gibert et al 1999 - plio-pleistocene deposits of the orce region (se spain) geology and age

8/6/2019 GIBERT Et Al 1999 - Plio-Pleistocene Deposits of the Orce Region (SE Spain) Geology and Age

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Plio-Pleistocene deposits of the Orce region (SE Spain):Geology and Age

1 ' 3 1J111S GIBERT, 2 Eudal MAESTRO,3jOsep GIBERT, 1 ' 3 S ilvi a ALBADALEJO

'Dept. Enginyeria Minera i Recursos Naturals, Unversitat Politcnica de Catalunya.Escola Universitaria. Politcnica,Av. Bases de Manresa, 61-73, 08240 Manresa, Barcelona, Spain.'Una. Estratigrafia, Dept. Geologa,Universitat Autnoma de Barcelona,08193 Bellaterra, Barcelona, SpainFax: 935811263'Institut de Paleontologa M.CrusafontCarrer Escola Industrial 23,08201 Sabadell, SpainFax: 93727664.

ABSTRACT

A >100 m thick sedimentary succession comprising part of the Baza formation outcrops in the North Eastof the Guadix-Baza basin (South East Spain). New stratigraphical, biostratigraphical and palaeomagnetic datashow that the sedimentation in this area was almost continuous between the Middle Pliocene and the LatePleistocene. The Plio-Pleistocene sediments of this part of the Guadix-Baza basin forro a minimum of fiveunconformity-bounded depositional cycles. These cycles begin with fluvial sediments and finish with lacustrinerocks. The deposition of each sediment type depends on the position of the lake level, which in turns dependsmainly on the prevailing climate. These depositional cycles could be related to the global glacio-eustatic cycles.Each cycle contains a different fossil mammal faunal group. The new chronostratigraphic framework indicatesthat the paleontological sites with evidence of hurnan presence can be placed on the Plio-Pleistocene boundary.

1. INTRODUCTION

It is difficult to find large outcrops of continental sedimentary sequences in Europe which span Al the Plio-Pleistocene period.This is due in part to the glacial action during the Quaternary that has eroded and redepositedthe Plio-Pleistocene deposits. The remaining deposits are mainly from the Late Pleistocene and are attributed tothe last glacial and interglacial period. They mainly consist of fluviatile deposits, glacial lake sediments, loessdeposits and moraines. The Guadix-Baza basin (South East of Spain) offers a large continental sedimentarysuccession of this period, that can help us to improve the knowledge about the Plio-Pleistocene geologicalhistory. One of the important facts of this region is the presence of about 50 paleontological sites with fossilmanimals some of them with fossil human remains and lithic artefacts (Gibert et al. 1989 a, b, c, 1992, Tixieret al. 1995, Roe 1995). This article presents for the first time a detailed chronostratigraphical framework for theregion using new stratigraphical data supported by paleontological and paleomagnetic data and provides evidencefor Plio-Pleistocene palaeoclimate.

2. GENERAL SETTING

The studied area is situated in the SE of the Iberian Peninsula (fig.1), approximately at 120 km NE fromGranada, between the villages of Orce, Galera and Cullar (fig. 2). This region is actually a large depression risedapproximately 1000 ni aboye the sea level. It has a semiarid climate with an annual rainfall of 300-500 mm. Themountains of the Betic Chain that surround the depression reach 3000 m in height. These enviromentalconditions allowed the dominance of erosion processes, which have formed deep ravines where it is easy toobserve the sedimentary successions. This basin (cited as GBB from here on) is located in a nearly subtropicallatitude. The climate during the glacial periods was temperate.12 7


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The Betic Cordillera is situated in the western part of the Mediterranean Alpine System. It is comprisesof two major structural domains (Internal and External Zones) which consist of Paleozoic to Middle Miocenerocks, strongly affected by tectonic processes. During the Late Miocene (Tortonian) it began a neotectonic stage,with a great volume of compressive and distensive structures (Estvez and Sanz de Galdeano, 1983). Thistectonism created a great number of isolated sedimentary basins, marine or continental, depending on the ageand the position in the Chain. Prior to this "isolated stage" (Lower-Middle Miocene), these basins formed partof the Northbetic Strait, which representa the marine communication between the Mediterranean sea and theAtlantic ocean, north of the emerged lands of the Internal and External Zones of the Betic Chain. The GBBis the biggest of the Neogene-Quaternary hinterland basins of the Betic Cordillera (fig.1). During the LateMiocene the GBB become isolated from the others Betic basins (Vera 1969; Rodriguez Fernandez 1982;Rodriguez Fernandez et al. 1984). From the terminal Miocene (Turolian) to recent the GBB becomes conti-nental (Cuevas et al., 1984).The sediments that fill the GBB during the Plio-Pleistocene are mainly fluviatile in the SW and lacustrinein the NE. At the begining of the late Pleistocene (approximately 100.000 y.a) the last lacustrine deposits weredeposited. Inmediately after the region was uplifted and the current fluvial systeni was establish (Vera et al 1994).The whole of the Neogene to Quaternary sediments in the central arcas of the GBB reaches >1000 m (Vera1969, Santiesteban 1968).

