Author's personal copy - University of Minnesota et al... · aDepartment Enginyeria Minera i Recursos Naturals, Universitat Polite`cnica de Catalunya, Av. Bases de Manresa 61-73,

This article was published in an Elsevier journal. The attached copyis furnished to the author for non-commercial research and

education use, including for instruction at the author’s institution,sharing with colleagues and providing to institution administration.

Other uses, including reproduction and distribution, or selling orlicensing copies, or posting to personal, institutional or third party

websites are prohibited.

In most cases authors are permitted to post their version of thearticle (e.g. in Word or Tex form) to their personal website orinstitutional repository. Authors requiring further information

regarding Elsevier’s archiving and manuscript policies areencouraged to visit:

http://www.elsevier.com/copyright

http://www.elsevier.com/copyright

Author's personal copy

Quaternary Science Reviews 26 (2007) 2067–2089

The Early to Middle Pleistocene boundary in the Baza Basin (Spain)

L. Giberta,�, G. Scottb, R. Martinc, J. Gibertd

aDepartment Enginyeria Minera i Recursos Naturals, Universitat Politecnica de Catalunya, Av. Bases de Manresa 61-73, Manresa 08240, SpainbBerkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, USA

cDepartment of Biological Sciences, Murray State University, Murray, KY 42071, USAdInstitut de Paleontologıa ‘‘M.Crusafont’’, Escola Industrial 23, Sabadell 08201, Spain

Received 31 May 2006; received in revised form 2 May 2007; accepted 17 June 2007

Abstract

The continental vertebrate fauna of Cullar Baza-1 (Granada, Spain) occur immediately above the Matuyama/Brunhes polarity

boundary, and therefore represent an initial record for the Middle Pleistocene. All polarity zones for the Late Pliocene through Middle

Pleistocene are found in an 80m section, which includes this fossil quarry. The existing collection of abundant remains of micro-

mammals, macro-mammals and lithic artifacts (indicating human activity) can now be assigned an earliest Middle Pleistocene age of

0.75Ma. Another section, 25 km across the Neogene Baza Basin, also has the Matuyama/Brunhes polarity boundary. However, in this

case the Huescar-1 fossil quarry and the Puerto Lobo sites are both below the polarity boundary, thus representing a record of the late

Early Pleistocene at �0.9Ma. Differences in micro-mammal species across these Matuyama/Brunhes boundaries are significant and

justify an approximately coincident biostratigraphic boundary between the Biharian and Toringian stages.

r 2007 Elsevier Ltd. All rights reserved.

1. Introduction

The intra-montane Guadix-Baza Basin is the largest ofthe late Neogene inland basins of the Betic Cordillera. As aconsequence of the Alpine Orogeny, this Basin was isolatedfrom the sea during the late Miocene (Sanz de Galdeanoand Vera, 1992). The Basin had an internal drainage ofapproximately 4000 km2 and could be divided into twosub-basins. Generally, the Guadix Basin to the southwestwas filled with alluvial deposits, while lacustrine deposits,along with fluvial/alluvial marginal deposits (Fig. 1),dominated the Baza Basin to the northeast.

Six hundred meters of late Neogene continental sedi-mentary infilling is exposed in the marginal northeasternpart of the Baza Basin (Gibert L, 2006). Gravity andseismic studies indicate 42500m of lacustrine sedimentsburied near the town of Baza (Alfaro et al., in press). Thepaleo-environments within the Baza Basin included ashallow saline lake complex, surrounded by saline mud-flats, freshwater ponds, small rivers with floodplains anddeltas (Gibert L. et al., 2005, 2007). The grass-covered

upland slopes merged into alluvial fans from the surround-ing mountains. The Baza Basin continued accumulatingsediment until tectonic movements and stream piracyinitiated rapid and prolonged erosion (Calvache andViseras, 1997), stripping the softer, upper strata andleaving behind the more resistant layers that make up thepresent-day topography.The Baza Basin has produced 440 fossil vertebrate sites

of Late Miocene, Pliocene and Pleistocene age, alongwith some lithic artifact sites of Pleistocene age showing theactivity of early man (Ruiz-Bustos, 1976, 1984; Gibert J.et al., 1998, 2006). Magnetostratigraphic studies from thenortheastern part of the Basin (Gibert L. et al., 2006;Scott et al., 2007) have generated a polarity sequencefor the Orce-Venta Micena sections (three magnetozones,reverse–normal–reverse) revealing the Pliocene/Pleistoceneboundary and calibration of the MN17 (mammalNeogene zone) upper boundary. The youngest depositsin these sections are of Early Pleistocene age (pre-Jaramillochron or 41.1Ma), bounded by an upper erosionsurface at 965masl. Other areas in the Basin have suppliedfossils that indicate younger fauna than in the Orce-VentaMicena area; these are Puerto Lobo-Huescar and Cullar,the focus of this report. Both of these younger areas have

ARTICLE IN PRESS

0277-3791/$ - see front matter r 2007 Elsevier Ltd. All rights reserved.

doi:10.1016/j.quascirev.2007.06.012

�Corresponding author. Tel.: +34937472423.

E-mail address: [email protected] (L. Gibert).


well-exposed sedimentary sections, interbedded with fossi-liferous sites and thus are well suited for detailedmagnetostratigraphic research. This study furthers ourgeneral goal of developing a wider and more completechronologic and biostratigraphic framework for the BazaBasin. All geologic observations in this report are theproduct of the authors, unless specifically referred.

2. The Cullar section

In 1975, Cullar Baza-1 (CB-1) was the initial paleonto-logical excavation in the Baza Basin, which now includesnumerous archeological/paleontological quarries, mostlyconcentrated in the Orce area, 20 km to the NE (e.g. VentaMicena, Fuente Nueva-3). An early Middle Pleistocene agewas assigned to CB-1 using faunal criteria (Ruiz-Bustosand Michaux, 1976; Ruiz-Bustos, 1984).

A preliminary magnetostratigraphic and paleontologicstudy was made �2 km NW from the CB-1 quarry (UTM30537120E, 4159537N, Z ¼ 890–905; Fig. 2) (Agustı et al.,1999). Situated �50m stratigraphically below the CB-1level, that study consisted of a 14m section with 10paleomagnetic and three paleontologic levels. The Cullarsection in this current report is meant to supersede andexpand these preliminary observations. We will emphasizethe following advantages: (A) an additional 70m ofoverlying strata were sampled; (B) the paleontological

quarry CB-1 was included within the new section; (C) mostof the samples from the new collection have high-qualityremanent polarities (mostly reddish-brown siltstones andpaleosols); and (D) field tests were conducted to indicatethe stability and antiquity of remanence. By incorporatingthe results from the preliminary section (Agustı et al., 1999)into this expanded section, the following features wererevealed: (1) the paleontological site CU-A will not beconsidered further, since it has only a sparse collection ofpost-cranial bones, as none were originally reported(Agustı et al., 1999); (2) the upper 4m of that preliminarysection are not part of the Baza Formation, but areunconsolidated or poorly consolidated claystones, sand-stones and conglomerates composed of intra-basin clastsand discontinuous calcrete beds that belong to the muchyounger post-erosional, valley in-fill deposits; and (3) thepaleontological site CU-C, within these post-Baza deposits,is Late Pleistocene or latest Middle Pleistocene, as are theuppermost three normal polarity samples in the prelimi-nary report. Our observations indicate that these youngpost-Baza Formation deposits are extensively preservedalong the flanks of the present Cullar River Valley and aresignificantly younger than the erosive opening of the Basin(Fig. 3).In the present study, a magnetostratigraphic section was

developed 2 km SE of the town of Cullar. This sectionstarts near the Cullar River (UTM coordinates:

ARTICLE IN PRESS

Fig. 1. Location maps. The Baza Basin (SE Iberian peninsula) showing the stratigraphic sections and paleontological sites. 1—Cullar section and quarry

CB-1; 2—Puerto Lobo sections and sites; 3—Loma Quemada sites; 4—Huescar-3 site; 5—Sabinar section; 6—Orce sections and quarries FN-1, VM, BL-

5, and FN-3; 7—Oria road section.

L. Gibert et al. / Quaternary Science Reviews 26 (2007) 2067–20892068


ARTICLE IN PRESS

Fig. 2. Aerial photos. The Cullar (top) and Puerto Lobo (bottom) areas, showing the primary and ancillary magnetostratigraphic sections as dashed lines.

L. Gibert et al. / Quaternary Science Reviews 26 (2007) 2067–2089 2069


30539063E, 4159055N, Z ¼ 900), follows the Oria roadand then the side valley towards the CB-1 quarry(30538659E, 4158276N, Z ¼ 966) until the top of thevalley (30538709E, 4158186N, Z ¼ 975). The upper 5mof the section were collected in the next valley to thewest (30539182E, 4157813N, Z ¼ 985). The sectiontotals 81m in thickness, starting above Mesozoic carbo-nates, including the paleontological quarry CB-1 (Fig. 2),and ending with the uppermost strata below theerosive llano surface. This new section was made infresh outcrops or road cuts of alluvial fan and palustrinefacies. Paleomagnetic samples were taken from thefiner-grained units (primarily siltstones) between theconglomerate beds and lenses. Conglomeratic channelsprovided an opportunity to apply the conglomerate/tilt testto fine-grained blocks swept from the banks of the paleo-channels.

