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We report new rock magnetic results from a cave in the “Sierra de Atapuerca” (Burgos, North of Spain), that is one of the most important archaeological and palaeontological sites of Lower to Middle Pleistocene in Europe. Our samples are taken in cave sediments of Gran Dolina Cave. Rock magnetic analyses allowed us to determine changes in grain size, composition, and concentration in both cave-entrance and cave-interior sediments. Generally, the cave-entrance sediments are characterized by a high concentration of magnetic minerals while the cave-interior presents a more variable concentration. Because rock magnetic properties, in particular the iron oxides, are affected by environmental factors (such as the intensity of physical and chemical weathering) they offer an important reconstruction proxy for better understanding the paleoenvironmental conditions at the time the earliest hominins began to migrate into Europe. The main goal of this study is to identify magnetic proxies that help to better reconstruct the environmental conditions of this archaeological and palaeontological site., Financial support for this work was also obtained from Junta de Castilla y León and from MINECO Grant CGL2017-89603-R (JMP).

We present the results of a new dating study carried out at Lunery-la Terre-des-Sablons (LTS) and Brinay-la Noira (BN), two key Lower Palaeolithic sites located in deposits associated to the Cher River (Middle Loire Catchment, France). These sites preserve abundant Mode 1 and Mode 2 lithic industries, and are considered as among the oldest evidence of hominin presence in Western Europe north of the 45°N latitude. Following a multi-technique approach combining electron spin resonance (ESR), single-grain thermally-transferred optically stimulated luminescence (TT-OSL) dating of quartz grains and palaeomagnetism, we obtained new chronological constraints for the sedimentary sequence, and the associated lithic assemblages, at the two sites. The new independent dating results derived from each method are consistent and in overall agreement with existing ESR and terrestrial cosmogenic nuclide (TCN) burial age estimates, except for the Lowermost Unit 3 at LTS. By integrating all of the previous and new dating results, we derive combined age estimates of 772-735 ka and 665 ± 29 ka for the fluvial sands at LTS (Unit 1) and BN, respectively. These two distinct aggradation phases may tentatively be correlated to interglacial/glacial transitions associated with Marine Isotope Stage (MIS) 19-18 for the former and MIS 17-16 for the latter. At BN, an age range of 638–676 ka may be proposed for the hominin occupation after combining numerical age results and geological evidence. This result is consistent with the initial chronology proposed by Moncel et al. (2013) [Moncel, M.H., Despriee, J., Voinchet, P., Tissoux, H., Moreno, D., Bahain, J. J., Courcimault, G., Falgueres, C. (2013). Early evidence of Acheulean settlement in north-western Europe – la Noira site, a 700 000 year-old occupation in the Centre of France. Plos One, 8(11): 1–22] and confirms that BN is among the oldest Acheulean occurrences in Western Europe. At LTS, the mean age of 710 ± 50 ka obtained for the sandy layer in Unit 3 provides a minimum age constraint for the archaeological level located below. The major sedimentary disconformity observed between the fluvial deposits and the underlying pebble layers hosting the lithic artefacts suggests that the true age of the artefacts might be significantly older, probably Early Pleistocene given their similarities with other Mode 1 assemblages identified in Western Europe. However, further refinement of the Mode 1 chronological inference at LTS remains difficult at this stage. Finally, these new dating results show the importance of using the Multiple Centre approach for ESR dating of quartz grains, and confirm the value of combining different dating methods in order to build more robust chronologies for Lower Palaeolithic sites in Europe. From a methodological point of view, the dating results presented here are especially encouraging for the reliability of the ESR method applied to optically bleached quartz grains. This is one of the very first studies demonstrating that quartz samples independently dated by two different laboratories may produce generally reproducible ESR age results.

