBasins). Local mutual parallelization of the Quaternarystratigraphical successions inside the foreland. Scheme of theirconnection with the fluvial stratigraphical system of terracedeposits in adjacent or near areas of the Carpathian depressions(in continuity or correlation relations). Conclusion(interregional): general correlation of glacial stratigraphy ofthe Tatra's area with both glacial climatic-stratigraphicalscales of Europe (i.e. the Alpine and Nordic scales) and so alsowith their competent time scales (it is so called indirect datingof forms and sediments).

Dionyz ttur Institute of Geology, Bratislava, CSFR

18

DATING REPORT ABOUT QUATERNARY LATEST VOLCANIC ACTIVITY IN

CZECHO-SLOVAKIA (BAZALTS NEAR NOVA BARA-BREHY)

HALOUZKA, R., 9IMON, L.

Latest activity of final basalt volcanism (ttiavnicastratovolcanoe of central Slovakia). It is a lava flow ofnepheline basalts near Nova Bafta (between Tekovska Breznica andBrehy, effusion from the area of the present-day Putikov VrtokHill). The stratigraphy of basalts is mainly determined by theirgeologic-morphological position (on gravelous accumulation of thelowermost Hron River terrace). Radiometric dating by K-Armethod and analysis of paleomagnetism. Quaternary stratiographyin the valley, paleogeographical development.

Dionyz 9tur Institute of Geology, Bratislava, CSFR

19

MORPHOGENESIS OF GRAVITATION SLOPE DEFORMATIONS IN THE VIHORLAT

MTS (BASED ON PALYNOLOGICAL DATING)

HARdAR, J(), KRIPPEL, E.(2 )*

The Vihorlat Mts is a component of the East Carpathians. Itis built of Neogene volcanites with prevalence of andesites andtheir pyroclastics. Morphologically it represents a typicalvolcanic mountain range with landforms already prevailinglydestroyed to a considerable degree to the present. Typologicallyit is gebirgsland with absolute altitudes over 1 000 m. Typicalare, especially for northern marginal parts of the mountainrange, mightly gravitation slope deformations of various types.In this way "he valleyr were dammed and so they gave the rise ofsmall lakes, morasses and depressions. A typical example of thisfact are the small lakes Durova Mlaka, Male Morske Oko and Kotlikas well as the peat bogs Hypkaha and Postavka. All this areabelongs from the geomorphological and genetical view to one andthe same group of forms arisen in the Postglacial. The beginningof the rise of peat bogs is ordered by us into the initial phasesof the Holocene. The pollen analysis points out to the beginningof the rise of basal sites of the peat bog Hypkaa in thePreboreal Period, when in Central Europe it came'to the definitewarming of the climate as to the Postglacial Period. A definitecontraction of pine/birch stands and an onset of mixed onesbegin.

From the above mentioned it results that the processesproper, leading to the rise of slope deformations, occurred ina period before the Holocene, namely in the period of the LateGlacial. In the Pleistocene and Early Holocene very intensiveweathering and erosional processes occurred in the territory,connected with being incised as to the valleys, with the movementof weathered masses along the slopes and with theirtransportation into the valleys.

(1 )University of P.J.tafarik, Pre~ov, cSFR(2 )Institute of Geography, Slovak Academy of Sciences,

Bratislava, CSFR* Deceased April, 1992

20

THE SIGNIFICANCE OF INTERDUNAL DEPOSITS IN THE NIZZANA SANDS,SOUTHERN NEGEV, ISRAEL

HARRISON, J. B. J., YAIR, A.

Fine textured layers (primarily silt and clay) have beenobserved in the interdunal areas of continental sand dunes inarid areas. The origin of the fine textured deposits is importantin that they are found associated with sediments that consistpredominantly of sand size particles. The fine textured layershave been attributed to three main processes: a) high watertablesor springs which produce swamps in the interdunal areas, andresult in fine textured sediments, b) runoff from the duneswashes eolian fines into the interdunal depressions and c)overbank deposition from ephemeral streams which flood thedepressions. Each of these processes is a results of aniuncreased input of water into an arid environemnt.

The interdunal area between longitudinal dunes in Nizzana,in the Negev Desert, Israel, contains deposits of sand andisolated areas of fine grained (playa) deposits. A series oftrenches across the interdunal area exposed stacked sequences ofup to four buried, localised, playa surfaces. The former playasurfaces consist of couplets of more silty and more clay richlayers and these couplets are separated by horizontally layeredsandy deposits. Some of the couplets exceeded 1 m in thickness.

Morphological and sedimentary data suggest that the finetextured layers in Nizzana are the result of overbank depositionfrom the Nahal Nizzana and not high water tables or sedimentrunoff from the dune slopes. The fine textured layers areprobably reworked loess from the Negev highlands (the headwatersof the Nahal Nizzana) the deposition of which occurred in theMiddle to Late Pleistocene. TL dates of different clay layers atNizzana range from 40 000 yrs BP to 6000 yrs BP suggesting thatthe loess was still being reworked during the Holocene. Thepresence of these layers suggests the occurrence of largemagnitude flood events in this area in the late Pleistocene andHoloccne. The possible climatic significance of such floods isunder investigation.

Institute of Earth Sciences, The Hebrew University of Jerusalem,

Israel

21

THE EFFECTS OF TIME ON THE EVOLUTION OF GEOMORPHOLOGICAL CYCLES

IN THE NANIB DESERT, NAMIBIA

HEINE, K.

The influence of orbital parameters on climatic changes isdocumented by climate-sensitive facies of marine and terrestrialorigin. However, the longterm evolution of Namib landfoxitsappears not to reflect this climatic history with the obviousfrequency cycles. Rather, the landforms of the Namib point Ist tophases during which adjustment occur to the different cycles(e.g. the past 700-900 ka with 100 000-year cycles) and 2nd tophases during which the climatic setting is represented by thelandforms (characteristic desert forms). The resulting patternsof landscape development include relief persistence, stagnacy ofdevelopment, transient forms etc. In the Namib the cycles oflandform evolution rather seem to be a matter of physical modelsthan of climatic change.

Institute of Geography, University of Regensburg, FRG"

22

EVOLUTION AND RECOVERY TIME OF VOLCANIC LANDFORMS

INBAR, M.

There is a clear starting time of geomorphic development ofmonogenetic volcanic landforms, and the rate of developmentdepends on climatic and physiographic factors. Most of theobservations and studies of erosional processes after volcaniceruptions are short term and follow the first period after theeruption. Erosion rates are high, about three to four orders ofmagnitude above the normal erosion rates for non affected areas.Several years after eruption, initial rates decrease withstripping of the fine ash layer in pyroclastic eruptions,vegetation cover and development of a steady drainage system.