3. The Puerto Lobo section

The Puerto Lobo section was located in the northernmargin of the Baza Basin, 3 km SE of the town of Huescarand 25 km north from the Cullar section (Fig. 1). This areais adjacent to a far-ranging normal fault (Soria et al., 1987)with a minimum estimated displacement of 30m (direction049/70N). In a previous study of a subaqueous landslide ofEarly Pleistocene age, a few reverse polarity samples werecollected from the upthrown side of this fault (Gibert L. etal., 2005). On the downthrown side of the fault are thestratigraphically higher fossil sites of Puerto Lobo andHuescar-1, along with the new magnetostratigraphicsections (Fig. 2).The Puerto Lobo section (UTM coordinates 30543408E,

4182540N, Z ¼ 935–965; Fig. 2) starts in strata from thedistal fluvial facies (mudflats, overbank deposits) rich in

ARTICLE IN PRESS

Fig. 3. Photos of post-Baza Formation outcrops. Preliminary Cullar paleomagnetic section of Agustı et al. (1999) (line A–B) shows the disconformity and

samples within overlying (Upper Pleistocene) deposits. Photos: 1: general view with 14m sampled section and position of younger valley fill deposits

(between dashed lines). 2: location of three samples along road cut, the upper of these samples was collected above the disconformity (dashed line) and

shows normal polarity (Agustı et al., 1999). Note initial dip toward valley (left) in younger beds. 3: recent excavation (50m from section) showing

disconformity. 4: details at point ‘g’ in photo 2, showing unconsolidated conglomerate with subangular intra-basin clasts immediately below discontinuous

calcrete bed (top normal bed of preliminary section). Similar exposures are typical along both sides of the immediate Cullar valley.



metamorphic grains of southern provenance. North-directed paleocurrents dominate in this northeasternmargin of the Basin, where small local ponds haddeveloped. These deposits belong to the same lithostrati-graphic unit as those in the highest topographic positionacross the fault, in the upthrown block. The Puerto Lobo(PL) paleontological site (Agustı, 1984) is located in thetopographically lower (older) part of the down-faultedblock. Higher in the section there are palustrine deposits,capped by a continuous alluvial unit composed of cross-bedded gravels and siltstones with paleocurrents towardsthe SW. This uppermost unit shows a distinct change inclast composition and provenance (Mesozoic carbonatefrom the north and east) compared to the lower part of thesection (metamorphic grains from the southern moun-tains).

The site of Huescar-1 (HU-1) (UTM 30543727E,4183228N, Z ¼ 948) is located in the next valley (Barrancode Las Canadas), o1 km NE of PL (Fig. 2). There are twoother paleontological sites in these younger deposits of thedown-faulted block: Loma Quemada-1 and -2 (LQ-1, LQ-2), 2 kmW (30541848E, 4181276N, Z ¼ 900) (Soria et al.,1987). LQ-1 and LQ-2 have a micromammal fauna similarto that from PL (Agustı, 1984). The site of Huescar-3 (HU-3) (30543408E, 4182540N, Z ¼ 1000) is located close to thePL section, but is on the other side of the fault in theupthrown block. The HU-3 fauna are Pliocene in age (Sese,1989), thus much older than those from sites on the down-dropped side.

The Puerto Lobo and Barranco de Las Canadas areasexpose a variety of lithologies and show lateral changes inlocal facies. Wherever possible, we collected the reddish-brown siltstones for these preliminary magnetostrati-graphic sections. Good exposures allow for the integrationof biostratigraphic and paleomagnetic data into a litho-stratigraphic frame. These results offer an opportunity toidentify magnetozone boundaries and to make a distantcorrelation to the contemporaneous Cullar section. Pa-leontological sites with similar age but in different paleo-environmental and paleogeographical situations allow anexamination of faunal diversity (Alberdi et al., 2001), aswell as a more complete biostratigraphy.

4. Methods

Recent work in the Baza Basin provided a detailedlithostratigraphic frame for the NE sector, around Orce-Venta Micena, along with the magnetostratigraphic loca-tion of the Pliocene–Pleistocene boundary (Scott et al.,2007). This present study is an expansion both northwardsto Huescar and southwestwards to Cullar. Numerousstratigraphic sections have been measured in and betweenthese three areas, permitting some insight into thecomplexity of deposition facies and the paleo-topographicrelationships across this part of the Baza Basin. Thesedifferent paleo-geographical situations show lateral litho-logic changes, ranging from the coarse-grained facies

typical of paleo-margins to the fine-grained sulfate-dominated facies around the central paleo-lake. Althougha detailed lithostratigraphic correlation between these threemarginal sites remains ellusive, the addition of magneto-zones greatly improves the temporal correspondence.

4.1. Sampling methodology

We chose the most propitious sections in the two areasto study. These sections have three characteristics: (1)abundant reddish-brown, fine-grained lithologies for pa-leomagnetic sampling; (2) ease of correlation to othernearby sections; and (3) close to or including paleontolo-gical sites to calibrate the polarity sequence. In 2003, wecollected preliminary samples (n ¼ 11) from both sections(Cullar and Puerto Lobo). This provided an outline of thepolarity zonation and an indication of the magneticbehavior of the different lithologic types. Additionalsamples were collected in 2004 (n ¼ 16), expanding thesections. In 2005, we made more detailed collections(n ¼ 41) extending the sections and refining the positionof each magnetozone boundary.In the Cullar section, we tested the continuity of the

uppermost magnetozone boundary (R to N) by collectingsamples in stratigraphically equivalent beds along the Oriaroad (n ¼ 5) (UTM 30559593E, 4158301N, Z ¼ 970)(Fig. 2). We also collected samples (n ¼ 4) from aboulder-sized tilted block, broken from the wall of apaleo-channel (Fig. 5). The orientation of the remanentmagnetic vector in strata within this rotated block wouldbe a specific test for the antiquity of remanence. This fieldtest would indicate which magnetic components wereproduced at an early diagenetic stage and which componentswere produced after the bank collapsed into the paleo-channel. At Puerto Lobo the upper part of the sectionshowed weakly held remanence and ambiguous polarities, sowe resampled (n ¼ 6) equivalent strata in reddish-brownlithologies (taking advantage of a local facies change) atBarranco de Las Canadas (just above the site HU-1) (Fig. 2).

4.2. Paleomagnetism

We collected block samples (Cullar n ¼ 55, Puerto Lobon ¼ 13) directly through the sections, in shallow excava-tions made by hand, and in road cuts. From each orientedblock, at least three specimen cubes (10–15 cm3) were cutand sanded (without water), then cleaned with compressedair. Measurements were made at the Berkeley Geochronol-ogy Center with a three-axis cryogenic magnetometer(noise level 1� 10�12Am2) enclosed within a room-sizedmagnetostatic shield (average field 350 nT). Alternatingfield (AF) demagnetization (static three-axis, to at least12mT) was followed by thermal demagnetization (in atleast eight steps) starting at 90 1C (non-inductive furnace,residual field o2 nT). Polarity results exclude two unstablesamples at Cullar and three at Puerto Lobo. In general, thequality of the remanence recorded was excellent for the

ARTICLE IN PRESSL. Gibert et al. / Quaternary Science Reviews 26 (2007) 2067–2089 2071


common light reddish-brown siltstones/claystones (93% ofsamples) or was poor for the light gray mudstones,sandstones and carbonates (7% of samples). All specimenshave a two-component magnetization (Fig. 4) made up of alow-coercivity/low-temperature component (toward themodern field direction) and a higher temperature compo-nent (in the normal or reverse direction). Variable ratiosbetween the modern and ancient remanence componentsare the cause for the variations in demagnetization

response (Fig. 4). The modern field component waseffectively reduced by AF treatment followed by heatingto 200 1C (0001/531, a95 ¼ 2.81, n ¼ 45; goethite only:000 1/531, a95 ¼ 2.31, n ¼ 44).A few samples displayed a more complex magnetization,

with higher temperature components showing both normaland reverse polarity. These samples were adjacent tomagnetozone boundaries, apparently reflecting an integra-tion of ambient magnetic fields and events. This was most

ARTICLE IN PRESS

Fig. 4. Paleomagnetic specimen data from Cullar section. Orthogonal demagnetization diagrams (vector endpoints during demagnetization) are shown for

specimens from normal (left) and reverse (right) strata. Horizontal projects are shown as triangles, vertical projection as circles, and NRM (4mT) starting

point as asterisks. Magnetization is in units of A/m. The 200 1C demagnetization step delimits modern (normal) from ancient (normal or reverse)

remanence. Directional changes also shown as stereographic projections (circle is horizontal plane) with solid (open) symbols on lower (upper) hemisphere.



noticeable in a sample (+28m) within the middle normalzone. As a test this block was cut into 17 specimens (assmall as 2 cm3), producing five normal (012/54, a95 ¼ 8.91),five reverse (206/�56, a95 ¼ 21.31) and seven intermediateresults. These detailed specimens spanned only 7 cmvertically; however, the polarities were irregularly distrib-uted in three dimensions. Since this sample was of typicallithology (siltstone with immature paleosol textures), weassume that the ambient field changed polarity during thepedogenic alteration process affecting this bed.

Sample directions were calculated both from furthestposition along great circle trends (shown) and from least-squared line-fit of vector endpoints. The line-fit results weresimilar to the great circle trends (75% have o101difference), although slightly less consistent and usually(68%) closer to the modern field. The stratigraphicsequences of paleomagnetic directions are displayed asthe angular difference (D) between a specimen direction (S)and the expected normal direction (N) (Hoffman, 1984).This plot directly reflects the multiple component nature ofthese vector data. Calculations of VGP latitudes wouldyield the same polarity zonation, but are not shown as anexplicit caution against interpreting minor directionalvariations as geomagnetic phenomenon.