Centro Nacional de Investigación sobre la Evolución Humana (or National Research Centre on Human Evolution, CENIEH) is located in Burgos, northern Spain. The centre is dedicated to human evolution research worldwide, including Atapuerca, a world heritage archaeological site where the oldest human fossil in Europe to date have been discovered. To support the needs of characterising geological and sedimentological context of archaeological sites, the institute also features a wide range of geological analysis (e.g., Laser diffraction grain size analyser, XRD, XRF, Raman Spectroscopy, SEM, Micro CT, Digital mapping and 3D analysis) and geochronology laboratories (including palaeomagnetism, OSL, ESR and U-series). In 2020, a new cosmogenic nuclide dating research line has initiated to strengthen the existing geochronological capabilities in the centre, particularly, at timescales of early-mid Pleistocene and beyond. To date, we have established a procedure for routine quartz separation and 10Be-26Al extraction. Current projects include 10Be-26Al burial/isochron dating of cave deposits, fluvial terraces and artefacts in the context of archaeological and landscape evolution research. In this paper, we present a general setup of the laboratory, its capacity and current projects as well as future prospective.

Located within the Beni Fouda intramontane basin, the Oued Boucherit area (Guelta Zerga, North East Algeria) hosts a unique succession of archaeological and palaeontological deposits spanning from the late Pliocene to the Early Pleistocene. While the recent work by Sahnouni et al., (2018) mostly focused on the two Oldowan archaeological levels AB-Lw and AB-Up, we present here an updated overview of the entire Oued Boucherit sequence, resulting from a long-term multidisciplinary investigation that started in 1992. In particular, we report for the first time a description of the oldest palaeontological levels dated to >3 Ma, and of the uppermost archaeological level hosting Acheulean artefacts. The age-depth model initially proposed by Sahnouni et al. (2018) was further extended to chronologically constrain the whole sequence, which spans from ∼3.93 Ma at the bottom to ∼1.65 Ma at the top. The Oued Boucherit sedimentary sequence records the earliest evolutionary steps of lithic technology, with early Oldowan assemblages at Ain Boucherit dated to about 2.44 Ma (AB-Lw) and 1.92 Ma (AB-Up) Ma, followed by the ∼1.77-1.72 Ma assemblages of Ain Hanech and El Kherba showing more derived features, and the appearance of the Acheulean technology, dated to ∼1.67 Ma. This chonostratigraphic framework indicates that the Oued Boucherit area (, Research grants are awarded to M. Sahnouni and/or J. van der Made and/or J.M. Parés by CNRPAH, MINICIU (PGC 2018-095489-B-I00), MINECO (HAR 2013-41351-P & CGL 2017-89603-R) (Spain), The L.S.B. Leakey Foundation (San Francisco, CA, USA), Wenner-Gren Foundation (New York, USA), European Research Council (FP7-People-CIG2993581) (Brussels, Belgium), and Stone Age Institute (Bloomington, IN, USA). Mathieu Duval's research has been funded by the Australian Research Council Future Fellowship Grant FT150100215 and Spanish Ramón y Cajal Fellowship RYC 2018-025221-I.

The Cenozoic sedimentary basins in the Iberian Peninsula show a change from long-term basin infill to incision, a transition that indicates a period of major drainage reorganization that culminated in the throughflow of the networks to the Atlantic and Mediterranean oceans. Both the cause of the transition from aggradation to degradation and the linkages to tectonic, climatic, and geomorphic events hinge on the chronology of the fluvial network incision and excavation of the basin’s sedimentary fills. In this paper, we describe the first chronologic data on the highest fluvial terraces of the upper area of the Ebro River, one of the largest fluvial systems in the Iberian Peninsula, to determine the onset of incision and excavation in the basin. For this purpose, we combine electron spin resonance (ESR) and paleomagnetism methods to date strath terraces found at 140, 90, and 85 m above the current river level. Our results show ages of ca. 1.2 and 1.5 Ma for the uppermost river terraces in the upper Ebro catchment, constraining the minimum age of the entrenchment of the upper Ebro River.