The studied area, in the Northeastern sector of the GBB, expones deposits of Pliocene and Pleistocene age.They consist of marginal lacustrine and fluviatile sediments. This part of the GBB was occupied by a shallowlake (Vera, 1969) during this time. The lake, with an approximate surface of 1000 km 2 (Anadn et al 1986), hadits central area near Benamaurel village.The stratigraphical, sedimentological and petrographical data indicate that the lake was shallow, with a well-developed palustrine fringe. In this kind of lake, a small fall in the water-level table would produce the expositionof an extensive area (several km') covered by carbonate muds, and affected by the pedological processes. In thecentral arcas of the lake (Benamaurel zone), the depth that the lake reached was enough to permit a permanentwater body, even during falls of base-level. The stratigraphic record in these arcas consists only of subaqueouslacustrine facies.The physical characteristics of the paleolake allow the study and precise correlation of the depositionalcycles related to base-level fluctuations, especially in the marginal zones of the lake. The depositional cyclesconsist of a basal fluvio-alluvial unit, deposited in periods of low water-level, covered extensively, with lacustrinedeposits, which reflect the high water-level periods.

3. FACIES ASSOCIATIONSIn this sector of the GBB it is possible to distinguish different sedimentary facies associations related tofluvio-lacustrine depositional systems.These facies characterise different sedimentary environments and are distributedin function of the paleogeographical evolution of this arca during the Plio-Pleistocene.3.1 Fluvio-Alluvial Facies:

Flood plain: this type of facies has an important presence in all the Northeast margin of the basin andespecially towards the Northeast and the South of the studied zone (Orce, Fuentenueva and Cullar sector). Thesefacies have a typically red colour and comprise lutites. On occasion diagenetic gypsum is present in thesedeposits.Fluvial Channel facies: it is possible to identify two types of channels, which are geographically separated.In the South of this sector of the basin, flood-dominated braided channels that have Betic a source and flowinto the paleolake toward the West-Northwest are developed. In the Northeast (Orce-Venta Micena sector)meandering channels that come from the Northeast and continue towards the East are present.Alluvial Fans: These consist of conglomerate layers, deposited mainly by debris flows in periods of flooding.These facies are located in the most marginal zone and deposited by stationary channels. Towards the lake thesefacies interfinger with lacustrine rocks.Deltaic facies: the fluvial channels can form deltas when they reach the lake. These deposits are mainlyformed by wide layers of sand, which show thickening and coarsening up cycles. Occasionally the alluvial fansform small fan deltas (often Gilbert type) when they reach the lake shoreline.

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3.2Lacustrine Facies:

Palustrine area: These facies always appear in the most marginal zone of the basin. They are characterisedby the presence of dark beds which contain lignite. These levels have different sizes of grains (clay to mediumsand). It is very common to find root remains, gastropods and mammal fossils in all of them. The majority ofthe sites which contain micromammal fossils are in this type of deposit. These beds are very useful for localcorrelation.

Carbonate lacustrine fringe: These facies are characterised by the presence of pedogenically modified limestone.These are situated in the littoral zone of the paleolake, where there were frequent oscillations of the water level.The materials that constitute these facies are lacustrine limestones which frequently contains gastropod andostracod remains and evidente of subaerial exposure (edaphica structures, desiccation tracks, brecciation, collapsebrecciation and others).

Central lacustrine zone: we attribute these facies to the large deposits formed by alternating fine detritalmaterials and chemical sediments (mainly gypsun) which consist of continuous thin layers. These deposits aresituated in the SW of the studied area (towards Benamauruel).

4. CHRONOLOGYThe dating of the deposits has been made by paleomagnetic and biostratigraphic criteria. Four paleomagneticsections have been made. The longest section (>100 ni.) was studied by Garces near Galera village (Garces 1993,

1994, Agust et al 1997). He found Tour clear normal events, which he identified as Gauss (three) and Olduvai.Semh (1985) and Agust ct al (1997) found one normal event in the Orce ravine (near Orce village) whichis interpreted by the Olduvai normal period (Agust et al. 1987, Gibert et al. 1993, Agust et al. 1997).Finally Oms et al (1995) found a probable normal event in the Fuentenueva section which is attributed tothe Olduvai period (Gibert et al 1993, Oms et al 1995). This last paleomagnetic section has not been consideredin our study because the data are unclear due to low magnetic susceptibility of the materials (Oms com pers.).The beds with mammal fossils are very frequent in this sector of the GGB. After studying the stratigraphicsituation of the sites, it is possible to establish five levels with different mammal fossils between the middlePliocene and the late Pleistocene. This supposes five large faunal breaks.Agust (1986) and Agust et al (1987) made a proposition for the Lower Pleistocene biozonation withoutstratigraphical location of the sites. Today it is possible to say that this proposition is no longer valid, becausethere are important contradictions with the stratigraphical data (Gibert, J. et al 1993, Gibert, J. et al 1995).