A comparative study was conducted in several volcanoes ofMexico, South America and Antarctica in order: (1) to examineerosion and sedimentation processes in pyroclastic cones andadjacent lava fields; t2) to identify revegetation processes andsoil development, and (3) to determine the changes in thedrainage system and rates of integration after eruption. InMexico, the Jorullo cineritic cone (1759) is covered by a densevegetation and its lava flow is in an early stage of vegetationcover and soil development. In the Paricutin cone (1943-1952),after the removal of the initial fine ash layer, there is nonoticed erosion. Following processes were observed: a)Revegetation started to promote soil development; b) In the lavafields the rate of erosion is very low, the drainage is internaland most of the flows have a fresh appearance; vegetation isdeveloping in crevasses and low places; c) Floodplains-"Llanos"-developed at the outlet of the dammed rivers by the lavaflows, and accumulation of sediments is still notorious; only oneof them integrated in the external drainage system; d) Erosionrates for the fluvial drained area are about 50 % higher thanadjacent similar areas in the region; deceleration was rapid inthe first 5 years after eruption.

Lava flows of the last eruption (1870) in the Ceborucostratovolcan have little veqetation cover and soil development.In the humid and subtropical forest area, pyroclastic flows andashfalls from the recent eruption of the Chichon volcano (1982)are already covered by a dense vegetation in large affected areasby the eruption.

In cold environments of the Southern Andes mountains ( Lat.40 S), the Escorial flow (400 yr. BP) shows a partial cover offorest. The recently erupted Navidad cineritic cone (1988) is atan early stage of development and wind erosion is the mainprocess. In Deception Island (Antarctica), there is a rapidmorphological evolution of cinder cones erupted in 1968-1970.

In all the studied areas most of the declining trend oferosion rates is of several orders of ragnitude during the firstyears after the eruption. Vegetation cover, soil development andintegration of drainage systems are slower processes which maylast hundreds or thousands of years.

University of Haifa, Israel23

GULLY EROSION AND ITS ROLE IN ENVIRONMENTAL DEGRADATION

(A CASE STUDY)

JHA, V. C.

In this paper an attempt has been made to find out thestages in break-up of the initial surfaces accelerating gullyerosion in the Lateritic Terrains of the Birbhum District, WestBengal, India, and the role of gully erosion in environmentaldegradation. The gully erosion is observed as dominant mechanismin creating environmental degradation in the study area andcosidered as serious geomorphological hazards. Three gullyerosion sites have been selected for the proposed investigationwhere the gully development have been taken place at the largescale. The lenght, width, depth, cross section, plan and profileincluding special features have been mapped with the help offield instrumente. The rate of gully erosion has also beenstudied in two different rainy times. A few of developed gulliesare anhropogenic in origin producting ecological imbalance in thestudy area. A lanscape ecology map of the Mohammad Bazar P. S.has been prepared based on considerations of the natural andanbropological aspects as well as the needs and processes ofgully development.

Visva - Bharati University, Santiniketan, India

24

FREQUENCY IN EROSIONAL PROCESSES AND ENVIRONMENTAL INFORMATION

KASHIWAYA, K.") OKIMURA, T.

(2 )

There have been several severe landslides and debris flowsby heavy rainfal, which caused natural hazards in the RokkoMountains of Kobe District. Most of the mountains are composed ofweathered granite which is fragile. Analysis of pond sediments,mainly composed of clay, during the past 40 years in themountains shows that coarser grains flowed into the 1 onds in thesevere landslide year, which is identified by using Cs.

Temporal change in heavy rainfall during the past 100 years(excess rainfall; annual summation of heavy rainfall over 100mm/day) in Kobe District has some dominant periods of conspicuous24-30, 10-13, and 5-7 years. The period of 24-30 years in thisarea corresponds to that of occurrence of the severe landslidesand debris flows by heavy rainfall; years of the maximum rainfallcorrespond to years when there have been severe landslides anddebris flows in the area.

Changes in three ring width in the same area during the past80-120 years indicate that most of the sequences have a dominantperiod of about 24-30 years. Coherencies between the rainfall andthe ring width at 24-30 years are very high, though there remainsome problems on causal relationship between them. These suggestthat the excess rainfall may provide a first approximation forexternal force which have developed erosional features and thattree ring width may be used as a proxy data for the force.

E

-40

-20

C 1880 1900 1920 1940 1960 1980YEARS

Figure 1. Time sequence in excess rainfall in Kobe District.Arrows indicate severe landslide years by heavyrainfall.

(1 )The Graduate School of Science and Technology, KobeUniversity, Japan

(2 )Faculty of Engineering, Kobe Univeristy, Japan

25

DEVELOPMENT OF THE MORAVA RIVER BED NEAR STRANICE (SOUTH

MORAVIA)

KIRCHNER, K., NOVAdEK, V.

Floodplains are ones of the most dynamically developednatural types of relief affected and remodelled by humanactivities (e.g.canaiization, dam building, etc.) at the sametime. Recently the wide flooplains with natural modellingprocesses (meandering) are rare from both ecological andscientific viewpoint in the Czech Republic. The floodplain of theMorava River near Stranice with natural river bed (meandering)belongs to valuable territories.In this region canalization ofthe river have not carried out yet. Hence we attempted todetermine a dynamics of the river bed development in thementioned area. Maps from different time levels were used andcompared with the present conditions. We employed historical mapsfrom 2nd military mapping (1836-40), maps from 3rd militarymapping (1876-77) and topographic maps (1960). Contemporarysituation was investigated with the help of detailedgeomorphoiogical mapping and remote sensing data. In the lastcentury the expressive meanders were not developed in the areainvestigated. In the second half of the 20th century theoutstanding meanders were originated within the framework ofmeander belt and their development was extremely accelerated. Inthe last thirty years this meanders have been cutted off bycontinuing erosion and moved.In this period undercut slopes haveshifted downstream approximately about 100-120 m, slip-off slopesabout 70-100 m. Owing to lateral erosion the lateral moving ofmeanders did apprimately 40-60 m.

Historical maps provide valuable informations aboutdevelopment of river bed and for dating of young alluvialdeposits. Research area enables to link historical data to nextinvestigations of river bed and floodplain landforms. It isnecessary to establish nature and to forestall a rivercanalization.

Institute of Geography, Czechoslovak Academy of Sciences, Brno,CSFR

26

LATE-HOLOCENE SLOPE DENUDATION IN THE POLISH TATRA MOUNTAINSSEEN IN THE LIGHT OF LACUSTRINE SEDIMENT STUDIES

KOTARBA, A.