4.3. Paleontology

4.3.1. Introduction

In the absence of radiometric dates, rodent biochronol-ogy is helpful for temporal calibration of a polaritysequence. Below, we briefly review the history of rodentbiostratigraphy in the Cullar and Puerto Lobo regions andcomment on taxonomic issues. In later sections we discuss

the specimens in detail and then interpret their biostrati-graphic significance.For a variety of reasons, some biological and some

probably related to collecting bias, most of the Guadix-Baza micromammal samples are dominated by arvicolidrodents. Fortunately, the diversity of arvicolid species inthe Basin, combined with their rapid speciation throughoutthe holarctic region during the late Neogene, makes theirremains useful for correlation purposes. Nevertheless, thereis considerable disagreement on fossil arvicolid taxonomyamong European investigators. It is beyond this treatmentto summarize all the pertinent literature. A more compre-hensive review will be published elsewhere. At this point,we choose to treat most European ‘‘Microtus-like’’ speciesas members of the genus Microtus, with a commonMimomys ancestor. Thus Allophaiomys, Stenocranius,

Iberomys, Terricola, etc. are considered subgenera ofMicrotus. Also, following van der Meulen (1978), we donot recognize the subgenus Pitymys in Europe. This nameis reserved for the North American M. (Pitymys) pinetorum

and its relatives, although its ancestor, M. cumberlandensis,apparently immigrated back into North America from Asiaduring the Middle Pleistocene (van der Meulen, 1978).Fossil relatives may eventually crop up in the Old World.For many years Arvicola has been considered to represent agenus separate from Microtus, evolved from the extinctMimomys savini. However, a new paradigm of Arvicola

evolution has been proposed (Ruiz-Bustos, 1999) suggest-ing that Arvicola and Microtus share a common Mimomys

ancestor, with M. savini as a separate sterile Mimomys

lineage. In either case, the progression of evolution in thefirst lower molar (m1) of European Arvicola has beenextensively documented (e.g., Heinrich, 1990; Ruiz-Bustos,

ARTICLE IN PRESS

Fig. 5. Field test. Road cut showing channel of conglomerate in the lower Cullar section, with an enclosed ‘tilted block’ (notebook for scale). Four

paleomagnetic samples from block are shown schematically (sample CU05-31 is of normal polarity). Wall rocks, outside of channel are of the same

lithology (siltstone) as in the ‘tilted block’.



1999; Maul et al., 2000), and the morphology of Arvicola

molars can be valuable for correlation purposes. Forinstance, Spanish populations of fossil Arvicola withrelatively small molars and negative enamel differentiationcan be assumed to be older than ones of larger size andnegative differentiation or with positive differentiation(Ruiz-Bustos, 1999). Likewise, rootless Microtus m1sdemonstrate many features that have both taxonomicand evolutionary meaning, including complexity of pattern(number and form of triangles) and enamel differentiation.However, there are a number of named species in westernEurope with overlapping m1 morphologies, and withsparse fossil material it is often difficult or impossible tomake a satisfactory species identification. For example,there are at least five ‘‘Allophaiomys-type’’ species with m1morphology that are somewhat advanced over ‘‘typical’’Microtus (Allophaiomys) pliocaenicus from the typelocality of Betfia, Romania (Kormos, 1930; Hir, 1998)including M. ruffoi (Pasa, 1947), M. burgondiae (Chaline,1972), M. nutiensis (Chaline, 1972), M. chalinei (Alcaldeet al., 1981), M. vandermeuleni (Agustı, 1991), and M.

lavocati (Laplana and Cuenca-Bescos, 2000). We agreewith Ruiz-Bustos (1999) that M. chalinei, originallydescribed from Cueva Victoria in south-eastern Spain(and also identified from Atapuerca in north-westernSpain; Cuenca-Bescos et al., 2001), is an Arvicola, thoughits dental complexity excludes it from ancestry of modernA. terrestris or A. sapidus. Microtus vandermeuleni wasrecently allocated to the genus Tibericola (Unay et al.,2001; Agustı and Madurell, 2005).

Ruiz-Bustos and Michaux (1976) first reported arvicolidrodents from the Cullar Baza-1 (CB-1) locality. Agustı(1986) proposed a rodent biochronology for the early andmiddle Pleistocene, including new material from thelocalities near Cullar (CU-A, B, C) assigned to the UpperBiharian. Localities near Huescar (HU-2, LQ-1 and PL)were assigned to the Middle Biharian European landmammal age (ELMA), older than the Cullar Baza andCullar localities. Sese (1989) reviewed much of the rodentmaterial from the Guadix-Baza Basin, and reportedspecimens from HU-1. The age suggested for HU-1 was‘‘middle Pleistocene’’, while PL and LQ were ‘‘lowerPleistocene’’, and CB-1 was Biharian. An attempt tocorrelate paleontological localities in the Cullar area withthe geomagnetic polarity time scale (Agustı et al., 1999)placed CB-1 in the Toringian ELMA with CU-A, B and Cbeneath, in the Biharian. A normal polarity zone at thelevel of CU-C was assumed to be from the earliest Brunhes(based on geologic observations described in this currentreport, site CU-C is out of stratigraphic context and is nowassigned to the late Brunhes). CU-A and -B, in sedimentsof reversed polarity, were placed just below the Brunhes inchron C1r.1r (this current report changes the assignment toan older chron: C1r.2r). These latter localities wereallocated to the Biharian. An arvicolid rodent biochronol-ogy for the Guadix-Baza area was proposed (Agustı et al.,1999), with Arvicola cantinaus representing the Toringian

(following Fejfar et al., 1998) and three superposedBiharian zones, from youngest to oldest Terricola

arvalidens, Allophaiomys burgondiae and Allophaiomys

pliocaenicus. They confirmed the earlier placement of CB-1 in the Toringian, but did not refer to localities in theHuescar area. A new biostratigraphic scheme was pro-posed for the Orce region in a recent comment paperby Agustı et al. (2007), but the utilization of paleontolo-gical sites located in landslide zones (O-2, O-3; Gibert L.et al., 2006, 2007) and post-erosional deposits (Cu-C)to build this biostratigraphy makes it of questionablevalue.

4.3.2. Methods

We reviewed the existing collection of rodents from theCullar and Huescar areas housed at the PaleontologicalInstitute of Sabadell, along with some specimens providedby Ruiz-Bustos. Two sets of sites bear on calibration of thepolarity sequence in the Cullar area: Cullar Baza-1, CU-A,-B, -C. CB-1 produced numerous macro- and microfaunaremains (Ruiz-Bustos, 1976) while Agustı (1984) andAgustı et al. (1999) described a few rodents from theseCullar sites. Four paleontological sites are known from theHuescar area: HU-1, HU-3, Puerto Lobo and LomaQuemada (Agustı, 1984; Sese, 1989). HU-1 has produceda large collection of macrofauna with some species ofmicrovertebrates (Sese, 1989). Puerto Lobo and LomaQuemada have produced only microvertebrates (Sese,1989; Agustı and Madurell, 2005). HU-3 is located 300mSE from HU-1 and is topographically 50m higher but hasproduced a Late Pliocene (Ruscinian) macro- and micro-fauna (Sese, 1989). This is explained by the presence of anormal fault between these sites (Soria et al., 1987). Thespecimens from HU-1 and -3 are not located in theInstitute of Paleontology in Sabadell. For these siteswe will rely entirely on the published faunal account(Sese, 1989). Other records in the database include bothreferences from the literature and our independent assess-ment of material examined in the Institute of Paleontologyin Sabadell.

5. Results

5.1. New paleomagnetic data

Two new polarity sequences are now available in theBaza Basin: Cullar (81m) in the southwest and PuertoLobo (31m) in the northeast. The extensively sampledCullar section has six major magnetozones: a 1.5m reversezone in the lowest strata, followed by a 7.5m normal zone,then a 24m reverse zone, a short normal zone of 2.5m,another long reverse zone (25.5m), and at the top, a 19mnormal magnetozone (Figs. 6 and 7). Near the base of theuppermost normal zone is the paleontological/archaeolo-gical site CB-1 with abundant mammalian remains andlithic tools indicating human activity (Fig. 8). Near thebase of the lower long reverse polarity zone would be

ARTICLE IN PRESSL. Gibert et al. / Quaternary Science Reviews 26 (2007) 2067–20892074


the projected stratigraphic level of site CU-B (using thecorrelation of Agustı et al., 1999). A very short normalzone (o10 cm) was found 3m above the lowest normalzone. This cryptozone was inadvertently discovered in the

tilted block used for the conglomerate/tilt stability test.A short (o50 cm) magnetozone, this time with reversepolarity, was found within the 2.5m middle normalmagnetozone.

ARTICLE IN PRESS

Fig. 6. Magnetostratigraphic data for Cullar section. Remanence directions, intensity and low-field susceptibility in relation to stratigraphic position are

shown, with means (open circles) and specimens (solid circles, 3 each). Lithostratigraphic column is shown with position of fossil quarry (bone symbol),

samples (arrows) and samples from ancillary section (C) along Oria road.



ARTICLE IN PRESS

Fig. 7. Cullar section correlated with GPTS. Geomagnetic polarity time scale (after Gradstein et al., 2004) is shown with correspondence to Cullar

polarity zones, D (calculated from Dec. and Inc.) and lithostratigraphy. Cos (D) ¼ sin (Inc N)�sin (Inc S)+cos (Inc N)�cos (Inc S)�cos (Dec N-Dec S)

(N ¼ 0001, 571; S ¼ specimen direction).