5. PLIO-PLEISTOCENE DEPOSITIONAL CYCLES

5.1 Introduction

Our analysis of the deposits is based on their cyclicity.The basic data are correlation fences, biostratigraphicaland paleomagnetic data. The basin of this work is the measurement of 35 detailed stratigraphic sections (fig.3).The basin was filled by lacustrine sediments during periods of expansion of the lacustrine system and fluvio-alluvial sediments in periods of paleolake regression. These alternating sedimentary environments correspond tothe cycles of the paleolake base level. The cycles are bounded by unconformities near the borders of the basin,and tend to be conformable in the centre. These unconformity-bounded units are depositional sequences (sensu

Vail ct al. 1977, 1987,Vail et al. 1991,Van Wagoner et al. 1990). The cycles boundaries have a chronostratigraphicalsense.Until now five depositional cycles have been recognised within the Plio-Pleistocene of this region. Eachcycle comprises fluvial sediments in the base and lacustrine deposits at the top.This new sequential interpretationis substantially different from other mainly lithostratigraphic interpretations, made during the last fourteen years(Vera ct al. 1984, Anadon et al. 1986, Soria ct al. 1987 and Garces 1993) (fig.4). These five major cycles areformed by minor-order cycles that are made during high-frequency base-level oscillations. These minor cyclesare represented in the margin of the basin as a succession of paleosols.

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5.2 Depositional cycles

5.2.1 Galera Cycle

Lacustrine member: the studied area exposes only the top lacustrine sediments of this cycle. They correspondto highstand deposits (sensu Uliana and Legarreta 1988). This member is the lowest stratigraphic unit thatoutcrops in the studied area. The beds consist of limestones, calcareous mudstones, marls, and clay with peattowards the top. These sediments are slightly deformed probably by diapirism. One of these beds containsRuscinian midromammal fossils, that outcrops in the site Galera-1 (Agust 1986) or Nuca-1 (Ruiz Bustos 1991a).These materials outcrop mainly in the bottom of the valley of the Orce river between the villages of Orce andGalera.

5.2.2 Fuentenueva CycleFluvial member: a unit of red fluvial materials, that consists of sand, lutites and conglomerates, was unconformallydeposited aboye the Middle Pliocene lacustrine member (Vera ct al 1984, Soria 1987). These beds are thickerthan 10 ni. Those deposits come from the Eastern part of the basin and develop the fluvial facies towards theWest supplying the sediments to the lake restricted to the central area of the basin. This fluvial member is veryuseful in regional correlations because it continues for more than 14 km in an E-W direction. No paleontologicalsites have been found in these sediments. The paleomagnetic data of this member (Garces 1993, 1994, Agust

et al 1997) occurs in the top of the Gauss normal event.Lacustrine member: this unit is developed over the precedeing fluvial member. It comprises white limestones,marls and calcilutites. This member is no thicker than 10 m. in the most marginal zone (Fuentenueva), butincreases in thickness towards the West (Galera village).Within these sediments the Villafranchian paleontologicalsite Fuente-nueva-1 (Moya-Sol et al 1987) is located.5.2.3 V enta Micena CycleThis cycle starts with the record of a smaller fall in the water level than the second cycle. At the beginningof the second cycle the shoreline moved back farther than Galera village (more than 14 kni to the W). In thiscycle the shoreline retreated no more than 10 kni to the W. Because of this the facies exposed m the Orce sector(East) are different from the Galera sector (West) where the subaqueous conditions persist, and the fluvial

sediments became deltaic. Anadon ct al., 1986 studied the palaeosalinity of the lake in this member using faunalchanges (ostracods, mollusca and foraminifera) and indicate an alternation of slightly salive and bicarbonato-richwater with a salive NaCl-dominant water.Fluvial member: this member (fig.5) is formed by red lutites, with sand and conglomerate intercalations.This red unit representa flood plain facies in the South of the Orce region (near Sierra de Orce) and meanderingchannel facies towards the North. The paleoflows indicators show that the meandering fluvial system carne fromthe NE. Occasionally diagenetic gypsum crystals appear inside this unit. The conglomerates are componed of