Overdeepened mountain valleys filled with lakes are naturaltraps collecting sediments that were washed down fromgranodiorite debris slopes during the Holocene. Lacustrinesediment cores were recovered from the Czarny Staw Lake (1621m a.s.1) and Zielony Staw Lake (1672 m a.s.1) in the GasienicowaValley, High Tatra. Both lakes are adjacent to debris flowaffected talus slopes. Gyttja type sediments (content of organicmatter 20-25%) are interbedded with minerogenic layers (contentof organic matter 1-5%). X-ray radiography of the sediment coresfrom the lakes was utilized to reveal the vertical bulk densityvariation and the structure of the sediment layers. Grain sizechanges in the cores are interpreted as sedimentation variationduring quiet periods separated by periods with extreme events onthe surrounding debris slopes. The layers of sandy andsandy-silty layers produced by turbidity currents, recognizedwithin gyttja are directly related to debris flow single eventsor periods of events.

The mean rate of deposition during the Holocene (0,15-0,2mm/yr) gives only a general idea about sedimentation rate. Realvalues are changing in successive time spans. It was evidentlyfound that substantial debris flows occurred in the TatraMountains during the Little Ice Age. Sedimentation rate for theperiod from about 1300 A.D. to 1860 A.D. is as high as 0,36mm/yr. coarser sediment pulses at that period suggest that atleast six extreme events or periods of debris flow activityoccured in the High Tatra Mountains. The most important event wasthe last one (ca 1840-50), and is correlated with the largest andrelict morphological features (debris flow levees, tongues,gullies) dated by lichenometry on the surrounding slopes.

Institute of Geography and Spatial Organization, Polish

Academy of Sciences, Krakow, Poland

27

YOUNG LANDFORM DATING BY USING OF CAESIUM-137

LEHOTSKY, M.

Agriculturally utilized landscape is one of the most dynamicsemi-natural system. As to the dynamic and experimentalgeomorphology the study of young landforms and processes are veryinteresting in this type of landscape utilization. Researchesconcerning arable land development and management are actual notonly from the scientific point of view but these studies havegreat importance in the practice too. In the last decades forthis purpose so called caesium-137 method has been begun toutilize. This procedure serves for the determination of the rateof erosion-accumulation processes during last 35-40 years as wellas for the dating of very young landforms which can be identifiedonly due to very detailed geomorphic mapping. Utilizing thismethod it is possible to distinguish as to the shape very similarbut as to the genesis very different landforms too. Examples ofa colluvial fan (tuborda stud, area), moderate undulatedtoe-slope part (Bzince study area), bottom of dell and very youngslope microbasin (Voderady study area) and dell bottom subsurfaceundulation (Pata study area) are presented.

Institute of Geography, Slovak Academy of Sciences, Bratislava,

CSFR

28

TIME, MAGNITUDE AND FREQUENCY IN CONTEMPORARY GEOMORPHOLOGY

(SOME THEORETICAL ISSUES)

LI, Y. Q., JU. X. M.

Much of our current understanding of the magnitude-frequencycharacteristics of geomorphological events derives from the workundertaken by Wolman and Miller (1960), who contended that mostsediment transport is achieved by intermediate events of highfrequency, though the semiarid environment could well present asan exception, where extreme events tend to be far more important.Event timing and landscape recovery were later added by Wolmanand Gerson (1978) into the consideration, both factors thought tobe also significant controls on the geomorphologicaleffectiveness of an erosive event. Time, magnitude and frequencyare three main concepts central to the tenets of contemporaryprocess geomorphology, though their true significance in ladformdevelopment still remains to be fully defined. Much existingcontroversy over catastrophism, uniformitarianism and equilibriumattests to the present deficiency of our knowledge about theforces-over-time problem and, until some thorough understandingis reached, present process studies as providing a key tolong-term landform development will remain as an unfulfilledpromise in the earth sciences (Douglas 1982).

Applicable landform evolution models are difficult todevelop, if no detailed field evidence is available to test them.This is probably true of the prepositions Thornes and Brunsden(1979) prescribed for geomorphology, and indeed also ofBrunsden's (1991) latest ten commandaments of geomorphology.Based on a wide range of field observations from many parts ofthe world, this study sets out to provide a critical rewiev ofsome of the theoretical issues concerning time, magnitude andfrequency in geomorphology. Emphasis is placed on severalwidely-held views and future directions for further research areoutlined.

TGRG, Central Academy of Drama, Beijing, China

29

TIME IN THE EVOLUTION OF SEMI-ARID CATCHMENTS

(THE LOESS PLATEAU MODEL)

Li, Y. Q., Ju, X. M.

Based of field observations in Wyoming, USA, Schumm andHadley (1958) put forward a model of semi-arid erosion cyclewhich arranged three distinctive catchment landforms types,namely: catchments being deeply entrenched at the outlet,catchments having actively eroding source tributaries, andcatchments experiencing aggradation in the lower reaches, in asequential order to generalize how the catchments have evolved intime. Erosion is thought to begin from the outlet and with time,the belt of maximum erosion migrates upstream, more channelscreated in the process. Active lowering of the source areas andgradual aggradation in the lower reaches finally lead to arelatively uniform catchment relief, which completes an erosioncycle. It follows that the Schumm and Hadley model isparticularly applicable to places of relative tectonic stabilitywhere deposition also occurs in great quantity in the lowlandareas. Modification to the model is necessary if either of thesetwo conditions does not hold.

The vast Loess Plateau in NW China is a semi-arid regionthat has underwent periodical tectonic uplift throughout theQuaternary, further, the sediment delivery ratio in the areagenerally approaches to unity (see Walling 1983), due to anefficient gully conveyance system, the fine loessial particles ofa low settling velocity and the flashyness of extreme floods. Theloess catchment development is shown to follow a unique sequenceof evolutionary stages.

TGRG, Central Academy of Drama, Beijing, China

30

STABILITY - THE FUNCTION OF TIME

LIKHACHEVA, E. A.

Stability is a property of relief to preserve its diversestate character for significant periods of time duringenvironment changes. This period of time can be defined as "thetime of stability".

"The time of stability" during natural development of relieftI depends on a number of factors: age of landforms (A), form'sdimensions (D ), lithology of rocks (L), tectonic conditions (T),climate of the area (C), stability of the adjacent landforms(S1 ). All these factors can be presented in the following form:

t I = f (A, DI, L, T, C, Sl)

"The time of stability" of relief having undergoneanthropogenic influence is determined first of all by thestability of natural relief (its time of stability) and then bycorrelation of dimensions of landforms, and the degree ofinfluence (D = Dl/D2 ) ,time of influence (t1 ), intensity ofinfluence (i). The latter is defined by the degree oflithological, climatic, tectonic changes, and also changes of theadjacent landforms (S2 ).