The more sparsely sampled Puerto Lobo sections havetwo magnetozones: a 18m reverse zone, followed by a 13mnormal polarity magnetozone (Fig. 9). This lower reversezone includes the sites of PL, LQ-1, LQ-2 and HU-1, withtheir large collection of micro- and macro-fauna. Nofossiliferous sites have been described from the uppernormal zone; however, we identified lithic artefacts in theconglomeratic gravel bed that caps this section.

5.2. Magnetochronology

Both studied sections present an almost continuoussedimentary sequence typical of the marginal facies of anunderfilled basin. No evidence of extensive sedimentaryhiatuses have been identified, with missing time restrictedto levels with immature paleosols and local erosionalsurfaces. Some features common to these Baza sectionsargue for relatively complete sequences (after McMillanet al., 2002): high sedimentation rates (�10 cm/kyr) and thelarge number of strata. This kind of sedimentary recordfacilitates the correlation of the identified polarity zoneswith the GPTS (Geomagnetic Polarity Time Scale, afterGradstein et al., 2004). Using the paleontological data as ageneral age guide, as well as other tested polarity sequencesin the Basin (summarized by Scott et al., 2007), these new

polarity zones can be correlated to the Pliocene-Pleistocenepart of the GPTS.For the Cullar section we correlate the lowest normal

zone to the Olduvai magnetochron (C2n), and the under-lying reverse zone to the end of the early Matuyama(C2r.1r). The normal polarity zone in the middle of thesection would then correlate to the Jaramillo subchron(C1r.1n). The upper (19m) normal zone, starting justbelow site CB-1, would correlate to the Brunhes magne-tochron (C1n). A very thin normal zone (o10 cm, tilttested) identified 3m above the lowest normal zone couldbe the Gilsa subchron (C1r.2r.5n, after Channell et al.,2002). The other short zone, a reverse within the middlenormal zone is interpreted as C1r.1n.1r (see Guo et al.,2002). Other possible correlations have significant flaws. Ifthe long upper normal zone corresponds to the Jaramillosubchron, then the fauna of CB-1 would be 1.0–1.1Ma,which is probably too old. If the lowest normal zonecorresponds to the Jaramillo subchron (therefore, themiddle normal to the Santa Rosa (C1r.1r.1n) (Singer andBrown, 2002) or the Kamikatsura subchron (Coe et al.,2004)), then sediment accumulation would have begun latein this area, and then proceed very rapidly (425 cm/kyr).This would require the paleo-Cullar Valley/Fan to changefrom a paleo-topographic high to a paleo-topographic low.

ARTICLE IN PRESS

Fig. 8. Lithic artifacts. Flint lithic tools from CB-1 quarry (1987 collection, after Vega Toscano, 1989).



ARTICLE IN PRESS

Fig. 9. Magnetostratigraphic data, GPTS correlation- Puerto Lobo sections. Magnetic information, lithostratigraphy and correlation to GPTS for the

Puerto Lobo sections have the same conventions as in Figs. 6 and 7.



This younger model is unsupported by the observed stablemid-fan deposition environment draining westward intothe nearby paleo-Lake Baza with its distinct, but stablesubenvironments (Gibert et al., 2007).

For the less densely sampled Puerto Lobo sections, wecorrelate the upper (13m) normal magnetozone to theBrunhes chron (C1n). This is guided by the youthfulness ofthe faunal assemblage from sites HU-1 and PL. Wediscount the other possibility of correlating the normalmagnetozone to the Jaramillo subchron, as this wouldmake these faunas 1.2–1.3Ma. This is probably too old, asthe HU-1 and PL micromammals appear distinctly young-er that those from the Orce-Venta Micena area (Fuente-nueva-3, Barranco Leon-5) which are of this older age(Scott et al., 2007).

These new results disagree with some previouslypublished chronologies for the sites CB-1 or Hu-1, datedusing biochronological methods (Hernandez Fernandez etal., 2004) and for those dated using the amino-acidracemization techniques (Torres et al., 1997; Ortız et al.,2000, 2004).

5.3. Tests for antiquity of remanence

5.3.1. ‘‘Tilt block’’ test

Different components of magnetization can be acquiredduring different events in a sample’s history. A continuingchallenge in magnetostratigraphic research is to determinewhich, if any, of the remanent components were acquiredat the time of deposition, or at least early in the process oflithification-diagenesis. To examine the antiquity of rema-nence, the fold and conglomerate tests were developed byGraham (1949). These tests take advantage of unusualgeologic situations where changes have occurred in theorientation and/or position of newly deposited strata.Some examples are: rip-up clasts, intra-formational con-glomerates, bioturbation and slumps. These events physi-cally rotate the young rock, along with any remanentdirection that was already stably magnetized. If the rockhad not acquired a stable remanence before rotation, itwould now have that opportunity, but in a new orienta-tion. These types of tests allow a comparison of theremanent directions (both measured and expected) at thetime of deposition and after the time of change. The shorterthe duration between deposition and rotation, the morestringent the temporal constraints will be for the acquisi-tion of remanent components.

In the Cullar section, we found a situation where amigrating paleo-channel cut into a newly deposited over-bank deposit, causing blocks to cave off the paleo-channelwall. These fallen blocks were then rotated and incorpo-rated into the conglomeratic channel deposit. A boulder-sized tilted block (60� 40 cm) was found within the paleo-channel, and used for a conglomerate or ‘‘tilted block’’ test.The block (Fig. 5) has a rectangular shape and is composedof reddish-brown sandstone and siltstone (bedding: strike2851, dip 601N). The block’s original stratigraphic position

can be recognized in the parent sediment located in theadjacent walls of the paleo-channel. Four samples (sixspecimens) were collected from this block, spanning 30 cmof tilted strata.Tilted samples show stable magnetic components at

about 901 from the expected paleo-field directions (0001/+571 or 1801/�571). These components are also distinctfrom those in samples collected from in-situ strata backfrom the channel walls. However, after correcting for thebedding within the block, the sample directions havereverse inclinations (�701, in block coordinates) for threelevels and an approximately antipodal normal inclination(+601) for the other level (Fig. 11). Using these limiteddata, we can identify some additional features, since non-antipodal paleomagnetic directions can be sensitive in-dicators to the presence of secondary magnetization (Scottand Hotes, 1996). Fig. 11 shows that the great circlethrough these tilted bi-polar data includes the modern fielddirection (within 71). This was unexpected, since reversepolarity was the ambient field direction both before and fora long time after the channel-forming event. This meansthat among the secondary components, the reverse post-depositional magnetizations (either pre- or post-tilting)were not as important as the younger (modern) normalcomponent. Apparently, the processes of near-surfacealteration (weathering in the modern normal field)dominate the secondary magnetization in these tiltedsamples. A similarly directed, modern secondary compo-nent is common in the data from most in-situ samplesthrough out the Cullar section. The magnitude of thissecondary component can be calculated at �20% (relativeto the pre-tilting remanence intensity at 2001) using themethodology in Scott and Hotes (1996). These techniquesalso calculate an original average inclination of 651 forthese tilted samples (Fig. 11). Considering the limitednumber of samples in this test, this successfully approx-imates the expected mean inclination of 571.The observations from this ‘tilted block’ field-test

produce four conclusions: (1) Much of the naturalremanent magnetization (NRM) was acquired at an earlystage of diagenesis and lithification. (2) No significantambient (reverse field) component of remanence wasacquired after the block broke loose and was incorporatedin the paleo-channel deposit. (3) A pre-tilting normalzone (o10 cm thick) of short duration was found. Thepresence of this very thin subzone within the tiltedblock is another indication of rapid and early NRMacquisition. (4) Laboratory demagnetization techniques(AF followed by thermal) can greatly reduce the secondarymagnetizations in samples, but can still leave a 20%residual component directed toward the modern (normal)field.

5.3.2. Stratigraphic continuity tests

Changes in paleomagnetic polarity should be indepen-dent of lithologic changes, and should be reproducable andcontinuous between outcrops. To check the continuity of



ARTICLE IN PRESS

Fig. 10. Detailed maps and cross-section profiles. Digital relief maps show the location of fossil sites and cross-sections. Topographic profiles have

geologic cross-sections, with polarity, paleo-current directions, and paleo-environments indicated. The Cullar profile (A-B-C) shows the 6 polarity zones

through 81m of section. The superseded results of Agustı et al. (1999) are 2 kmW and 50m below the CB-1 quarry. Their normal samples are in post-Baza

Formation deposits from the current episode of erosion. The Puerto Lobo-Barranco de las Canadas section (A-B) shows an upper zone of ambiguous

polarity in PL (diagonal lines), which upon re-sampling 600m to the north in B. Canadas, was found to be a normal magnetozone.



the upper magnetozone boundary in the Cullar section, wecollected five additional samples along the Oria road, 1 kmeast of the primary Cullar section. Samples were fromstratigraphically equivalent beds; however, fewer palustrinestrata were present owing to a facies change (moving upthe paleo-slope from the ancient Lake Baza). Thechange from reverse to normal magnetozone was foundin light brown and reddish-brown siltstones on both sidesof the boundary (Figs. 6 and 12). A less specific test forcontinuity of magnetozones across facies involves thecorrespondence between part of the Cullar section’s middle(24m) reverse zone (reddish-brown siltstones) and the(10m) reverse zone fragment (Agustı et al., 1999) 2 kmnorth-west, in more distal, gray mudstones and yellowsandstones. In our initial Puerto Lobo section, samples(gray sandstones) above the continuous reverse magneto-zone had scattered directions (ambiguous polarity). Thus,we collected six samples from equivalent upper strati-graphic levels, o1 km north-east in Barranco de LasCanadas (above the site HU-1). These additional sampleswere from reddish-brown siltstones, and indicate a long(13m) normal polarity magnetozone (Figs. 9, 10), includ-ing the uppermost exposures intercalated with cross-bedded conglomerate.