Jurassic cobbles, flint and quartz.Lacustrine member: comprise the units which were described by Gibert et al 1993.Green unit: this unit is made of green marl sediment, which has root traces. The mineralogical composition

for it is 20% quartz and 60% carbonates. The thickness is no more than 5m and we interpret it as a transitionalenvironment between lacustrine and fluviatile.First carbonate unt: aboye the green member a lacustrine limestone unit rich in micritic calcite (CaCO3>95%)is developed. This unit is affected by edaphic structures produced during the frequent oscillations in the water

level of the lake.Black detrital uns: It has a variable thickness between 3 m and 0.4 rn. It is formed of dark beds that arerich in organic matter and gastropods. Inside this member a large amount of mammal fossils sites (B. Len, B.Paso, C. Alfonso, B. Conejos, Fuentenueva-2, Venta Micena-1) are present associated with the botton of theOlduvai paleomagnetic event (Semh 1984, Agust 1987, Gibert et al 1993, Agust et al 1997). Three of thesepalaeontological sites (B. Len, B. Paso and C. Alfonso) are rich in stone artefacts (fig.6) which indicated humanactivity in this depression during the Plio-Pleistocene boundary (fig.7), (Gibert et al. 1992, Tixier et al 1995,Zihlman and Lowenstein 1996, Gore 1997). We attribute this member to sediments deposited in a marshenvironment. The size of the grains is often lutite (


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center of the lake these deposits evolve to mud flats with less organic matter and increasing carbonate content.The general trend is a flat and shallow lake with more detrital supply. In the most marginal outcrops grain sizeincreases to sand. We attribute this to the filter effect produced by the marsh environment.Second carbonate unit: This carbonate member is thicker and more complex than the first. It implies atransgression of the lake. The composition of this unit is mainly carbonate (>95% CaCO 3 ). At the base of thismember the Venta Micena Level occcurs which contains a large accumulation of mammal fossils including humanremains (Gibert et al. 1989a, 1989b, 1989c, 1992, 1995, 1998, Campillo 1989, Campillo and Gibert 1996, Borja

et al 1992, Borja 1995, Lowestein 1995, Zihlman and Lowenstein 1996) and the site Fuentenueva-3 where morethan 100 stone artefacts have been found in association with a large collection of mammal fossils (Tixier et al.1995, Gibert et al 1992, 1998). Part of this unit is placed incide the Olduvai event (Agusti et al 1997) (fig. 3,fig. 8). The paleomagnetic and biostratigraphyc data are in disagreement with those published by Torres et al(1997) who chronologically situate the base of this unit (Venta Micena bed) around a million years (983 58Ky) using amino acid racemization analysis.The facies of this unit are similar to the first carbonate unit. In the marginal areas of the basin (B. Len)some flood-dominated lacustrine deltas are developed, and interfinger with lacustrine limestones (Fig.7). Betweenthe Venta Micena Level and the top of the second carbonate unit coarsening upward lacustrine sequences occurswhich could indicate a tectonic pulsation. This member ends with a limestone bed, about one metre thick whichis rich in gastropod remains and forms a large structural surface.

5.2.4 Cullar-1 CycleAt the end of the Lower Pleistocene a displacement of the lake depocenter towards the South began. Asa consequence of this desplacement and a reduction of the subsidence rate in the NE of the studied area, thethickness of this cycle decreases towards the NE. This complete cycle outcrops in the South of the studied area(Cullar sector) while in the North (Orce-Galera) only the lowstand materials (fluvial) appear.Between the Venta Micena and Cullar-1 cycles there is a change in the paleoflow indicators in the Northof the studied area (Orce-Galera). While in cycle Venta Micena the fluvial systems carne from the NE, in cycleCullar-1 the fluvial systems carne from to South. This is reflected by a change in the source area of the detritalsediments, which change their carbonate composition (cycle Venta Micena, Subbetic source) to a metamorphic

composition in cycle Cullar-1 (Betic source).Fluvial member: this member is situated at the top of the sections in the Orce-Galera sector. It isrepresented as a detrital body that consists of metamorphic sands and cobbles. This unit is formed mainly bychannel deposits. The paleoflow indicators show that the fluvial systems carne from the South. Towards the Norththey develop to sands with wave ripples associated with a deltaic enviroment.In the NE of the studied area (Fuentenueva sector) this member is formed by the deposits of small alluvialfans and fan deltas coming from Subbetic source area (Sierra de Orce).Towards the South (Cullar sector) this unit reaches its thickest part and the colour becomes a deeper red.Lacustrine member: this member outcrops extensively at the South of the studied area (Cullar). In the Northit has only been recognized in the West of the Orce Village. It becomes thicker towards the South. It consistsof fine carbonatic detrital sediments. Cullar Baza-1 site is located within this unit. This site contains MiddlePleistocene mammals in association with stone artefacts (Ruiz Bustos, 1984).5.2.5 Cycle Cullar-2This cycle has been recognized in the South of the studied area. Due to posterior erosion this cycle is poorlyexposed.Fluvial member: Aboye the Middle Pleistocene lacustrine unit a fluvial member was deposited. The sourcearea is the same as the preceding fluvial member (Sierra de las Estancias, Betic source) and consequently iscomposed of metamorphic grains. The thickness of this member is about 8 ni.Lacustrine member: aboye the final fluvial deposits, a white member is exposed. This last unit consists offine detrital lacustrine limestones with some intercalations of sands with grains of metamorphic composition.This member is situated at the top of the sedimentary succession and has been mainly eroded out.Inside these materials the paleontological site Cullar-2 is located (Alberdi and Ruiz Bustos 1989) which hasan Upper Pleistocene horse (Equus caballus sp). Probably this member could be correlated with the Late Pleistocenesite (Vera 1984) called "Solana del Zamborino" that is situated out of the study area and within similar sediments.