"The time of stability" of the anthropogenic relief can bepresented in the following form:

t2 = f (t, D, t1 , i, $2) ,

where t 2 can be equal to tl, or more or less than t1 , that isdetermined by the level of management - activities on rationalmanagement of agriculture, techniques, and their interactionswith relief. Hence, plans should be worked out to regulate "thetime of stability", activizing or lowering naturalgeomorphological processes.

Institute of Geography of the Russian Academy of Sciences,

Moscow, Russia.

31

FIRST-ORDER 14C DATING OF THE COASTAL RANGE, EASTERN TAIWAN

LIN, J. CH.

The purpose of this study is to produce a chronology of theneotectonic landforms of the Coastal Range using absolute datingtechniques in order to (a) test the assumptions of the tectonicmovement model; (b) determine the absolute ages of the raisedbeaches and thereby ascertain the degree of coastal deformationto be incorporated in tq model.

The First-Order C dating method has been adopted toobtain these chronological data. It involves sampling,uetreatment, extraction of 1 4C and determination of the rate ofC decay. The samples used are mainly from coral and shells as

their original environment of deposition is known. The intertidalzone where these samples originally inhabited is readilyrecognised and therefore provide a good indicator of the effectof the neotectonic regime U coastal landforms.

From the results of C dating, it has been shown that thecoastal area has a differential uplift rate ranging from 0,4 to4,4 mm/yr in a non-linear relationship. The difference betweeneach different sampling section, and the clear evidence of faultcontrol demonstrated by reference to the structure of the area.The Coastal Ranges is not being uniformly uplifted.

National Taiwan University, Taipei, Taiwan

32

GEOMORPHIC PROCESSES IN THE LIGHT OF QUATERNARY BIOSTRATIGRAPHY

LOZEK, V.

The development of biocoenoses is affected by relief changesin time and space. Biostratigraphic analyses of depositionalsequences thus may throw light on geomorphic processes whichcontrolled their formation. They provide information on thefollowing aspects of particular processes and events: /1/geological age, /2/ rates of deposition or erosion, /3/reconstruction of environments, /4/ estimate of accumulated oreroded soil volume. Most favourable conditions occur in karstregions or lime-rich areas where fossiliferous series aredeveloped in a wide variety of facies and position. Within thetime span Pliocene-Pleistocene particularly large-scale processesand events can be traced, e.g. the process of valley formation onthe basis of terrace sequences which enable erosional,depositional as well as standstill phases to be distinguished, orthe process of karstification reflected by the cave fills ofvarious age. Sedimentary fills in cave eiiLrances androck-shelters are strongly affected by sheet erosion and sloperetreat. Valley floor sediments date the last phase ofdowncutting and reflect in detail the Postglacial climaticdevelopment. Tufa deposits with soil or scree intercalationsrecord the history of scree accumulation phases alternating withprecipitation of pure CaCO corresponding to standstillintervals. During the last 7 millenia anthropogenic impacts canbe documented by the correlation of archaeological findings withbiostratigraphically treated sequences. Our data demonstrate areasonable relationship between the relief changes andbiostratigraphic data whose correlation may considerablycontribute to the knowledge of landscape development.

Institute of Geology, Czechoslovak Academy of Sciences, Prague,

CSFR

33

VOLCANITES-SCULPTURAL LANDFORMS INTERFERENCES IN THE ROMANIAN

VOLCANIC MOUNTAINS (PREMISES FOR DATINGS IN GEOMORPHOLOGY)

MAC, I., IRIMUS, I.

There are numerous interferences between volcanites andsculptural landforms both on the interior of volcanic mountainsand on their border with The Transylvanian Basin.

The overlapping and interference of volcanic products withpolycyclic levelled surfaces from Mount Metaliferi permit theestablishment of their age.

Similarly, the interferences which appear at the level ofaccumulation fluvial forms in valleys of the Aries, Ampoi, Oltand Mures River are evaluated and chronologically differenciated,stating in this way the morphogenesis periods. Taking intoconsideration the fact the manifestation of magmatic-volcanicprocesses took place successively from the Badenian to thePleistocene, the temporal scale of the datings has a very widegauge.

In this way dating could have been extended for otherregions too, regions which were not affected by volcanism buttheir evolution took place in the same time and in the samemanner as the interference regions of volcanism with exogeniclandforms.

Babes - Bolyai University, Cluj-Napoca, Romania

34

RATE AND DYNAMICS OF CONTEMPORANEOUS EROSIVE PROCESSES INDUCED BY

THE SURFACE RUNOFF IN HIGH MOUNTAINS OF THE WEST CARPATHIANS

MIDRIAK, R.

Research was carried out by the deluometric method, e.i.direct measurements of the surface runoff, its turbidity and anamount of the soil loss.

Results of studies are very different according to a kind ofground surface and/or a vegetation cover. Minimum of surfacerunoff i3 in the spruce- and dwarf-pine stands where from 87,4 to189,1 m of water is outflowing per hectare per annum. Duringthat runoff (with the turbidity of 0,13 g load per litre) 39 to152 kg.ha -. yr- of soil 3 is 1ssed1

Ther? is 210,8 m .ha- .yr- of suiface1 runoff, an average0,14 g.l-of turbidity and 169 kg.ha .yr of the erosive soillosses on the both bare places in forest stands and uprooted treeplaces. From the surface of the grass-covered subal~ine andalpine belt an amount of the urfaye runoff is 222,1 m and thesoil loss is only 59 kg.ha .yr- . A great deal of soil isremoved by the surface runoff from the ground with a thinvegetation cover within the forest and the subal~ine belts (e.g.'ski routes). The runoff on that ground is 327 1 ad soil loss3 437 kg.ha-l.yr-1 . Maximum of the rynoff (632 m .ha .yr- ) withthe turbidity of 0,41 - 0,61 g.l- is on the disturbed soilmantle aboye thT timberline. There are soil losses as much as 4556 kg.ha-. yr- there.

Time distribution of soil losses by seasons in the forestand dwarf-pine stands: spring 20 to 36 %, summer 26 to 42 %,autumn 22 to 36 %, winter 11 to 22 %. On the bare and destructedsurfaces above the timberline a great deal of erosive soil lossis displaced during summer (52 % on the average). Frequency ofsevere soil losses occurrence in the area above the timberline isonce for 2 to 15 years in the Tatra Mts or once for 25 to 30years in other high mountains of the West Carpathians,respectively. The frequency is mostly identical with theoccurrence of heavy rains of rate 100 mm per 24 hours and more.