M. Bartz, L.J. Arnold, M. Demuro, M. Duval, G.E. King, G. Rixhon, C. Alvarez Posada, J.M. Pares, H. Bruckner

Magnetostratigraphy has proven to be a powerful and versatile method as well the first line of defence for dating sediments. When properly anchored to the Geomagnetic Polarity Time Scale (GPTS), chron boundaries provide a basis for numerical dating by correlating the local magnetostratigraphy to the GPTS. A caveat and intrinsic limitation when anchoring magnetic stratigraphy to the GPTS is that we deal with essentially a binary code, a sequence of normal and reverse polarity zones. To overcome such limitation biostratigraphy or (ideally) numerical (absolute) age dating is required. Unfortunately, numerical dating of sediments is typically hampered by the lack of amenable minerals for the application of standard methods such as Ar-Ar, requiring thus the use of less conventional methods. Burial dating is possible using methods such as Electron Spin Resonance (ESR) on optically bleached quartz grains. Similar to luminescence, ESR is a paleodosimetric method that provides the time elapsed since the last exposure of quartz grains to natural sun light. Cave sediments are particularly amenable for paleodosimetric methods, as sediments are preserved in the dark and the ESR signal should survive over the geologic history of the deposits. On the down side, we date the moment when the quartz grain enters the karst system, not its deposition. If the transit time is too long, this might be an issue and we would be significantly overestimating the true burial age. Caves at Atapuerca (N Spain) hold the richest Quaternary paleontological record in Eurasia, including fossils and lithic tools. Sediments in these caves have been traditionally dated via magnetostratigraphy by identifying the Matuyama-Brunhes reversal (0.78 Ma) thus providing the Lower to Middle Pleistocene boundary. Nevertheless, the appearance of older sediments in the caves required the combination of paleomagnetism with methods such as ESR to interpret older intra-Matuyama Subchrons. In the deepest levels of the Gran Dolina cave, close to the floor of the cavity, a number of short intervals of normal polarity have been identified in the fluviatile sediments belonging to TD1 unit, which we interpret in terms of Subchrons using ESR ages of quartz grains. We will discuss both paleomagnetic data and interpret the magnetic polarity stratigraphy in the view of the ESR ages obtained from the Multiple Centre (MC) approach.

The Galería Complex is a cave sediment succession at the Atapuerca paleoanthropological site (Burgos, Spain) that offers detailed environmental information about the late Middle Pleistocene, especially the period between marine oxygen isotope stages MIS10 and MIS7. Previous studies have reconstructed the chronology and detailed the environmental development of this key succession. We introduce rock magnetic climate proxies from the sedimentary units of the Galería succession that we correlate with the global climate record as represented by the marine oxygen isotope record. The cave sediment sequence consists of five infilling phases, four of which were sampled at high resolution across a 5 m thick composite profile. We propose a novel goethite climate proxy along with a frequently used ultrafine ferrimagnetic mineral proxy for paleoclimate reconstruction and detailed chronostratigraphic correlation with isotope stages and substages MIS10/MIS10-9, MIS9e-a and MIS8. The proxies reveal new paleoenvironmental information about paleoprecipitation and indicate that MIS9e was a humid (∼650 mm/year maximum annual precipitation) and intense interglacial in northern Spain that declined in steps into the globally weak glacial stage MIS8. MIS8 consisted of drier periods with 430–510 mm/year annual precipitation and at least one humid substage (600 mm/year)., Junta de Castilla y León (Spain) and the European Regional Development Fund (ERDF) (BU235P18) and the research projects CGL2016-77560-C2, CGL2018-093925-B-C31, and CGL2017-89603-R of the Spanish Ministry of Science and Innovation and PID2019-108753 GB-C21 and PID2019-105796 GB-I00 of the Spanish State Research Agency (AEI/10.13039/501100011033) and ERDF funding (European Union). B. Bradák acknowledges financial support from project BU235P18 (Junta de Castilla y León, Spain) and the European Regional Development Fund (ERDF). M. Calvo-Rathert acknowledges funding from the Fulbright Commission and the Spanish Ministry of Science Innovation and Universities (PRX19/00148) for a research stay at University of Hawaii at Manoa.

International audience; Late Cenozoic landscape evolution in intracratonic basins represents an illustrative example of the interaction between surface processes, climate, lithologic and tectonics factors. Here, we model the transition from endorheic to exorheic conditions for the intracratonic Madrid Basin (Tagus Basin, Central Spain). During the Late Cenozoic, this basin appears to have been the result of a prolonged period of similar to 4.0 Ma of headward erosion by the Atlantic external drainage system, local erosion and climatic oscillations. Determining the timing of this transition is crucial to understanding the principal mechanisms of the transition course of the intracratonic basins in or associated with pop-up ridges. We present a detailed geomorphic map of the north of the Tertiary Madrid basin and new age determinations of well-preserved pediments, alluvial fans, alluvial plains and strath terraces. By combining cosmogenic Be-10-Al-26-Ne-21 with magnetostratigraphic data, the sediments associated with the last endorheic phase yield an age of similar to 6.4 Ma. The earliest exorheic alluvial levels of the Madrid Cenozoic basin, explained here as the first fluvial terraces, have been dated through cosmogenic nuclides depth profiles (Be-10-Al-26) at 2.42 Ma and 2.36 Ma respectively.