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6. PALAEOSOLS

Palaeosols are very common in the lacustrine marginal deposits.They are proof of the continuous fluctuationsof the lake level, and represent the lowstand of high-frequency cycles. These paleosols are hypercalcimorphs (90-99% CaCo 3 ), and show different pedological features (brecciation, root traces, root tubules, microkarst,pseudomicrokarst, laminar trust, planar and curved voids, calcareous nodules and desiccation tracks) (fig.9). Thedegree of soil development is not the sane in all of them. The well-developed paleosols have a large lateralcontinuity, and are useful in local correlations around the lake margin.

On occasion a great concentration of mammal fossil, bones appear aboye the surface of these paleosols. Thiscan be recognized in the cite Venta Micena where more than 15000 fossil bones have been found in 200 ni2.

7. PALEOCLIMATIC IMPLICATIONS

7.1 Geological indicators:

Every depositional cycle described begins with a important fall in the base level. This could be caused byconsequence of intense tectonic activity or paleoclimatic changes, or both. In the studied area we have recognizedtectonic activity after Galera cycle where a clear unconformity occurs and at the top ofVenta Micena cycle whereminor fluvial beds and others lacustrine showing important increase of grain size appear. This last event coincideswith a change in the source areas and with a migration of the sedimentation areas. The following tectonic eventappear during the Upper Pleistocene where all the depresion is uplifted and the basin comes exorheic.We concluded that only in two of the five cycles described tectonic could be caused a fall in the lake level,althought if paleontological, isotopical and global climate evolution is consider (see below) it is possible to saythat the big falls in water level could be related mainly to climatic changes, although tectonic activity producessmall oscilations of the relativo base level. The large fluvial members described could correspond to dry periodsand the lacustrine sediments to warmer with higher humidity periods.

7.2 Palaeontological indicators:Every depositional cycle coincides with an important mammal break (fig.10). Inside the fluvial sedimentsthat correspond to lowstands in the lake and we attribute to dry and cold weather, no paleontological sites havebeen recognized. In the materials that correspond to highstand (lacustrine members) all the paleontological sites

with mammal fossils appear, and each group of fossils is different for each cycle. It has been concluded that fluvialperiods is a propicious period for mammals renovation (extinctions, migrations and species evolution) that couldbe related to dry and cold enviroments.The oxygen isotopic studies using horse tooth and bone fossil phosphates (Sanchez Chillon et al 1994)indicate a warm climate for the lacustrine members of Fuentenueva,Venta Micena, Cullar-1 and Cullar-2 cycles.These data are in agreement with our hypothesis. On the other hand, Ruiz Bustos (1991b and 1993) havecorrelated, using micromammal analysis, the deposits of the GBB with the Northern Europe Quaternary deposits(Alpine sequence), interpreting each lacustrine member of the GBB as an interglacial period.7.3 Relationships with the eustatic curve:Haq et al. 1988 established four third-order eustatic cycles from 3 to 0.5 m.y. The speed and intensity bywhich these cycles have been made and their correlation with paleoclimatic data indicate that these eustaticoscilations are related to global paleoclimate changes (glaciations), which also affected the continental depositional

environments.The cycles TB3.7, TB3.8, TB3.9 began respectively at 3, 2.4, 1.6. Considering the palaeomagnetic data(Agust et al 1997) these ages correspond to the fluvial members found in the studied area for cycles 2, 3, 4.This would imply that the global falls in the sea level were in phase with fans in the lake level.This hypothesis strengthens the idea that in general, the fluvial sediments of the studied area, are relatedto dry and cold climate during periods of low base level. The marginal lacustrine carbonates, correspond to

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8. DISCUSSIONThe sector Galera-Venta Micena is not dificult to correlate. hecause the Orce river which fiows parallel atSierra de Orce (marginal zone) cuts the stratigraphic succession along ah the way. The different geomorphology

of the Galera-Cullar sector presents more difficulries for its correlation. In chis part of the marginal zone thetop of the section has been mainly eroded and there are no outcroops of the complete sedimentary succession.With this situation it is difacult to be sure if the last lacustrine member defined in Galera sector (Marchal),corresponda with the midle Pleistocene lacustrine member of Cullar. It is possible that this member wouldcorespond with the lowest lacustrine member defined in R. Nlaciacerrea. If this other interpretation could beconfirmed from new paleontological sites discovered and carry out more stratigraphical and paleomagneticsections, it would imply that another, not defined depositional cycle would exist in this area between the lowerPleistocene and the midle Pleistocene.