Technical University, Zvolen, CSFR

35

MAIN STAGES OF THE WEST CARPATHIANS GEOMORPHOLOGICAL EVOLUTION

AND THEIR DATING

ONDRA9IK, R.

The West Carpathians are characterized by mountain rangesand basin topography. The last comprehensive concept of theirgeomorphological evolution had been set up thirty years ago byLuknig and Mazur. Their interpretation was based on the ideas ofthe alpine and the following germanotype tectogenesis. Laterdiscoveries have not proved the validity of their interpretationin all aspects. Among such discoveries belong e.g. thedifferential uplift of granitoid bodies occuring since theCarboniferous-Permian period in the Inner West Carpathians andsince the Neogene period in the outer parts of the Inner WestCarpathians, the depth and shape of the Moho-discontinuity, thesouth-east dipping of textural planes in the litosphere of theInner West Carpathians, differential kinematics of the Neogenesubduction of basins based on chronostratigraphy of fillingsediments, the role of gravitational tectonics in thegeomorphological evolution of various areas and its correlationwith the distribution and development of slope deformation, etc.

A more convenient framework for the interpretation of theabove-mentioned discoveries and their correlation with thegeomorphological evolution of the West Carpathians represents theprinciples of the new global tectonics. The adaptedinterpretation of the West Carpathians geomorphological evolutionwith the definition of the main stages and their dating, is to bepresented for discussion.

Comenius University, Bratislava, CSFR

36

ARCHAEOLOGICAL DATING, GEOMORPHOLOGICAL RECONSTRUCTIONS AND

PALAEOCLIMATIC CORRELATIONS IN NORTHERN SPAIN

PERA, J. L., CHUECA, J., JULIAN, A.

The datings carried out by geoarcheological techniques inslopes and infilled-valley deposits located in northern Spain,have allowed us to establish several evolutive sequencesresulting from the alternance of fill and downcutting stages.Such sequences are due to environmental changes mainly generatedby climatic variations during the oldest phases (UpperPleistocene-Holocene), or by the combination climate-anthropicactivity along the Upper Holocene. In this area the bestchronological and palaeoclimatic information is given by slopedeposits, linked to the clear individualization of differentstages provided by the existence of intermediate downcuttings.Besides, processes that originate slope-regularizations are moreeasily related that infilled-valley ones to particularthermopluviometric and environmental conditions.

Following these geoarchaeological criteria, we identified instudy area several evolutive sequences developed along the UpperPleistocene and Holocene that permit the outlining of a firstchronological approximation to the palaeoclimatic characteristicsof a broad area placed in the northern Spain (Ebro river basin).This data, basically obtained in the lowlands, has been relatedto the climatic phases previously established - through the useof absolute dating methods, palynology, lichenometry, etc. - forthe two neighbouring and marginal mountainous ranges (Pyrenes,Iberian Chain), and confirm the existence of a high degree ofsimultaneity among palaeoenvironmental events developed in bothareas.

Zaragoza University, Spain

37

CONTEMPORARY TRENDS OF THE RIVER CHANNEL BEDS

(CASE STUDY FROM ROMANIA)

RADOANE, M., ICHIM, I.

Our study occurs to discuss the contemporary trends of theriverbed dynamics of almost the whole area of the EasternCarpathians. The quantitative data represent the measurements ofthe maximum river depth in over 70 cross sections from 42 streamsover periods between 11-30 years. The data were elaboratedgraphically to facilitate the study of the phenomenon behavior intime, to apply some techniques of the time series statisticalanalysis and, finally, to favour the comparison of the trends. Wealso viewed the analysis of the discharge regime to establish themain causes that favour some trends of the riverbed dynamics.Also, we analysed the channel deposit's variability related tothe long profile form.

The linear tendency of the vertical riverbed dynamics wasevaluated by means of a time functionb: y = a + b.x, wherey = riverbed elevation in centimeters and x = time in months. Weconsidered that the degradation tendency is expressed by thenegative values of the regression coefficient, the aggradation bypositive values and a certain stability by the values of thecoefficient close to zero. We used the regression coefficientvalue (b) as index of the vertical riverbed mobility in theconsidered area. By means of these values we evaluated thedominant riverbed process (degradation, aggradation) andstability in the 73 cross section. The same coefficient value (b)enabled us - through the repartition frequency - to noticethat: degradation is most frequent of the riverbed processes inthe Eastern Carpathians.

The polynomial trend in the vertical riverbed dynamics wsdetermined by means of the polynomial functions of the 2nd, 3rd

,

4t h order. They indicate an existence of aggradation -degradation cycles, which are superposed on the general trends(uplifting and sinking) of river channels.

The periodical components of the series referring to theriverbed elevation were determined by means of the spectralanalysis.

Final conclusions of the paper are related with arealdistribution of the riverbed mobility and with main controllingfactors.

Research Station "Stejarul", Piatra Neamt, Romania

38

ELECTRON SPIN RESONANCE (ESR) DATING IN GEOMORPHOLOGY

RADTKE, U.

ESR dating has been systematically applied in earth sciencesand archaeology since 1975 when IKEYA dated a stalactite fromJapan. In the meantime this relatively new technique has beensuccesfully applied to the dating of material such asspeleothems, mollusc shells, corals, tooth enamel and quartz. Themajor emphasis of this "state of the art" paper lies on theoutline of the application of ESR dating in geomorphology.Besides these general topics special emphasis lies on thepresentation of ESR dating results from coral reef tracts asa tool in timing and reconstruction of the Quaternary sea-levelcurve. Examples and unpublished data from Papua New Guinea, theislands Kikai-Jima and Hateruma (Japan), Sumba (Indonesia),Barbados and the atolls Rakahanga and Pukapuka (Cook Islands) arepresented. ESR dating of corals covers at least the whole Middleand Lower Pleistocene and the Holocene. The precision of thetechnique allows to distinquish between isotopes stages 5a, 5c,and 5e. For samples from stages 5 to 9 the precision of repeatedanalyses were in the range of 10 %. Samples from stages 11 to 17display an increasing age scattering. ESR dating of coralsextends the dating range of the U-series dating methods up to atleast 600 000 yrs B.P.

Institute of Geography, H. Heine University, Dusseldorf, FRG

39

TIME AND FREQUENCY OF SLOPE EROSION EVENTS IN NORTHERN MOUNTAINS

RAPP, A.

Based on field studies in Scandinavian Mountains andSpitsbergen in the 1950's and later the dating and frequency ofgeomorphic events will be discussed in this paper. Twoaltitudinal zones of debris slopes will be high-lighted: 1)blockfields (felsenmeer) on high plateaus and 2) talus slopes onvalley sides. It is argued that in north Scandinavian Mountainsthe felsenmeer of altitudes above ca 1200 m a.s.l. and an annualmean air temperature of below -4 C are a zone of very slowglacial and periglacial geomorphic development, due to conservingpermafrost and cold-based glaciers. The middle-alpine altitudebelt of ca 600-1200 m is a zone of more rapid geomorphicdevelopment, as shown by case studies in the Abisko area, northSweden.