The cave - site of Gran Dolina in Atapuerca preserves one of the most abundant records of Early to Middle Pleistocene sediments known so far. Therefore, establishing the chronology for the stratigraphic levels within the cavity is crucial. Since the early 1990s, subsequent excavations have allowed better access to the older stratigraphic levels TD4, TD5 and TD6 allowing for re-sampling with the aim of providing detailed chronology and testing whether the lithic industries-bearing layer TD4 has a post or pre-Jaramillo age, and hence establishing a better geochronological context for the lithic tools. In this study, we obtained negative magnetic polarity directions for these stratigraphic levels, a result consistent with previous studies that already identified the Matuyama—Brunhes boundary between TD7 and TD8 levels. In addition, several new ESR analysis, recently published, were carried out throughout the sequence, provide an age between 0.77 and 0.85 Ma for the upper limit of TD6 and an age of 0.91 ± 0.25 Ma for the lower limit of TD4. The age provided by ESR for TD6 is consistent with recent luminescence analysis, which provides a mean age of 846 ± 57 ka. The combination of ESR, luminescence, biostratigraphy, with our new paleomagnetic results, supports a post-Jaramillo age for layer TD4 in Gran Dolina.

This work focusses on the Sierra de Atapuerca Thinchera karst system, in which Gran Dolina and Galeria Complex sites are located. A total of eight ERT profiles were performed over an area that covers both sites, with the aim of identifying the dimensions and continuity of these passages. The interpretation of the 2D and 3D profiles has allowed determining the extension of the conduits as well as the presence of a filled entrance that might be common to both sites. With the aid of 2D modelling experiments it was also possible to resolve some of the hypothesis raised from the interpretation of the 2D pseudosections. All these data have ultimately lead to a better understanding of the karst and sites' formation process.

Deciphering the origin and depositional history of archaeological and paleontological deposits is fundamental to evaluate artifact and fossil contextualization. We present new rock magnetic data based on the anisotropy of magnetic susceptibility (AMS) that allow the fabric analysis and characterization of depositional modes in cave sediments. This approach was tested on both fossiliferous and sterile deposits for Gran Dolina and Galeria localities from the Atapuerca karstic complex (Spain). Our AMS approach has allowed to determine paleoenvironmental conditions in both sites, as well as to establish where a given sedimentary unit preserves primary depositional fabrics or has possible post-depositional perturbation. In this sense, it is worth emphasizing that even the sampled horizons that have hominid remains Gran Dolina show no signs of fabric disruption or evidence for massive transport of the sedimentary particles.

We used ground-penetrating radar (GPR) to identify a variety of karstic features in the archaeo-paleontological sites of the Sierra the Atapuerca (Burgos, Spain). The aim of this study was to discover the structure of the caves exposed in the 19th century by a railroad trench, specifically their bottom part, which remains covered under the railroad current surface. For this purpose, three GPR grids were made in the Trinchera area, next to the sites of the Sima del Elefante, the Galeria Complex and the Gran Dolina. The analysis of both the radar wave signatures and the radar amplitude reflections, together with the existing data on the caves, allowed for the definition of the location and geometry of different karstic features, including air-filled caves, sediment-filled caves and bedrock structures. Two mechanical boreholes drilled next to the sites also added the information on the stratigraphy of the bottom part of the caves and helped with the interpretations of the GPR survey. We could distinguish between the intact geological features and the areas that were altered by the railroad construction and the later quarrying activity.