5.4. Biostratigraphy

Strata from the Cullar area were used in an initialattempt to calibrate the Early to Middle Pleistoceneboundary by Agustı et al. (1999). Our stratigraphicobservations and paleomagnetic results differ significantlyfrom theirs, and therefore influence the biostratigraphicevaluations. Paleontologic and biostratigraphic modifica-tions are noted below. We found one m1 referred toTerricola arvalidens from CU-C and another m1 ofCastillomys crusafonti from CU-B in the collections ofthe Paleontology Institute in Sabadell. Both were figuredby Agustı et al. (1999). However, we did not find anyspecimens of Stenocranius gregaloides from the Cu-C site asreported by Agustı et al. (2007). As indicated by thecrenulated anteroconid in the drawing (Agustı et al., 1999;Fig. 3.1), the ‘‘Terricola’’ m1 from Cu-C is from a juvenileindividual. The area of the crenulations was broken offwhen we recently viewed it, but the specimen is otherwiseintact. No identifiable molars were found in the collectionsfrom CU-A and none were reported (Agustı et al., 1999).Castillomys crusafonti was reported from four stratigraphichorizons, spanning 70m (Agustı, 1986; Agustı et al., 1987;Garces et al., 1997) in the Galera Highway section (15 km

ARTICLE IN PRESS

Fig. 11. Antiquity of remanence field test. Paleomagnetic results from the tilt-block shown in Fig. 5 (4 sampled levels, 6 specimens total). Directions in the

present or in-situ coordinate frame are shown on the left, showing the bedding plane within the block (strike 2851, dip 601N). The nearly antipodal

directions are grouped at 0381, �321 (5 specimens, 3 stratigraphic levels), and at 2261, +541 (1 specimen, 1 stratigraphic level). The ambient (post-tilting)

normal and reverse paleo-field directions are shown as triangles (0001, +571; 1801, �571). Directions in the ancient bedding coordinate frame are on the

right, showing the bedding plane within the block as horizontal (although N is not paleo-north). The concentric circle at 571 inclination (+ or �),

represents expected values. Note that the reverse polarity group (1181, �701, a95 ¼ 8.61, k ¼ 100.3) and the normal sample (3411, 571) are not exactly

antipodal. Also, the great-circle connecting these bi-polar data passes close to the modern field direction (diamond), which is the common secondary

direction in other Cullar results). Non-antipodal paleomagnetic directions provide the following parameters: a ¼ 631, b ¼ 111, g ¼ 231, s ¼ 0.22 (using

methods in Scott and Hotes, 1996). These calculations indicate 22% of the demagnetized remanence is still held by a secondary component in the direction

of the modern field.


Author's personal copyARTIC

LEIN

PRES

S

Fig. 12. Correlation panel for Cullar, Orce and Huescar sectors. Lithostratigraphic and magnetostratigraphic correlations between 3 areas with paleontological sites: CB-1 (Cullar Baza-1), FN-1

(Fuentenueva-1), VM (Venta Micena), BL-5 (Barranco Leon-5), FN-3 (Fuentenueva-3), PL (Puerto Lobo) and HU-1 (Huescar-1). The correlation Cullar to Orce is based on the C2n (Olduvai) polarity

zone. The correlation Orce to Huescar is based on linking a sequence of 9 lithostratigraphic sections (Gibert L, 2006). The offset on the Puerto Lobo fault (minimum shown) is based on matching clast

provenance. The correlation Puerto Lobo to Barranco de las Canadas is based on physically following key beds.

L.

Gib

ertet

al.

/Q

ua

terna

ryS

cience

Review

s2

6(

20

07

)2

06

7–

20

89

2082


northeast of Cullar). This long-lived species is of little valuefor zonal calibration purposes at this stratigraphic level.

As noted above, we found a stratigraphic disconnectbetween localities CU-B and CU-C with a 70m hiatusbetween. The site CU-C and the deposits that produced thepurported Terricola arvalidens molar occur in post-erosional basin sediments (not in the Baza Formation);therefore, the CU-C fossils must be considerably youngerthan those from CB-1. This produces a correlationalproblem, as M. arvalidens fossils from elsewhere in Europeoccur earlier than Arvicola cantianus and Microtus

brecciensis, the species from CB-1 (Table 1). The anatomyof the broken arvicolid m1 from CU-C is similar to somem1 morphotypes from Microtus (Terricola) arvalidens, butit can also be duplicated in modern pine vole species,including the extant M. duodecemcostatus from Spain(Brunet-Lecomte, 1988). Closure of buccal reentrant angle(BRA) 3 and lingual reentrant angle (LRA) 4, modestpenetration of BRA 4 and LRA 5 forming incipient butdistinct T6-7 in the anteroconid, plus the distinct positiveenamel differentiation, identify the molar piece as from anadvanced species of Microtus. The overall pattern, withT4-5 confluent certainly suggests the subgenus Terricola.

Brunet-Lecomte (1988; Fig. 16) also showed that arelatively simple morphology of m1, as demonstrated bythe CU-C specimen, can change with age (wear) into amore complex molar in modern pine voles. We interpretthe arvicolid specimen from CU-C as a Late Pleistocene orsub-Recent specimen of M. duodecemcostatus or anotherrelated, morphologically advanced species. Therefore, the‘‘Terricola arvalidens’’ zone of Agustı et al. (1999) is notconfirmed in the Cullar sections. We do not know whatarvicolids existed directly below the Brunhes-Matuyamaboundary at Cullar, although we can speculate based onthe rodents from Puerto Lobo and Huescar-1.The arvicolid species from Puerto Lobo and Huescar-1

(Sese, 1989), including Mimomys savini (both localities) andMicrotus huescarensis (HU-1), are consistent with a lateBiharian date, in agreement with Fejfar et al. (1998) andAgustı et al. (1999). Both species were reported by Cuenca-Bescos et al. (1999) from Trinchera Dolina at Atapuerca, insediments of reversed polarity directly beneath theBrunhes-Matuyama boundary. To date, Arvicola cantianus

( ¼ A. mosbachensis of Maul et al., 2000) has not beenrecorded from the Matuyama chron. In fact, this speciesdoes not seem to appear anywhere in Europe until about

ARTICLE IN PRESS

Table 1

Faunal list

Compilation made for selected micro-mammals (rodents) and large mammals from Pleistocene paleontological sites in the Baza Basin and in northern

Spain (Atapuerca). Data compiled from Mazo et al. (1985), Alberdi et al. (1989), Garcıa and Arsuaga (1999), van der Made (1999), Gibert J et al. (2001,

2002), van der Made and Mazo (2001), and Scott et al. (2007).



0.60Ma (Maul et al., 2000). Although an archaeologicaland mammal assemblage with Arvicola cantianus wasinitially reported from sediments older than 0.73Ma atIserna la Pineta (Coltorti et al., 1982), new dates place thisassociation at about 0.61Ma (Coltorti et al., 2005).

The paleontological sites located in the area of study canbe sequenced from older to younger (Figs. 12 and 13;Tables 1 and 2) as follows: [Early Pleistocene] CullarBaza-A and B (CU-A, CU-B); [late Early Pleistocene]Puerto Lobo (PL), Loma Quemada (LQ) and Huescar-1(HU-1); [earliest Middle Pleistocene] Cullar Baza-1(CB-1); and the much younger [Late Pleistocene?] CullarBaza-C (CB-C). These sites (except for CU-A, -B) arelocated in a higher stratigraphic level than the LowerPleistocene paleontological/archeological quarries of theOrce-Venta Micena sector (VM ¼ Venta Micena, BL-5 ¼ Barranco Leon-5 and FN-3) (Table 1). The sites PL,LQ, and HU-1 are placed between the Jaramillo andBrunhes polarity zones, indicating a range in age of lessthan 200 kyr.

Agustı and Madurell (2005) identified ‘‘Allophaiomys’’ruffoi from VM and ‘‘Allophaiomys’’ lavocati from FN-3,PL and LQ. Specimens from VM we have viewed and them1s illustrated from FN-3 by Agustı and Madurell (2005)can be duplicated in the type material of ‘‘Allophaiomys’’pliocaenicus from Betfia II, Romania, illustrated by Hir(1998; Fig. 11). The PL and LQ specimens we haveexamined are advanced over the simpler m1 morphotypesreproduced by Hir (1998), and they do not display the

combination of distinctive narrowing of T4-5, tendencytowards closure of the dentine isthmus between T4-5 andthe anteroconid, and the reduced but elongated anteroco-nid shape that characterizes M. lavocati. For now, untilmore specimens have been collected and a quantitativeanalysis has been completed, we prefer to view thespecimens from PL and LQ as Microtus sp.The new paleomagnetic and stratigraphic information

presented in this paper, which place the Cullar Baza-1 siteat 0.75Ma (basically at the Matuyama-Brunhes boundary)also sets a new date, at least in Spain, for the Toringian-Biharian ELMA. As noted above, the extinct water voleArvicola cantianus has been generally used to define thisboundary (see Fejfar et al., 1998; Maul et al., 2000), andhas not previously been recorded from sediments securelydated older than 0.61Ma. But such changes are to beexpected as the stratigraphic and paleomagnetic history ofmore basins becomes established. Since LMAs are definedon the basis of fauna and not, strictly speaking, dates, it isconceivable that the Toringian-Biharian boundary couldbe of different times in different areas of Europe.Theoretically, within a context of mosaic morphologicalevolution, the A. cantianus dental morphology could evolveat different rates in different areas. However, we think thatonce established, a successful arvicolid species wouldexplosively disperse through Europe within a few hundredyears. The modern introduction and dispersal of the extantNorth American muskrat, Ondatra zibethicus, in Europe isa good example (Danell, 1996). Also, the paucity of

ARTICLE IN PRESS

Fig. 13. Detailed correlation of Matuyama/Brunhes boundaries. The upper Matuyama to lower Brunhes magnetozone boundary correlation for the north

and east sectors of the Baza Basin, shows the diachronous development of sedimentary facies. The palustrine events at Cullar and B. Canadas are not

contemporaneous. These sedimentary events were controlled by paleo-geographic location at Cullar and by neo-tectonic uplift nearby at B. Canadas. Here

climate change was a secondary effect. In the PL section, paleo-currents switch direction between the base and top of the section as a consequence of the

uplift in Botardo hill.



appropriate sediments for radiometric dating and theminimal number of long stratigraphic sequences formagnetostratigraphic determinations in other Europeansettings can leave considerable flexibility in estimates of theToringian-Biharian boundary.