University of Lund, Sweden

40

MAGNITUDE, FREQUENCY AND DATING OF FLOODS - SOME QUESTIONS AND

INITIAL ANSWERS FROM A STUDY IN THE NEGEV DESERT, ISRAEL

SCHICK, A. P., GREENBAUM, N.

Several extraordinary floods, often but not always with amarked geomorphic effect, have been identified and studied inseveral parts of the world's arid zone. Among these, several hadoccurred in the veritably dry ("hyperaid") belt of the MiddleEast and were studied in some detail: the 1966 Ma'an Flood(Southern Israel & Southern Jordan), the 1971 Mikeimin Flood(Southern Sinai Peninsula), and the 1975 El-Arish Flood (Sinaiand Negev Deserts).

While estimates of the magnitude of these and other similarfloods in deserts elsewhere vary considerably according toscientific, technical and logistical constraints, the problem ofthe frequency of these events presents even greater difficulties.One method, recently developed by the Arizona school ofgeomorphology and adopted since by several other groups, usessedimentation relics of historic and even prehistoric floods forradiometric dating in conjunction with the reconstructed peakflow channel cross section and hydraulic characteristics. Therelics, called paleo-stage indicators (PSI), are mostly in theform of slackwater deposits (SWD), which offer relativelyabundant and reliable chronostratigraphic evidence to enable anadequate statistical analysis of frequencies.

In a study currently in progress in the Central NegevDesert, a flood in the 1400 sq km catchmnet of Nahal Zin, whichexceeded the highest flow observed during the instrumental periodof the last 40 years by a fa.7tor of more than 2, has been datedat 885 y BP. Although questions of temporal stability - both ofchannel geometry and of climate - do present themselves, thecontinuation of the study is bound to shed new light on themagnitude-frequency relationship of desert floods and, throughthese, on the basic controversy of the magnitude-frequencybalance in geomorphic processes.

Institute of Earth Sciences, Hebrew University, Jerusalem,

Israel

41

MAN'S ACTION AND SLOPE EROSION. THE CATASTROPHE IN AROSA (1981)

de SERPA MARQUES, B., de SOUSA PEDROSA, A.

When a catastrophic landslide occurred in a small riverbasin on the left bank of the Tamega Valley, in the Northeast ofPortugal, which involved the sudden sliding of several tons ofarable land and rocks and caused the destruction of a house andthe death of some twenty people in 1981, the authors decided tocarry out a careful investigation of this geomorphologicalphenomenon.

After having formulated a number of hypotheses, they did alot of fieldwork in the area and carried out measurements todetermine, as accurately as possible, both the real extension andthe causes of the occurence of such a phenomenon in thatparticular place and at that particular time of the year.

A series of studies enabled the authors to come theconclusion that both natural and human-induced causes had beenresponsible for the disaster.

Among the conclusions they reached, they would like toemphasize the following:

1 - the sharp angle of the slope;2 - a long period of heavy rainfall;3 - the long-term use of the valley for agricultural

purposes which interrupted the talweg as the bed of thesmall temporary brook had long been used to produce cornand vegetables;

4 - the destruction of the natural system of drainage ofrainwater, specially important in years of unusuallyheavy rainfall;

5 - the recent deviation of the runoffs to avoid theformation of rills in a newly-rebuilt road leading tothe local farms; this deviation favoured the flowing ofthe runoff to the primitive valley axis, now turned intocultivated land, as it has already been said above;

6 - the construction of a building right at the bottom ofthe mentioned valley, so breaking off completly thenatural flow of the water.

Disasters like this don't unfortunately constitute isolatedincidents. Therefore, the authors think it is very important tostudy the local geomorphology carefully before any localauthority begins planning or allows the building of houses or thesetting up of any human activity within the territory it isresponsible for.

Faculdade de Letras do Porto, Portugal

42

UTILIZATION OF THE PEDO-GEOMORPHIC APPROACH IN A STUDY OF VALLEYNETWORK CHANGES (ON THE EXAMPLE OF THE GIDRA CATCHMENT IN

THE DANUBE LOWLAND)

STANKOVIANSKY, M., LEHOTSKY, M.

This contribution is devoted to changes of spatialdistribution of valley network in the lowland part of the Gidracatchment in one of the loess islands of the Danube Lowland.

The Gidra River is predominatly a lowland flow. It issues inthe Male Karpaty Mts, which is a positive horstlikemorphostructure. The length of the flow in the mountains is 10km. Leaving the mountains down to tectoniclly dropping negativemorphostructure - the Danube Lowland - the flow runs in a lengthof 28 km across the TrnavskA Pahorkatina Hilly Land, which is oneof islands representing an upper step of the lowland. The GidraRiver is cut into its proluvial fan below the foot of the MaleKarpaty Mts and downwards (to Cifer) crosses the hilly step builtof the Neogene sediments, covered by loess loams. Below Cifer theGidra River flows across the region of the Trnavska Tabula Table,built of the Neogene sediments covered on average by a 16 m thicklayer of loess. It flows into the Dudvah at Mala Mada. In itslowest part, the Gidra River is situated in a tectonicllyconditioned longitudinal depression prolonged in the direction ofthe flow (NW - SE), the width of which is 3-4 km.

There has been elaborated a hypothesis of the repeatedchanges of river network in this region on the basis of resultsof the detailed geomorphic investigations connected witha mapping to the scale 1 : 10 000 and an analysis of the valleynetwork pattern of the Gidra catchment in the above mentionedtectonic depression as well. The hypothesis has been based on anassumption of stagelike migration of the Gidra River valley fromSW margin of the depression towards NE. Evidence for sucha hypothesis is the presence of soils with a mollic diagnostichorizon (fluvi-haplic phaesol) in abandoned flowless valleys.

Institute of Geography, Slovak Academy of Sciences, Bratislava,

CSFR

43

FLOOD FREQUENCY DURING THE HOLOCENE IN THE UPPER VISTULA BASIN

(BASED ON SEDIMENTS, FORMS AND ABSOLUTE DATINGS)

STARKEL, L.

The detail examination of sediments and forms anddetermination of their age make possible only rarely todistinguish the beds deposited during single floods and much moreoften to constate the long-term tendencies of changes in theflood frequency. The best sequence of big floods may beinvestigated in the near-channel zone of levees or slack-waterdeposits. On the contrary the registration of long-term changesis much better in facial variations on the flood plain and in thecreation of cuts and fills combined with avulsions and changes inthe channel sizes. The radiocarbon method help to approximate theage of events (up to one century). The black oaks correlated bythe dendrochronological method make possible to distinguish evenseparate floods.