East Africa has provided the earliest known evidence for Oldowan stone artifacts and hominin-induced stone tool cutmarks dated to ~2.6 million years (Ma) ago. The ~1.8-million-year-old stone artifacts from Ain Hanech (Algeria) were considered to represent the oldest archaeological materials in North Africa. Here we report older stone artifacts and cutmarked bones excavated from two nearby deposits at Ain Boucherit estimated to ~1.9 Ma ago, and the older to ~2.4 Ma ago. Hence, the Ain Boucherit evidence shows that ancestral hominins inhabited the Mediterranean fringe in northern Africa much earlier than previously thought. The evidence strongly argues for early dispersal of stone tool manufacture and use from East Africa or a possible multiple-origin scenario of stone technology in both East and North Africa., Support by grants from CNRPAH, MINECO (HAR2013-41351-P), The L.S.B. Leakey Foundation, the National Science Foundation (NSF-BCS-0517984), the Wenner-Gren Foundation (grants 7815 and 8323), the European Research Council (FP7-People-CIG2993581), and the Stone Age Institute (Bloomington, IN) to M.S.; MINECO (CGL2010-16821) to J.M.P. and M.D.; the Australian Research Council (Future Fellowship 150100215) to M.D.; and the European Science Foundation (Synthesys GB-TAF-4119 and DE-TAF-668) to J.v.d.M., CGL2015-65387-C3-1-P (MINECO/FEDER) to J.v.d.M. and I.C., and AGAUR (2017SGR1040) and URV (2017PFR-URV-B2-91) to I.C.

The Early-Middle Pleistocene transition (EMPT), also known as the “mid-Pleistocene revolution” or “mid-Pleistocene transition“ (∼1.4–∼0.4 Ma), has become a major research topic in the last few decades. Evidence recorded by numerous multidisciplinary studies indicates that changes in the Earth's orbital cyclicity during this time period strongly impacted both the marine and terrestrial realms, as borne out by a wide range of physical and biotic proxies (see overview in Head and Gibbard, 2005). This influence has been especially pronounced in the Northern hemisphere and particularly in Europe, where the EMPT demonstrably corresponds to significant changes in mammalian evolution and dispersals, including a major faunal turnover, the arrival of the genus Homo and important techno-cultural advances (e.g. Rook and Martinez-Navarro, 2010, Abbate and Sagri, 2012, Carbonell et al., 2015).

The palaeontological site of Huescar-1 contains a diverse faunal assemblage and has played an important role in establishing local-scale biozone successions in the Guadix-Baza basin. Here, we provide the first ages for the fossil-bearing deposits at this site using a suite of extended-range luminescence dating approaches, including optically stimulated luminescence (OSL) of quartz ‘supergrains’, multi-grain and single-grain thermally transferred OSL of quartz and post-infrared infrared stimulated luminescence of K-feldspars. Assessments of luminescence characteristics and laboratory quality assurance tests indicate that the Huescar-1 sediments are well-suited for extended-range dating applications, and the resultant chronologies obtained using different luminescence approaches display a high degree of consistency. Our combined luminescence ages reveal that the fossil-bearing fluvial sediments at this marginal lacustrine site were deposited ∼420–460 ka or possibly ∼420–570 ka, which is younger than some of the tentative late Early to early Middle Pleistocene ages inferred from faunal associations. Comparison of the dating results with taphonomic, taxonomic and geomorphic evidence suggests that the site may preserve an admixture of bones in primary depositional context and reworked fossils sourced from potentially older deposits in the surrounding valley. As such, the luminescence ages obtained for the host sediments may not be contemporaneous with all of the faunal remains preserved at Huescar-1.

Sediments of the Plio-Pleistocene Guadix – Baza basin have provided a wealth of information on the first hominin populations in Western Europe. To better constrain the age of the Fuente Nueva-3 archaeological site within the basin, and to complement previous magnetostratigraphic studies, two vertical boreholes were taken that provide a continuous record of the lower part of the sequence. Results indicate that the sequence is dominated by negative inclinations, but some additional intervals with positive inclination are also identified in the lower part of the sequence. A new cosmogenic nuclide burial age of 1.50 ± 0.31 Ma helps constrain the magnetostratigraphic record. The abundance of normal polarity directions at the bottom of a borehole may indicate proximity to the Olduvai Subchron; however, further analyses are required to confirm this hypothesis.