6. Chronostratigraphy and geological implications

Paleomagnetic polarity changes are worldwide eventswith the advantage of chronostratigraphic horizons, that ofproviding a glimpse into the events and processes happen-ing at that specific time. Contemporaneous features andinfluences such as paleo-geography, paleo-environments,fauna and neo-tectonics can be compared accurately atmagnetozone boundaries or interpolated between bound-aries. The Early Pleistocene has boundaries that areapproximated by the limits of two normal polarity chrons,the Olduvai (C2n) and the Brunhes (C1n). For now, thereare three sections in the Baza Formation with one or moreof these ‘boundary’ reversals: Cullar, Huescar-Puerto Lobo(both from this report) and the composite Orce sections(Scott et al., 2007). These sections represent the processes

of accumulation at three distinct points around the edges ofthe Baza Basin, the south-central, the north-eastern and thesouth-eastern, respectively, and provide an opportunity fordirect comparison and contrast (Figs. 12 and 13).As a general observation, the Pliocene–Lower Pleisto-

cene boundary (top of Olduvai zone) in the Orce area is at900 asl (Salar Valley; Scott et al., 2007), compared to thesame zone in Cullar, also at 900masl. The Lower–MiddlePleistocene boundary (base of Brunhes zone) in Cullar is at965m (asl.) and in Huescar-Puerto Lobo at 955m (asl.),but as of yet is not identified around Orce owing to erosionand/or non-deposition.Specific comparisons of paleo-environments can begin at

the start of the Pleistocene, when the Orce area, which hadbeen experiencing a period of protracted lacustrinedeposition, was the site of an advancing fluvial systemcoming from an eastern highlands. Meanwhile in Cullar,the alluvial fan deposition, coming from the southernhighlands continued. As the Middle Pleistocene begins, theHuescar-Puerto Lobo area had been changing from pondsand marshes fringing the northern Basin margins to small,local fans and alluvial drainages coming from an emergentneo-tectonic structure (Botardo Hill) (Fig. 13). Simulta-neously at Cullar, palustrine facies was prograding ontothe Cullar fan, with an expansion of palustrine and distalalluvial environments replacing the mid-fan and alluvialfacies.Sedimentation rate in fine grain deposits of the Orce area

was �10 cm/kyr (Scott et al., 2007) through the EarlyPleistocene, while in the Cullar area the sedimentation ratewas slower until after the Jaramillo subchron. The Cullararea experienced an accelerated sedimentation after theJaramillo and into the Brunhes, reaching equivalent ratesto those from the Early Pleistocene deposits of Orce. Thisacceleration of sedimentation rate in the Cullar area was along-term process interpreted as a product of the prograd-ing paleo-lake Baza and its marginal valley floor (Figs. 14and 15). Other processes, such as neo-tectonic uplift andchanging paleo-climates, were secondary variables to theCullar section’s specific paleo-geographic location. How-ever neo-tectonic activity, on both the regional and localscale, was the dominant process at the Huescar marginalsites. Meanwhile, in the central facies of the paleo-LakeBaza there was continuous sedimentation in which paleo-climate was the primary triggering factor (Gibert L. et al.,2001, 2007; Gibert L, 2006).The chronology and biostratigraphy of the Baza Basin’s

Pleistocene fossil vertebrate sites starts in the Orce area,with MN17 fauna (Fuentenueva-1 quarry) at �1.5Ma,�25m above the Olduvai normal zone. The paleontologi-cal/archeological quarries of Venta Micena (1.3Ma),Barranco Leon (1.25Ma) and Fuentenueva-3 (1.2Ma)provide an Early Pleistocene fauna �50m above theOlduvai normal zone (Scott et al., 2007). Then the fossilsites below the Matuyama/Brunhes boundary in theHuescar area (Puerto Lobo, Loma Quemada and Hues-car-1) provide a late Early Pleistocene fauna at 0.9Ma.

ARTICLE IN PRESS

Table 2

Chronostratigraphic sequence and biozonation for the Baza Basin

A chronostratigraphic summary is shown for the paleontological sites in

the Baza Basin that can be correlated to the Geomagnetic Polarity Time

Scale. Also shown are the associated continental stages and preliminary

biozones for the Baza Basin.



ARTICLE IN PRESS

Fig. 14. Age versus sediment accumulation. Sediment accumulation rates are compared between the Cullar and Orce sections, based on magnetozone

boundaries. At the position of the Cullar section, the aggrading valley floor environments (palustrine/lacustrine) arrived soon after the Jaramillo subchron,

which significantly increased the sediment accumulation rate. Projecting this rate to the upper strata, gives an approximate age of 600Kya. Note that the

top of the Orce sections is an erosion surface, and that the uppermost strata are pre-Jaramillo in age (Scott et al., 2007). Therefore, this figure shows a

minimum accumulation rate for Orce, so that the associated fossil quarries might be slightly older than shown. In Cullar section, the reference

magnetozone boundaries are used as ‘hinge’ points for accumulation trends in a second refined curve (following McMillan and Stoner, 2005).

Fig. 15. Depositional model for Cullar area. Schematic model which explain changes in sedimentation rate across the Cullar margin during the Late

Pliocene to Middle Pleistocene. Neogene sedimentation starts slowly, with the onlapping alluvial fan at �2.1Ma. A change to higher sedimentation rates,

owing to the aggrading valley floor, finally reaches the Cullar section about 0.9Ma as the paleo-Baza Basin continues to fill. This process of net

accumulation stops sometime after 0.6Ma, and reverses into an erosional mode, that continues today.



Then immediately above the Matuyama/Brunhes bound-ary is the paleontological/archeological quarry at CullarBaza-1 that provides an initial fauna from the MiddlePleistocene at 0.75Ma. And finally, the Cullar Baza-C site(Agustı et al., 1999), which is from post-Baza Formationdeposits, provides a new opportunity to examine faunafrom approximately the Middle/Late Pleistocene boundary(�0.1Ma).

7. Conclusions

� A study of the lithostratigraphy, magnetostratigraphyand micro-mammal paleontology was made at twosections in Quaternary deposits of the Baza Basin.� Magnetostratigraphy of the Cullar section (81m) has

located both the Pliocene–Pleistocene boundary and theLower Pleistocene–Middle Pleistocene boundary. Thepaleontological/archeological quarry Cullar Baza-1 isonly 2m above the Matuyama-Brunhes (Lower–MiddlePleistocene) boundary. Six major polarity zones havebeen identified in this section. The normal zones arecorrelated to the Olduvai (C2n), Jaramillo C1r.1n), andthe early part of the Brunhes (C1n) chrons. The base ofCullar section is dated at �2.0Ma.� The top of both studied sections are some of the last

deposits before stream piracy captured the drainage ofthe previously endorheic Baza Basin. Extrapolation ofsedimentation rates suggests an age for the top of theCullar section at around 600Kya. This indicates that theopening of the Basin occurred during the MiddlePleistocene, around 600Kya.� An age of �0.75Ma can be given to the extensive Cullar

Baza-1 fauna and lithic artifacts.� Magnetostratigraphy of the Puerto Lobo sections

(31m), 25 km to the north near Huescar has also locatedthe Lower Pleistocene–Middle Pleistocene boundary.Two polarity zones have been identified in this sectionand are correlated to the latest Matuyama (C1r.1r) andthe initial part of the Brunhes (C1n) chrons.� An age of 0.9Ma can be given to the paleontological

sites of Huescar-1 and Puerto Lobo.� The change from the Biharian to the Toringian stages

can be approximated by the Matuyama/Brunhes polar-ity change.� Throughout the Pleistocene, local and regional neo-

tectonic activities have played important roles, alongwith the changing climate, in influencing the distributionof depositional facies and paleo-environments foundwithin the Baza Basin. However, paleo-geographiclocation will determine when, and where these influencesare manifested as sedimentary deposits.� The presence of early humans in the Baza Basin can be

found at 1.3–1.2Ma in the Orce area (previous work), at0.75Ma in the Cullar area, and again at �0.7Ma in theHuescar area.

Acknowledgments

We are grateful to the Paleontological Inst. Crusafontand Dr. A. Ruiz-Bustos for facilitating the review of thefossil material. We thank Dr. F. Tortosa for facilitatingdetailed digital elevation maps of the area, L. Smeenk forlaboratory assistance and Dr. C. Ferrandez-Canyadell forhis useful comments which improved the manuscript. Thisproject was funded in part by the generous support ofEarthwatch Institute a National Science Foundation grant(EAR-0207582) and project CGL2005-05337 BTE from theSpanish Government.