In the upper Vistula basin a more detail picture of floodfrequency may be reconstructed for last 2 centuries as well asfor the transition between The Boreal and Atlantic periods.Facial and channel pattern changes as well as frequency of blackoak deposition help to identify phases of the higher floodfrequency: end of The Younger Dryas, 8700-7700 BP, 6600-6000,5200-4900 4550-4350, 3300-2850, 2350-1650 BP, V-VIc AD, X-XIc ADand from XVIc. New records slightly changed a previous author'spicture from 1983. The flood phases correlate well with otherrecords on glaciers, lakes, vegetation etc. The evaluation of therole of the human intervention in the flood frequency is stillopen.

Institute of Geography and Spatial Organization, Polish Academy

of Sciences, Krakow, Poland

44

DATING AND FREQUENCY ANALYSIS OF GEOMORPHOLOGICAL PROCESSES USING

DENDROGEOMORPHOLOGICAL METHODS

STRUNK, H.

For the past three years, we have evolved and re-examinedseveral dendrogeomorphological methods for frequency analysis ofdebris flows. For this purpose we analysed about 200 buried and260 undisturbed spruces (Picea abies) from five study areas inthe Alps. Additionally, we hawe excavated 40 buried spruces downto the orginal root systems and found that all these trees reacteven to a slight accumulation of debris by suppression, which isa pronounced decrease in growth. Consequently, several burialevents cause several phases of suppression. Thus, for each eventthe time of burial can be dated by determining the firstnarrowing of annual rings in the trunk with a precision of +/

0 to + 3 years.Since growth-ring sequences may vary from normal to reduced

or widened tree-ring diameters even in undisturbed trees, due toclimatic variations, it is indispensible to establish astandarized curve of normal growth conditions in each study area,representing the arithmetic average of the tree-ring width inevery single year as obtained from about 40 dominant undisturbedtrees. This curve helps to distinguish climatic variations in thewidths of growth-rings from those due to burying by debris.

With the help of phase-diagrams of suppression from 140buried spruces on a debris flow cone we can reconstruct thespatial distribution of each of 12 debris flow events havinghappened since 1830. The medium recurrence interval of debrisflows on this cone is about nine years between 1884 and 1989,with the length of intervals ranging between six and 13 years.

Though among all dating methods the dating of so-calledscars', injuries of the cortex of trees caused by the collision

with boulders during debris flows shows a very high precision of+/_ 0 to + 1 year, similar injuries may be caused by avalanchesand timber transport. The most reliable among several currentdating methods proved to be the determination of the year ofsprouting of the oldest root in each horizon of adventitiousroots and of the start of suppression in tree-ring sequences ofburied trees. Both methods work with a precision of +/_ 0 to+ 3 years.

Institute of Geography, University of Regensburg, FRG

45

CYCLICITY AND FREQUENCY OF LANDSLIDES IN ROMANIA

SURDEANU, V., ZEMIANSCHI, S.

Landslides represent one of the major erosional phenomena inRomania. There were several researchers who have made onlyascertain approaches, as far as their frequency and spatialdevelopment is concerned.

They rely on historical documents, pollen dating and C1 4dating. They also underlined the role of the Riss-Wurminterglacial for the Holocene evolution in order to state the ageand importance of landslides on hillslopes.

On the basis of an over 150 years of climatic records andby stating the periods of maximum humudity, they came to theconlusion that there existed at least three periods of maximumdevelopment of the process: 1912-1914; 1940-1942; 1970-1972.During the last period the process had a great extension inTransylvanian Tableland, Moldavian Tableland, OrientalCarpathians and Subcarpathians. It was predicted that at the endof the millenium there will be another cycle of intense activityof landslides.

On the background of this major cycles there were othersmaller cycles of about 3,7 and 13 years which reactivated oldlandslides.

Finally, the topometric and inclinometric measurements showvery clearly the existence of seasonal cycles of this dynamicprocess.

After examining the spatial distribution it comes out as afact that high frequency of the process appears on regions inwhich lithology is very rich on clay components.

Babes-Bolyai University, Cluj-Napoca, Romania

46

A NEW APPROACH IN UNDERSTANDING OF GEOMORPHOLOGICAL TINE

TIMOFEEV, D. A.

In geomorphology the problem of time is not only associatedwith the age dating of relief according to the scale of absolutetime. On the assumption of scientific views of Vernadsky, timealong with space is regarded as structural discrete - continuouscategories. There can be distinguished a) the time of individualbeing - the time of development of separate form of relief, orits elements; b) the time of species - the duration ofgeomorphological landscape development, or types of relief; c)the time of evolution - the periods of time corresponding toparagenetic complexes of types of relief and embracing periods ofgeomorphological cycles. Every elementary morphological unit ofthe surface, every form of relief, a geomorphological landscapehave been existing in their own spacial time. Every spatial- genetic and morphodynamic category of relief reflects the wholecomplex of events; daily, seasonal, of many years, secular,stages and cycles. These events can be of slow, continuous,evolutionary character, yet they can be changed by catastrophicperiods of active life, separating periods of relief or absolutestability, when the time for a particular object (a form orprocess) disappears. The geomorphological time is able to compresor widen, to accelerate or slow down in the dependence on theforce and the number of events.

For ecological geomorphology it is very important toestimate the intensity and the recurrence of geomorphologicalevents and the prognosis of possible consequence of these events.The absolute (geological) time can be regarded as an instrumentof geomorphological events, changes of processes, forms and setsof forms of relief. The study of dicrete geomorphological time asone of the factors of morphogenesis - is the key to understandingof morphodynamic mechanism.

Institute of Geography of the Russian Academy of Sciences,

Moscow, Russia

47

AGE AND TIME OF RELIEF: RESULTS OF THE IRKUTSK CONFERENCE 1991

TIMOFEEV, D. A.(' ) , UFIMTSEV, G. F.

(2 )

The conference of the Soviet geomorphologist "Age and Timeof Relief" was held in Irkutsk (East Siberia) in September 1991.There were discussed diverse aspects on the problems of time ingeomorphology: theoretical, methodological, regional. In thefield of theory and methodology the discussion was focused on thetwo main problems: 1) the notion "geomorphological time" and itsassociation with philosophical interpretation of time; 2)principles and methods of geomorphological chronology and the agedating of relief. There was presented a concept of discrete- continuous aspect of geomorphological time, associated withdiscreteness of geomorphological space, discussed the role ofevents in the history of morphogenesis. There was proposed todistinguish periods of active life of geomorphological systems ofany range and periods of their passive state or rest. Theimportance of the recurrence of geomorphological events andabsolute age dating was emphasized. Hence, the theory ofgeomorphological cycles was assessed from the new point of view.In accordance with it there were expressed traditional ideasabout the continuity of absolute (astronomic, geological) age,the continuity of relief-forming processes development. The newresults of regional studies of some areas history development ofEuropean and Asian parts of the country, particularly Siberia,were also reported. The new data, including absolute age datingsof river valleys and terraces of the Enisey Basin and the BaikalDepression were presented.