Based on a combination of Electron Spin Resonance (ESR) dating of quartz, luminescence dating of K-feldspar and palaeomagnetism, this study presents the first chronostratigraphic framework for the Pleistocene fluvial deposits of the lower Moulouya river in the Triffa basin (NE Morocco). K-feldspar pIRIR225 and pIRIR290 signals of all samples are saturated, suggesting fluvial deposition at least as early as the Middle Pleistocene (∼0.39–0.80 Ma). Consequently, further chronological information was obtained with ESR dating of quartz grains from the ancient Pleistocene fluvial deposits. As for ESR, the multiple centres approach provides equivalent dose values derived from the Al and Ti centres that mostly agree within 1σ-error, suggesting complete signal resetting from the former during fluvial transport. ESR dating results yield Calabrian deposition ages for all river profiles from ∼1.1 to ∼1.5 Ma. These ages are remarkably consistent with the palaeomagnetic results: the occurrence of mostly reversed polarity in the deposits indicates a Matuyama age (>0.78 Ma). While low incision rates in the Triffa basin (0.025 ± 0.003 mm/a) related to thrusting activity during the Calabrian could be inferred, the fluvial record points to an acyclic and discontinuous sedimentation pattern over the last ∼1.3 Ma. It thereby probably rules out climate as the main driver for fluvial aggradation in the lowermost sedimentary basin. At a regional scale, several indicators point to transient fluvial response resulting from major Quaternary tectonic activity along the Beni Snassen gorge, located directly upstream of the investigated basin. We suggest that a capture event at the margin of the uplifting Beni Snassen massif occurred between 1.04 and 1.36 Ma at the latest and subsequently led to the creation of the gorge.

El karst de la Sierra de Atapuerca representa un interesante sistema multinivel, inactivo y heredado de antiguos niveles de base plio-pleistocenos, que alberga los enclaves prehistóricos más importantes para el conocimiento del poblamiento antiguo en Eurasia, y que fue declarado Patrimonio de la Humanidad en 2000 por la UNESCO. Estas cuevas se originan a partir de conductos subhorizontales con paleodrenajes en sentido SN, localizándose la zona de descarga en la cabecera del río Pico. Los conductos están organizados en tres niveles principales que aparecen colgados entre 90 y 60 m sobre el actual cauce del río Arlanzón, coincidiendo con los niveles de base generados por sus terrazas fluviales T2, T3 y T5. La incisión fluvial liberó de las aguas los conductos superiores mientras se excavaban los niveles inferiores del karst. Las cuevas que iban quedando accesibles fueron utilizadas por la fauna y los homininos, conservando un registro arqueo-paleontológico de más de 1,2 Ma.

The present study reports the results of the first direct Electron Spin Resonance (ESR) dating study of Homo antecessor, the oldest known hominin species identified in Western Europe. The analysis of a tooth (ATD6-92) from TD6 unit of Atapuerca Gran Dolina (Spain) following a “semi non-destructive” procedure provides a final age estimate ranging from 624 to 949 ka, which covers all possible uranium uptake scenarios. Last, the additional magnetostratigraphic data collected within TD6 enables to further constrain the initial ESR chronology and to propose an age of between 772 and 949 ka for Homo antecessor, in agreement with previous dating works. Although our new results do not refine the existing chronology of TD6 unit, they nevertheless support the antiquity of H. antecessor, which pre-dates the estimated divergence age of modern and archaic human lineages based on genetic evidence. This work illustrates the challenges of dating human teeth by means of the ESR method, with the main pitfalls that are sometimes inherent to this specific application (e.g., systematic μCT-scanning of fossil hominin teeth; limited knowledge about the original sedimentary environment for teeth coming from old excavations; heterogeneous spatial distribution of the U-series elements in dental tissues). We identified several sources of uncertainty that may directly impact the accuracy of the age result. In particular, a slight contamination of dentine (

The sedimentary record in the Guadix-Baza Basin (southern Spain) has proved to be a great source of information for the Miocene through the Pleistocene periods, due to the abundant faunal remains preserved, in some cases associated with lithic tools. The Solana del Zamborino (SZ) section has been the subject of controversy ever since a magnetostratigraphic analysis resulted in an age of 750–770 Kyr for Acheulean tools, a chronology significantly older than the ~600 Kyr established chronology for the first Acheulean record in Europe. Although recent findings at the “Barranc de la Boella” site (north-east of the Iberian Peninsula) seem to indicate that an earlier introduction of such technique in Europe around 0.96–0.781 Ma is possible, the precise age of the classical site at SZ is still controversial. The aim of this paper is to constrain the chronology of the site by developing a longer magnetostratigraphic record. For this purpose, we carried out an exhaustive sampling in a new succession at SZ. Our results provide a ~65 m magnetostratigraphic record in which 4 magnetozones of normal polarity are found. Our new magnetostratigraphic data suggest an age range between 300–480 Kyr for the lithic tools, closer to the age of traditional Acheulean sites in Europe.