9. CO NCLUSIO NSIn the studied area it is possible to establish high resolution time fines using stratigraphic sequential

criteria. It permits correlation between distant points with a high degree of precision. Five depositional cycles have been recognised inside the studied area. Each cycle begins with fluvialsediments and fmish with lacustrine.These cycles are a consequence of falls in the basinal base level produced mainly by the alternation ofdry weather periods and others with more humid.The physical characteristics of the depositional environment that existed in this area during the Plio-Pleistocene have permitted the formation of an extraordinary number of sites with mammal fossil deposits. The large continuity in the sedimentation of the Guadix-Baza basin during the Plio-Pleistocene is anexceptional fact. It may be possible, in the near future to establish a new mammal biozonation for this periodof time in Europe.If the data of Agust et. al. 1997 are correct, the paleoanthropological sites The paleoanthropologicalsites placed inside the Black Detrital Unit (B. Len, B. Paso and C. Alfonso) are chronologically situated nearthe base of the Olduvai event, this means that this sites have an age of near two millions years, being the oldestsites with evidences of human presence outside Africa.ACKOWLEDGMENTS:

The discussions with A. Ruiz-Bustos about the biostratigraphy and geology are gratefully acknowledged.Thanks to Dr. E Plana who made the mineralogical analisis and to K. Kupczik for helping with the translation.This paper has been supported by the project D.G.I.C.Y.T PB94-1222-0O2-01 of the Spanish Ministry ofEducation and Science.

REFERENCES

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Los restos Humanos de Orce y Cueva Victoria. pp.:187-220. Institut Paleontologic M. Crusafont, Diputacide Barcelona.CAMPILLO, D. and GIBERT, J. (1996). El Hombre de Orce. Investigacin y Ciencia, Marzo 1996.pp.: 64-69.CUEVAS, E; MARTIN-PENELA, A.; RODRIGUEZ-FERNANDEZ, J.; SANZ DE GALDEANO, C. andVERA, J.A. (1984). Premiere datation du Turolien la base de la Formation de Guadix. Geobios 17: 355-361.ESTVEZ, A. and SANZ DE GALDEANO, C. (1983). Notectonique du secteur central des Chines Btiques(Basins de Guadix-Baza et de Grenade). Rey. Gol. Dyn. Gegr. Phys., 24: 23-24.GARCES, M. (1993). Magnetoestratigrafa de los sedimentos lacustres Pliocenos de la seccin de Galera. Tesis delicenciatura, Universidad de Barcelona, Spain.GARCES, M. (1994). Magnetoestratigrafia de los sedimentos lacustres Pliocenos de la seccin de Galera (Cuencade Guadix-Baza, Cordilleras Bticas). Acta Geolgica Hispnica, Vol. 29: 191-194.GIBERT, J.; RIBOT, E; FERRANDEZ, C.; MARTINEZ, B; RUZ, C. (1989a). Anatomical study: comparisonof the cranial fragment from Venta Micena (Orce, Spain) with fossil and extant mammals. Human