References

Agustı, J., 1984. Bioestratigrafıa de los depositos Plio–Pleistocenos de la

depresion Guadix-Baza (Prov. Granada). Paleontologia i Evolucio 18,

13–18.

Agustı, J., 1986. Continental mammal units of the Plio–Pleistocene from

Spain. Mem. Soc. Geol. It. 31, 167–173.

Agustı, J., 1991. The Allophaiomys complex in southern Europe. Geobios

25, 133–144.

Agustı, J., Madurell, J., 2005. Los arvicolidos (Muroidea, Rodentia,

Mammalia) del Pleistoceno inferior de Barranco Leon y Fuente Nueva

3 (Orce, Granada), datos preliminaries. In: Toro, I., Agustı, J.,

Martınez-Navarro, B. (Eds.), El Pleistoceno inferior del Barranco

Leon y Fuente Nueva 3, Orce (Granada), Monografias de Arqueolo-

gia. Junta de Andalucıa, Sevilla, pp. 137–145.

Agustı, J., Moya-Sola, S., Pons-Moya, J., 1987. La sucesion de mamıferos

en el Pleistoceno inferior de Europa: proposicion de una nueva escala

Biostratigrafica. Paleontologia i Evolucio Mem. Esp. 1, 287–295.

Agustı, J., Oms, O., Pares, J.M., 1999. Calibration of the Early–Middle

Pleistocene transition in the continental beds of the Guadix-Baza Basin

(SE Spain). Quaternary Sciences Reviews 18, 1409–1417.

Agustı, J., Oms, O., Pares, J.M., 2007. Biostratigraphy, paleomagnetism

and geology of the Orce ravine (Southern Spain). Comment on the

paper by Gibert et al., 2006 [Evaluation of the Olduvai sub-chron in

the Orce ravine (SE Spain). Implications for Plio–Pleistocene mammal

biostratigraphy and the age of Orce archaeological sites]. Quaternary

Sciences Reviews 26, 568–572.

Alberdi, M.T., Alcala, L., Azanza, B., Cerdeno, E., Mazo, A., Morales, J.,

Sese, C., 1989. Consideraciones bioestratigraficas sobre la fauna de

Vertebrados fosiles de la cuenca de Guadix-Baza (Granda, Espana).

In: Alberdi, M.T., Paolo, B. (Eds.), Trabajos sobre el Neogeno-

Cuaternario. Museo Nacional de Ciencias Naturales, Madrid, pp.

347–355.

Alberdi, M.T., Alonso, M.A., Azanza, B., Hoyos, M., Morales, J., 2001.

Vertebrate taphonomy in circum-lake environments: three cases in the

Guadix-Baza Basin (Granada, Spain). Palaeogeography, Palaeoclima-

tology, Palaeoecology 165, 1–26.

Alcalde, G., Agustı, J., Villalta, J.F., 1981. Un nuevo Allophaiomys

(Arvicolidae, Rodentia, Mammalia) en el Pleistoceno inferior del sur

de Espana. Acta Geologica Hispanica 16, 203–205.

Alfaro, P., Delgado, J., Sanz de Galdeano, C., Galindo-Zaldıvar, J., Garcıa-

Tortosa, F.J., Lopez-Garrido, A.C., Lopez-Casado, C., Marın-Lechado,

C., Gil, A., Borque M.J., in press. The Baza fault: a major active

extensional fault in the central Betic Cordillera (south Spain).

International Journal of Earth Sciences, doi:10.1007/500531-007-0213-z.

Brunet-Lecomte, P., 1988. Les campagnols souterrains (Terricola,

Arvicolidae, Rodentia) actuels et fossiles d’Europe occidentale.

Ph.D. Thesis, Universite de Bourgogne, Dijon, France.

Calvache, M.L., Viseras, C., 1997. Long-term control mechanisms of

stream piracy processes in southeast Spain. Earth Surface Processes

and Landforms 22, 93–105.



Chaline, J., 1972. Les rongeurs du Pleistocene moyen et superieur de

France. Cahiers de Paleontologie, 1–410.

Channell, J.E.T., Mazaud, A., Sullivan, P., Turner, S., Raymo, M.E.,

2002. Geomagnetic excursions and paleointensites in the Matuyama

Chron at Ocean Drilling Program Sites 983 and 984 (Iceland Basin).

Journal of Geophysical Research 107, doi:10.1029/2001JB000491.

Coe, R.S., Singer, B.S., Pringle, M.S., Zhao, X., 2004. Matuyama-Brunhes

reversal and Kamikatsura event on Maui: paleomagnetic directions,40Ar/39Ar ages and implications. Earth and Planetary Science Letters

222, 667–684.

Coltorti, M., Cremaschi, M., Delitala, M.C., Esu, D., Fornaseri, M.,

McPherron, A., Nicoletti, M., van Otterloo, R., Peretto, C., Sala, B.,

Schmidt, V., Sevink, J., 1982. Reversed magnetic polarity at an early

Lower Paleolithic site in Central Italy. Nature 300, 173–176.

Coltorti, M., Feraud, G., Marzoli, A., Peretto, C., Ton-That, T.,

Voinchet, P., Bahain, J.-J., Minelli, A., Thun Hohenstein, U., 2005.

New 40Ar/39Ar stratigraphic and paleoclimatic data on the Isernia La

Pineta Lower Paleolithic site, Molise, Italy. Quaternary International

131, 11–22.

Cuenca-Bescos, G., Canudo, J.I., Laplana, C., 2001. La sequence des

rongeurs (Mammalia) des sites du Pleistocene inferieur et moyen

d’Atapuerca (Burgos, Espagne). L’Anthropologie 105, 115–130.

Cuenca-Bescos, G., Laplana, C., Canudo, J.I., 1999. Biochronological

implications of the Arvicolidae (Rodentia, Mammalia) from the Lower

Pleistocene hominid-bearing level of Trinchera Dolina 6 (TD 6,

Atapuerca, Spain). Journal of Human Evolution 37, 353–373.

Danell, K., 1996. Introduction of aquatic rodents: lessons of the Ondatra

zibethicus invasion. Wildlife Biology 2, 213–220.

Fejfar, O., Heinrich, W.-D., Lindsay, E.H., 1998. Updating the neogene

rodent biochronology in Europe. In: van Kolfschoten, Th., Gibbard,

P.L. (Eds.), The Dawn of the Quaternary. Mededelingen Nederlands

Instituut voor Toegepaste Geowetenschappen, Haarlem, pp. 533–554.

Garcıa, N., Arsuaga, J.L., 1999. Carnivores from the Early Pleistocene

hominid-bearing Trinchera Dolina 6 (Sierra de Atapuerca, Spain).

Journal of Human Evolution 37, 415–430.

Garces, M., Agustı, J., Pares, J.M., 1997. Late Pliocene continental

magnetochronology in the Guadix-Baza Basin (Betic Ranges, Spain).

Earth and Planetary Science Letters 146, 677–687.

Gibert, J., Gibert, L., Maestro, E., Iglesias, A., 1998. Two oldowan

assemblages in the Plio–Pleistocene deposits of the Orce region, SE

Spain. Antiquity 72, 17–25.

Gibert, J., Gibert, L., Ferrandez-Canyadell, C., Iglesias, A., Gonzalez, F.,

2001. Venta Micena, Barranco Leon-5 and Fuentenueva-3: three

archaeological sites in the early Pleistocene deposits of Orce, south-east

Spain. In: Milliken, S., Cook, J. (Eds.), A Very Remote Period Indeed.

Papers on the Palaeolithic presented to Derek Roe. Oxbow Books,

Oxford, pp. 144–152.

Gibert, J., Gibert, L., Vicente, O., Garcıa, E., Ferrandez, C., Iglesias, A.,

2002. Excavacion de urgencia en el yacimiento paleontologico

Fuentenueva-1 (Orce, Granada). Anuario Arqueologico de Andalucıa.

Actividades de Urgencia 1, 135–142.

Gibert, J., Gibert, L., Ferrandez, C., Iglesias, A., Gonzalez, F., 2006.

Venta Micena, Barranco Leon-5 and Fuentenueva-3: three archae-

ological sites in the Early Pleistocene deposits of Orce, south-east

Spain. In: Ciochon, R.L., Fleagle, J.G. (Eds.), The Human Evolution

Source Book. Prentice-Hall, Upper Saddle River, NJ, pp. 327–335.

Gibert, L., 2006. Analisis de facies y magnetostratigrafia de la cuenca de

Baza. Ph.D. Thesis, Univ. Politecnica de Catalunya, Manresa, Spain.

Gibert, L., Ferrandez, C., Scott, G.R., 2001. Plio–Pleistocene lacustrine

sedimentation in the Baza Basin (SE Spain) and its relation with

climatic shifts. European Space Agency (ESA) 463, 171–175.

Gibert, L., Sanz de Galdeano, C., Alfaro, P., Scott, G.R., Lopez Garrido,

A.C., 2005. Seismic induced Pleistocene landslides in deltaic deposits of

the Baza Basin (SE Spain). Sedimentary Geology 179, 279–294.

Gibert, L., Scott, G.R., Ferrandez-Canadell, C., 2006. Evaluation of the

Olduvai sub-chron in the Orce ravine (SE Spain). Implications for

Plio–Pleistocene mammal biostratigraphy and the age of Orce

archaeological sites. Quaternary Science Reviews 25, 507–525.