The question of the earliest hominid settlements in northern Africa has been under debate for a number of years due to the lack of precise chronologies. Here we present new paleomagnetic data that supports an Olduvai Subchron age for the archaeological sites at Ain Hanech and El-Kherba, in northern Algeria. Our study is based on a 22 m-thick magnetostratigraphy of the Ain Hanech Formation, which includes contextualized Oldowan and Acheulian lithic tools. Characteristic remanent magnetization directions were obtained from both thermal and alternating field demagnetization procedures of specimens from twenty five sampled horizons. Our results reveal the presence of the Olduvai Subchron in the upper part of the stratigraphic section, constraining the age of these important archaeological sites in northern Africa.

We evaluate the application and significance of Low-Temperature Anisotropy of Magnetic Susceptibility (LT-AMS) measurements in deformed mudrocks. Originally conceived as a way to enhance paramagnetic relative to ferromagnetic susceptibility, LT-AMS studies offer significant potential in constraining the coexistence of subfabrics that are due to phyllosilicate grains with different preferred orientations. In this study we report a detailed procedure to obtain such directional susceptibilities, measuring samples in multiple orientations at liquid nitrogen temperatures in order to determine the LT-AMS. Due to unequal changes of magnetic susceptibility in micas at low-temperature, the enhancement of standard AMS at low-temperature better separates interacting fabrics in natural rocks, particularly depositional fabrics versus deformational fabrics. LT-AMS is a non-destructive technique that readily offers an ability to separate ferromagnetic and paramagnetic fabrics, and allows the characterization and quantification of multiple fabrics in natural rocks.

We use a combination of rock magnetism (anisotropy of magnetic susceptibility, AMS) and magnetic polarity to characterize cave deposits and as a proxy for sedimentary fabric. In three localities at the Atapuerca archaeological site (Galeria, Gran Dolina and Sala de los Ciclopes), magnetic foliation (K max /K int ) is always greater than lineation (K int /K min ), consistent with a primary, depositional, sedimentary fabric. Our results, although preliminary, reveal a higher degree of anisotropy in autochtonous deposits compared to allochthonous deposits, possibly indicative of a higher hydrodynamic regime in the former. At two localities the magnetic lineation (K max ) defines a cluster which is thought to be antipodal to the palaeocurrent direction. Hence we are able to retrieve palaeoflow directions in deposits that otherwise lack any other sedimentary structure. We conclude that AMS is a powerful tool for determining the hydrodynamic character of depositional environments in cave sediments at the Atapuerca archaeological site. A better understanding of the depositional environment and how sedimentation occurred allows reconstruction of the karst evolution and ultimately a better definition of human interaction with the environment.

The so-called “Gran Dolina site” (Atapuerca mountain range, N Spain) is a karstic cavity filled by sediments during the Pleistocene, some of which contain a rich ensemble of archaeological and paleontological records. These sediments have contributed significantly to our understanding of early human dispersal in Europe but, in contrast, older, interior facies deposits have received much less of attention. The stratigraphy of Gran Dolina reveals an abrupt sedimentary change of interior to entrance facies from bottom to top, reflecting a significant paleoenvironmental change that promoted the accumulation of sediments transported from the vicinity of the cave by water or “en masse”. Since the major magnetic polarity reversal known as the Matuyama-Brunhes boundary (0.78 Ma) was detected within the TD7 unit in the middle of the stratigraphic section, we carried out a new combined paleomagnetic, radiometric (U-Pb), and electron spin resonance (ESR) dating study of the lower part of the sequence in order to constrain the chronology of the interior facies at Gran Dolina. U-Pb analysis of speleothems did not produce age information as the samples proved to be extremely unradiogenic. The magnetic stratigraphy of the cave interior sediments reveals a dominant reverse magnetic polarity, coherent with a Matuyama age, and interrupted by a normal polarity magnetozone interpreted as the Jaramillo Subchron (1.0–1.1 Ma). ESR ages on quartz grains from the upper part of the interior facies sediments are coherent with such an interpretation. We conclude that the fluvial deposits (interior facies) that constitute the cave floor began accumulating before 1.2 Ma. The development of large cave entrances at Gran Dolina occurred shortly after the Jaramillo Subchron but before ca 900 ka ago.