Evolution, 4: 283-305.GIBERT, J.: RIBOT, E; FERRANDEZ, F.; MARTINEZ, B.; CAPORICCI, R. (1989b). Caractersticas dife-renciales entre el fragmento de craneo de Horno sp. de Venta Micena (Orce, Granada) y los quidos.Estudios Geolgicos, 45: 121-138.GIBERT, J.; CAMPILLO, D.; GARCA-OLIVARES, E. (eds), (1989c). Los Restos Humanos de Orce y CuevaVictoria, Institut Paleontologic M. Crusafont.GIBERT, J. (Coordinador) (1992). Presencia Humana en el Pleistoceno inferior de Granada y Murcia. Museo dePreistoria Josep Gibert, Orce, Granada.GIBERT, J.; ARRIBAS, A.; MARTNEZ, B.; ALBALADEJO, S.; GAETE, R.; GIBERT, L.; OMS, O.; PEASC.; TORRICO, R. (1993). Biostratigraphie et magnetostratigraphie des gisements presence humaine etaction anthropique du Pleistocene inferieur de la rgion d'Orce (Grenade,Espagne). Comptes RendusAcadmie des Sciences de Paris, t. 318. Pars.GIBERT, J.; GIBERT, L.; ALBALADEJO, S. (1995). Biostratigrafia de la regin de Orce. Nuevos datos. ResumenesI Congreso Internacional de Paleontologa Humana, Orce 1995.GIBERT, L.; MAESTRO, E.; GIBERT, J.; ALBALADEJO, S. (1997). Depositional cycles in the Orce region(Guadix-Baza SE Spain) and their relation with Plio-Pleistocene climatic changes. Colloque Hispano-Franais: Milieux Carbonates Continentaux. Etudes de Gographie Phisique, supplment au n XXVI: 15-16 .GIBERT, J.; GIBERT, LL.; IGLESIAS, A.; MAESTRO, E. (1998). Two Oldowan asemblages in the Plio-Pleistocenc deposits of the Guadix-Baza basin (SE Spain), Antiquity, vol 72.GIBERT, J.; CAMPILLO, D.; ARQUES, J.M.; GARCIA OLIVARES, E.; BORJA, C. and LOWENSTEIN J.(1998). Hominid status of the Orce cranial fragment reasserted. Journal of Human Evolution, vol. 32: 203-217.GORE, R. (1997). The first Europeans. National Geographic. vol. 192, no. 1, July 1997.HAQ, B.U.; HARDEBOL, J. and VAIL, P. (1988). Mesozoic and Cenozoic Chonostratigraphy and EustaticCycles. In: Sea-Level changes an integrare aproach. C.K. Wilgus, B.S Hastings, C.G. Wagoner (eds.) Soc.Econ. Paleont. Mineral., Spec. Pub. 42: 71-108.MOYA SOLA, S.; AGUST, J.; MARIN, M. (1987). Fuentenueva-1: nueva localidad con mamferos del Pliocenosuperior de Guadix-Baza (Granada,Spain). Paleont. i Evol. Mem. sp. 1: 287-295.OMS, O.; PARES, J.M.; AGUST, J. (1995). Resmenes Congreso Internacional de Paleontologa Humana. Orce,Granada (Spain).OMS, O.; DINARES, J. y PARES, J.M. (1996). Resultados paleomagnticos iniciales de la seccin Plio-Pleistocena de Fuente Nueva (Cuenca de Guadix-Baza, Cordilleras Bticas). Rey. Soc. Geol. Espaa, 9:1-2.

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ROE, D.A. (1995). The Orce basin (Andaluca, Spain) and the initial Palaeolithic of Europe, Oxford JournalArchaeology 14: 1-12.RODRIGUEZ-FERNANDEZ, J. (1982). El Mioceno del sector central de la Cordillera Btica. Tesis Doctoral,Universidad de Granada.RODRIGUEZ-FERNANDEZ, J.; MARTINEZ DEL OLMO, W.; GARRIDO MEGIAS, A.; VERA J.A. (1984).Paralelismo entre algunas formaciones que colmatan el Mediterraneo Espaol y la depresin de Guadix-Baza (Cordilleras Bticas). Primer Congreso Espaol de Geologa, Segovia, 3: 173-182.RUIZ BUSTOS, A. & MICHAIUX, J. (1976). Le cite prehistorique nouveau de Cullar Baza 1 (province deGrenade, Espagne) d'ge plestocene moyen. Etude preliminaire et analyses de la faune des rongeurs.Geologie Medterrane, 3: 173-182.RUIZ BUSTOS, A. (1984). El yacimiento paleontolgico de Cullar Baza-1. Investigacin y ciencia, 91.RUIZ BUSTOS, A. (1991a). Biostratigrafia de los sedimentos negenos del sector de Galera. I Congreso GrupoEspaol del Terciario. Vic, pp.: 301-304.RUIZ BUSTOS, A.(1991b). Biostratigraphy of the continental Neogene in the Betic Cordilleras. Terra ahstracts,vol. 3, n. 1. VI meeting European Union of Geosciences.RUIZ BUSTOS, A. (1993)11e Quaternary framework in the Betic Cordillera and its correlation with theNortherm Hemisphere. Resurnenes III Reunin del Quaternario Iberco, Coimbra.SNCHEZ CHILLN, B.; ALBERDI, M.T.; LEONE, G.; BONADONNA, E P.; STENNI, B.; LONGINELLIA. (1994). Oxigen isotopic compositin of fossil equid tooth. and bone phosphate: and archive of difficultinterpretation. Paleogeography, Paleoclimatology, Paleoecology, n 107: 317-328.SANZ DE GALDEANO, C. and VERA, J.A. (1992). Stratigraphic record and paleogeographical contex of theNeogene basins in the Betic Cordillera, Spain. Basin Research, n 4, pags: 21-26.SANTIESTEBAN, E. (1968). Investigaciones hidrogeolgicas por el mtodo elctrico en Baza (Granada), Bol.Geol. Min. t. 79, fase. 2: 75-81.SMAH, F. (1985). Analyses palomagntiques dans la depresson de Guadix-Baza (Grenade, Espagne). Unpublished.Inst. Paleontologia "M.Crusafont".SES, C, (1989). Micromamferos del Mioceno, Plioceno y Pleistoceno de la cuenca de Guadix-Baza (Granada).Geologa y paleontologa de la Cuenca de Guadix-Baza (Alberdi M.T and Bonadonna EP. eds) Trabajos sobreel Neogeno-Cuaternario, Museo Nacional de Ciencias Naturales. Madrid.