All in all the conference outlined the actuality andinsufficient elaboration of the problem "time in geomorphology",revealed the existing difference of opinion in the theory andmethods of investigation.

1)Institute of Geography of the Russian Academy of Sciences,Moscow, Russia

(2)Institute of the Earth's Crust of the Siberian Branch of theRussian Academy of Sciences, Irkutsk, Russia

48

HISTORICAL APPROACHES TO GEOMORPHOLOGICAL DATING

TRIMBLE, S. W.( )', COOKE, R. U(2)

Many questions of time in geomorphological processes can beilluminated by examining the historical record of the pastcentury or so. The recent past sets the stage for contemporaryprocesses, which may not be fully intelligible without anappreciation of the past. Extrapolations of process rates andpredictions of future changes may require records that are ofsufficient duration and accuracy to allow the segregation ofshort-term and secular trends. The causes and consequences ofhistorical environmetal changes are often fundamentally differentfrom paleoenvironmental events because of the unique and oftenunpredictable role of human activity.

Many landforms adjust to changing environmental conditionsover decades. Such adjustments are often very difficult to studyfrom field evidence alone. Historical sources are thereforepotentially invaluable not only for calibrating the nature,rates, and locations of medium-term changes, but also forexploring the dynamics of geomorphological systems and theirrelaxation and reaction times, thresholds, and equilibria. Morethan that, historical sources may provide the only evidence ofthe causes and management contexts of change that are fundamentalto understanding present landforms and developing the theory andpractice of environmental management.

This paper provides a brief introduction to the enormousrange of potentially useful dating sources. We recognize 11 broadtypes of information: travel and exploration accounts; newspapersand journals; instrumented land surveys; topographical surveys;geological, soil, and soil erosion surveys; aerial photographs;ground-based landscape photography; land-use data; drainage andirrigation records; climatological data; and stream and sedimentdischarge records. Examples from each category are given anddiscussed.

(1 )University of California, Los Angeles, USA

(2 )University College, London, UK

49

GEOLOGICAL AND OWN TIME OF RELIEF

UFIMTSEV, G. F.

Geomorphology uses, commonly, the geological time, which, inthis case, has attributes of the Newton's absolute time. It haswell elaborated metric and is used under reconstructions ofmorphogenesis of the past or under study of the moderngeomorphological processes where the following calculations usethe ideas of classical mechanics. The formula is used "... reliefin space and time ...".

The recognition of unity of space-time of relief demands ofcreation the theory of relational (own) time of relief which isbuilt on the base of properties and relations of its forms beingboth spatial and temporal. The own time of relief has twovarieties: (1) evolutional or genetic rows of the relief's formswhich example by the geographical cycle (this is the Davis'stime, according to the analogy with the Newton's time or theLeibniz's time); (2) the morphological sequence which is the partof the common spatial-temporal structure of relief and isanalogous to the stratigraphical sequence of geologicalstructure.

The geological and the own time of relief have differentfunctional purpose in geomorphological investigations. Thegeological time of relief - is its period of existence. Themorphological sequence and the Davis's time - is the structuraltime of relief.

Institute of the Earth's Crust of the Siberian Branch of the

Russian Academy of Sciences, Irkutsk, Russia

5o

LUMINESCENCE DATING OF SEDIMENTS - LIMITATIONS AND PERSPECTIVES

ZOLLER, L.

During the past decade, TL dating of eolian sediments hasdeveloped to a reliable method. This is based on the fact thatlong bleaching by sunlight is able to reset the "clock" toa level close to zero, which can be reproduced in the laboratory.If the illumination during transport and deposition of a mineralgrain was not sufficiently long and intensive ("partial bleach"),TL ages be overestimated. This is often the case for severalfluvial and lacustrine sediments. Special "partial bleach"methods have been suggested to date those sediments, but theresults still remain questionable in some cases, e.g.the Holoceneflood-loams from smaller rivers. Sediments transported bysolifluction, mud-flows, turbidity currents and similarspontanous mass movements cannot be dated by TL.

Great experience exists in some TL laboratories for datingof loess and dune sand, but also raised beaches have been datedsuccessfully. Meanwhile eolian sediments can be dated reliablywithin their typical error bars of 10-15% in the range betweena few and about 100 ka. Thus, the TL method is able to date theentire last glacial-interglacial cycle. The upper limit is stillunder discussion. It depends on the material, the grain size andmineral fractions, and the laboratory technique. TL ages from thefine-grain (4-11 pm) fraction of loess, older than the lastinterglacial, are more or less underestimated, if compared toages derived from the tuned oxygene isotope chronology. Those TLages have to be regarded as minimum ages. According to ourexperiences from numerous loess sections in Middle and EasternEurope it seems possible, however, to establish a relative loesschronology as far back as the penultimate interglacial.

The upper limit of TL dating of eolian sand has not yet beenestablished unambiguously, but reliable ages as old as some 500ka seem possible under certain circumstances, especially fromsediments with very low natural radioactivity.

Consequently, cycles of geomorphological activity reflectedby deposition of eolian sediments can be reliably dated as farback as 100 ka, in some cases even further back. The timeresolution can normally not be much better than about 10% of theage. Examples from the European loess belt and the subtropicaldesert belt will be presented.

The newly emerging optical dating techniques (OpticallyStimlulated Luminescence, OSL) look more promising for reliabledating of partialy bleached sediments. Error bars and upper agelimits are in the same order of magnitude as for TL dating, butespecially for young (e.g. Late Glacial-Holocene) sedimentssystematical errors due to partial bleaching are supposed to bemuch smaller.

Forschungsstelle Archaometrie der Heidelberger Akademie der

Wissenschaften, FRG

51

Abstracts of Papers. International Symposium on Time, Frequencyand Dating in Geomorphology, Tatranski Lounica - Star Lesn&,June 16-21, 1992

Published, printed and copyright by the Institute of Geography ofthe Slovak Academy of Sciences, Bratislava 1992Editor: Milot StankovianskyTechnical Editor: JAn PravdaArtwork: JAn LacikaComputer Programming: tubomir SolinEdition of 110 copies