Gibert, L., Scott, G.R., Ferrandez-Canadell, C., 2007. Reply to Comment

by Agustı, et al., on the paper [Evaluation of the Olduvai sub-chron in

the Orce ravine (SE Spain). Implications for Plio-Pleistocene mammal

biostratigraphy and the age of Orce archaeological sites]. Quaternary

Science Reviews 26, 573–576.

Gibert, L., Ortı, F., Rosell, L., 2007. Plio–Pleistocene lacustrine evaporites

of the Baza Basin (Betic chain, SE Spain). Sedimentary Geology 200,

89–116.

Graham, J.W., 1949. The stability and significance of magnetism in

sedimentary rocks. Journal of Geophysical Research 54, 131–167.

Gradstein, F.M., Ogg, J.G., Smith, A.G., Agterberg, F.P., Bleeker, W.,

Cooper, R.A., Davydov, V., Gibbard, P., Hinnov, L., House, M.R.,

Lourens, L., Luterbacher, H.P., McArthur, J., Melchin, M.J., Robb,

L.J., Shergold, J., Villeneuve, M., Wardlaw, B.R., Ali, J., Brinkhuis,

H., Hilgen, F.J., Hooker, J., Howarth, R.J., Knoll, A.H., Laskar, J.,

Monechi, S., Powell, J., Plumb, K.A., Raffi, I., Rohl, U., Sanfilippo,

A., Schmitz, B., Shackleton, N.J., Shields, G.A., Strauss, H., van Dam,

J., van Kolfschoten, T., Veizer, J., Wilson, D., 2004. A geological time

scale 2004. Columbia University Press, New York.

Guo, B., Zhu, R., Florindo, F., Ding, Z., Sun, J., 2002. A short, reverse

polarity interval within the Jaramillo subchron: evidence from the

Jingbian section, northern Chinese Loess Plateau. Journal of

Geophysical Research 107, doi:10.1029/2001JB000706.

Heinrich, W.-D., 1990. Some aspects of the evolution and biostratigraphy

of Arvicola (Mammalia, Rodentia) in the central European Pleisto-

cene. In: Fejfar, O., Heinrich, W.-D. (Eds.), International Symposium

Evolution, Phylogeny and Biostratigraphy of Arvicolids (Rodentia,

Mammalia). Geological Survey, Prague, pp. 165–182.

Hernandez Fernandez, M., Azanza, B., Alvarez Sierra, M.A., 2004.

Iberian Plio–Pleistocene biochronology: micromammalian evidence

for MNs and ELMAs calibration in southwestern Europe. Journal of

Quaternary Science 19, 605–616.

Hir, J., 1998. The Allophaiomys type-material in the Hungarian

collection. In: Martin, R.A., Tesakov, A. (Eds.), The Early Evolution

of Microtus, Vol. 2, Paludicola, pp. 28–36.

Hoffman, K.A., 1984. A method for the display and analysis of

transitional paleomagnetic data. Journal of Geophysical Research

89, 6285–6292.

Kormos, T., 1930. Neue wuhlmause aus dem Oberpliozan von Puskpok-

furdo. Neues Jahrbuch fur Mineralogie. Geologie und Paleontologie

Series B 69, 323–346.

Laplana, C., Cuenca-Bescos, G., 2000. Una nueva especie de Microtus

(Allophaiomys) (Arvicolidae, Rodentia, Mammalia) en el Pleistoceno

inferior de la Sierra de Atapuerca (Burgos, Espana). Revista Espanola

de Paleontologia 15, 77–87.

van der Made, J., 1999. Ungulates from Atapuerca TD6. Journal of

Human Evolution 37, 389–413.

van der Made, J., Mazo, A.V., 2001. Spanish Pleistocene Proboscidean

diversity as a function of climate. The World of Elephants-Interna-

tional Congress, Consiglio Nazionale delle Ricerche Rome,

pp. 214–218.

Maul, L.C., Rekovets, L., Heinrich, W.-D., Keller, T., Storch, G., 2000.

Arvicola mosbachensis (Schmidtgen 1911) of Mosbach 2: a basic

sample for the early evolution of the genus and a reference for

further biostratigraphical studies. Senckenbergiana Lethaea 80,

129–147.

Mazo, A.V., Sese, C., Ruiz-Bustos, A., Pena, J.A., 1985. Geologıa y

paleontologıa de los yacimientos Plio–Pleistocenos de Huescar

(Depresion de Guadix-Baza, Granada). Estudios Geologicos 41,

467–493.

McMillan, D.G., Stoner, J.S., 2005. Optimizing the depth-age transforma-

tion. EOS trans. AGU, 86, Fall Meeting Suppl., Abstract U43A-0826.

McMillan, D.G., Constable, C.G., Parker, R.L., 2002. Limitations on

stratigraphic analyses due to incomplete age control and their

relevance to sedimentary paleomagnetism. Earth and Planetary

Science Letters 201, 509–523.

van der Meulen, A.J., 1978. Microtus and Pitymys (Arvicolidae) from

Cumberland Cave, Maryland, with a comparison of some New and

ARTICLE IN PRESSL. Gibert et al. / Quaternary Science Reviews 26 (2007) 2067–20892088


Old World species. Annals Carnegie Museum of Natural History 47,

101–145.

Ortız, J.E., Torres, T., Lamas, J.F., Canoira, L., Garcıa Alonso, L.,

Garcıa de la Morena, P., Lucini, M., 2000. Datacion de los

yacimientos paleontologicos de la Cuenca de Guadix-Baza (Sector

Cullar-Baza, Granada) y primera estimacion de la edad de apertura de

la cuenca mediante el metodo de racemizacion de aminoacidos.

Geogaceta 28, 109–112.

Ortız, J.E., Torres, T., Julia, R., Delgado, A., Llamas, F.J., Soler, V.,

Delgado, J., 2004. Numerical dating algorithms of amino acid

racemization ratios from continental ostracodes. Application to the

Guadix-Baza Basin (southern Spain). Quaternary Science Reviews 23,

717–730.

Pasa, A., 1947. I mammiferi di alcune antiche breccie veronesi. Memorie

del Museo Civico di Storia Naturale di Verona 1, 1–111.

Ruiz-Bustos, A., 1976. Estudio sistematico y ecologico sobre la fauna del

Pleistoceno Medio en las depresiones granadinas. El yacimiento de

Cullar-Baza-1. Trabajos y Monografıas del Departamento de Zoologıa

1, 1–321.

Ruiz-Bustos, A., 1984. El yacimiento paleontologico de Cullar Baza-1.

Investigacion y Ciencia 91, 20–28.

Ruiz-Bustos, A., 1999. The role of the water voles (Arvicola, Rodentia) in

the Quaternary. Estudios Geologicos 55, 89–95.

Ruiz-Bustos, A., Michaux, J., 1976. Le site prehistorique nouveau de

Cullar de Baza-1. Geologie Mediterraneenne 3, 173–182.

Sanz de Galdeano, C., Vera, J.A., 1992. Stratigraphic record and

paleogeographical context of the Neogene basins in the Betic

Cordillera, Spain. Basin Research 4, 21–36.

Scott, G.R., Hotes, S.A., 1996. The reversal test: an examination of

secondary directions. Geophysical Research Letters 23, 1805–1808.

Scott, G.R., Gibert, L., Gibert, J., 2007. Magnetostratigraphy for the Orce

region (Baza Basin), SE Spain: New chronologies for Early Pleistocene

faunas and hominid occupation sites. Quaternary Sciences Reviews 26,

415–435.

Sese, C., 1989. Micromamıferos del Mioceno, Plioceno y Pleistoceno de la

cuenca de Guadix-Baza (Granada). In: Alberdi, M.T., Bonadonna, F.

(Eds.), Geologıa y Paleontologıa de la Cuenca de Guadix-Baza. Museo

Nacional de Ciencias Naturales, Madrid, pp. 187–215.

Singer, B., Brown, L., 2002. The Santa Rosa Event: Ar/Ar and

paleomagnetic results from the Valles rhyolite near Jaramillo Creek,

Jemez Mountains, New Mexico. Earth and Planetary Science Letters

197, 51–64.

Soria, F.J., Lopez Garrido, A.C., Vera, J.A., 1987. Analisis estratigrafico y

sedimentologico de los depositos neogeno-cuaternarios en el sector de

Orce (depresion de Guadix-Baza). In: Moya-Sola, S., Agustı, J.,

Gibert, J., Vera, J.A. (Eds.), Geologıa y Paleontologıa del Pleistoceno

Inferior de Venta Micena. Institut Paleontologic Dr. M. Crusafont,

Sabadell, pp. 11–34.

Torres, T., Llamas, J.F., Canoira, L., Garcia-Alonso, P., Garcia-Cortes,

A., Mansilla, H., 1997. Amino acid chronology of the Lower

Pleistocene deposits of Venta Micena (Orce, Granada, Andalusia,

Spain). Organic Geochemistry 26, 85–97.

Unay, E., Emre, O., Erkal, T., Kecer, M., 2001. The rodent fauna from the

Adapazari pull-apart basin (NW Anatolia): its bearing on the age of

the North Anatolian fault. Geodinamica Acta 14, 169–175.

Vega Toscano, L., 1989. Ocupaciones humanas en el Pleistoceno de la

Depresion de Guadix-Baza: elementos de discusion. In: Alberdi, M.T.,

Bonadonna, F. (Eds.), Geologıa y Paleontologıa de la Cuenca de

Guadix-Baza. Museo Nacional de Ciencias Naturales, Madrid, pp.

327–345.


Documents

Author's personal copy - University of Minnesota et al... · aDepartment Enginyeria Minera i Recursos Naturals, Universitat Polite`cnica de Catalunya, Av. Bases de Manresa 61-73,