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Atlantic Ocean Mediterranean

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Neogene-Quaternary

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PLIOPLEISTOCE NE DEPOSITS O F THE ORCE REGION (SE SPAIN) : GEOLOGY AND AGE

Figure 1: Geological map of the SE of the Iberia Peninsula, which show the geological location of the Guadix-Baza basin

Figure 2: View of the NE sector of the Guadix-Baza basin showing the studied area and the location of somepaleontological cites: Venta Micena, Fuentenueva (FN), Barranco del Paso (BP), Barranco Len (BL), Barrancode Orce (BO), Galeral(G1), Molino (MO), Cullar Baza 1 (CB1) and Cullar Baza 2 (CB2).13 7


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Figure 3: Correlation fence showing the cyclicity of thedeposits, the paleomagnetic sections published (Agust et al1997) and the location of paleontological sites in the Orceregion. The cycle's boundaries reflect high resolution timelimes which permit correlate with precision the palaeomagneticdata between distant points of the basin.

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Venta MicenaCycle

Fuentenueva

Galera Cycle

Garces1993Galera

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Vera et al.1984Orcemiembro

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FLUVIATILE TRANSITION LACUSTRINE

Soria et al. 1987Galera Orcealera Orce

PI 10-PLEISTOCENE DEPOSITS OF TI IE ORCE REGION (SE SPAIN): GEOLOGY AND AGE

Figure 4: Correlation of the depositional cycles described for the Orce and Galera sector with previous lithostratigraficunits.

Figure 5: View of the lacustrine member of Fuentenueva cycle (A) and the fluvial (B) and lacustrine (C)members of Venta Micena cycle in the Fuentenueva section. The arrow shows the location of the Fuentenueva1 palaeontological cite.139


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Figure 6:View of the Barranco Len site (arrow). This site has been excaved in summer of 1995, and more than100 stone artifacts were found surrounding an hippopotamus remains (fig. 7). The thickness of the sedimentaexposed are 60 m

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aNg/-'4 BL.5 Palustr ine sedimenta, 1- 4 (Black Detrital Unit11-4y

sh si vilinevemw p g

Shale wth root traces. gastrops, lignit, fosal] mammals and big mammal 1 ootprints at the top

Fine sand carbonate cementad. w th gastrops and small root tracesBrown very fine sand w th gastrops, root tracesSin w th ostracods and roca tracesVery fine sand wt h ostracods, gastrops and CerastodermaCarbonatic trust wth load casiSilt w th lignit, fossil mammals, gastrops and root traces

Silt w th gastrops and root traces at the top

Dark silt wth very fine a p arta grains, lignit, iron oxide, root traces and fossil mammalsCarhonatic sin wth root tracesVery f ine sand w ith intraclastes and root traces

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PLIOPLEISTOCENE DEPOSITS OF THE ORCE REGION (SE SPAIN): GEOLOGY AND AGE

B. Len sedimentary sequence1 , Glacis Detailed section of the Black Detrital Unit

111111~1I Very f ine sand wri th rippinSal anal rwylt and sorna mamad remainsSa Ion some kdraclasis and gastropsWwy f iro sand with organic masar showing'ery fine sand w th traction carpet lamnation

BL5 Z:11,17,%T." :117=7.1,1. `,217,12,r. ",11=:=1 1

Barranco Len 5 excavation planShal low I lacustr ine l imestones, withhipercalcimorphic paleosols

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Fluvialsedimento

7 6 5 4 3 2 1

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Figure 7: Barranco Len sedimentary sequence, showing the different facies that occur, the location of the B. Len-5site and the palaeomagnetic data associate infered from the correlation with Barranco de Orce palaeomagnetic section(fig,8). The figure shows too the excavation plan of B. Len-5 made in summer of 1995 indicating the distribution oflithic artefacts and of hippopotamus remains and the location of human remains.

141


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17/18

PLIOPLEISTOCENE DEPOSITS OF THE ORCE REGION (SESPAIN): GEOLOGY AND A.J.E

Figure 9:View ofhipercalcim orphicpalaeosols insidelacustrine mate-rials of Venta Mi-cena cycle.

A ,, STRATIGRAPHICSUCCESsioN MAMMALS GROUPS FOS S IL LOCALIT IES

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GIBERT, L.,MAESTRO, E., GIBERT, J. Y ALBADALEJO, S.

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Orceisotopicanalisis (1)EUSTATIC CURVES (2)

Om. -50 -1001AG EOm.y.

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LACUSTRINE DEPOSITS FLUVIATILE DEPOSITS

Figure 11: Orce sedimentary succession and the different groups of fauna associated for each depositional cycle.

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gibert et al 1999 - plio-pleistocene deposits of the orce region (se spain) geology and age

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