The archaeological karstic infill site of Galería Complex, located within the Atapuerca system (Spain), has produced a large faunal and archaeological record (Homo sp. aff. heidelbergensis fossils and Mode II lithic artefacts) belonging to the Middle Pleistocene. Extended-range luminescence dating techniques, namely post-infrared infrared stimulated luminescence (pIR-IR) dating of K-feldspars and thermally transferred optically stimulated luminescence (TT-OSL) dating of individual quartz grains, were applied to fossil-bearing sediments at Galería. The luminescence dating results are in good agreement with published chronologies derived using alternative radiometric dating methods (i.e., ESR and U-series dating of bracketing speleothems and combined ESR/U-series dating of herbivore teeth), as well as biochronology and palaeoenvironmental reconstructions inferred from proxy records (e.g., pollen data). For the majority of samples dated, however, the new luminescence ages are significantly (∼50%) younger than previously published polymineral thermoluminescence (TL) chronologies, suggesting that the latter may have overestimated the true burial age of the Galería deposits. The luminescence ages obtained indicate that the top of the basal sterile sands (GIb) at Galería have an age of up to ∼370 thousand years (ka), while the lowermost sub-unit containing Mode II Acheulean lithics (base of unit GIIa) was deposited during MIS 9 (mean age = 313±14 ka; n = 4). The overlying units GIIb-GIV, which contain the richest archaeopalaeontological remains, were deposited during late MIS 8 or early MIS 7 (∼240 ka). Galería Complex may be correlative with other Middle Pleistocene sites from Atapuerca, such as Gran Dolina level TD10 and unit TE19 from Sima del Elefante, but the lowermost archaeological horizons are ∼100 ka younger than the hominin-bearing clay breccias at the Sima de los Huesos site. Our results suggest that both pIR-IR and single-grain TT-OSL dating are suitable for resolving Middle Pleistocene chronologies for the Sierra de Atapuerca karstic infill sequences.

The late Pliocene shallow lacustrine sequences in the Guadix-Baza basin (Betic Ranges, southeast Spain) are a suitable setting for mammal chronology because of the abundance of rich, mammal-bearing sites. Stratigraphic superposition of late Ruscinian and Villanyian vertebrate fossils makes the Galera Section very appropriate for magnetostratigraphic dating. Sediments are characterized by a weak but measurable magnetization predominantly carried by magnetite. Other remanence carriers, such as iron sulphides and hematite, may be significant only in some particular lithologies, such as dark palustrine organic silts and red alluvial beds, respectively. Direct correlation of the Galera Section to the geomagnetic polarity time scale provides a reliable dating of the late Ruscinian and Villanyian mammal units. The Ruscinian/Villanyian boundary (MN15/MN16) is found to occur in the lower Gauss chron, and approximately correlates to the 3.3 Ma cooling event observed in stable-isotope and planktonic foraminifera deep sea records. The earliest occurrence of late Villanyian assemblages (MN17) in the lower part of the Matuyama chron allows dating of the early/late Villanyian boundary (MN6/MN17) to approximately 2.4–2.6 Ma. Based on the presence of late Villanyian assemblages underlying the base of the Olduvai chron, a maximum age of 1.95 Ma (top of C2r) is attributed to the Villanyian/Biharian (MN17/MmQ) boundary. A 300 kyr sedimentary gap in the Galera Section is suggested to correlate with a probable early Villanyian hiatus, an hypothesis that agrees with the absence of fossils of this age elsewherein the Baza Formation.

New biostratigraphic data and paleomagnetic analysis of the site of Can Llobateres (Northeastern Spain) allows an age-estimation of 9.6 Ma for the recently discoveredDryopithecus laietanusfacial remains (CLl-18000) and 9.7 Ma for the earlier hominoid finds from this locality. This is an unexpectedly young age for such a primitive form, which can be accurately correlated with some of the finds of youngestSivapithecusin the Siwaliks. According to the phylogenetic model proposed here,Dryopithecusdisplayed a long period (some 5 Ma) of morphological stasis in Europe, which could be related to the preservation of subtropical forest conditions in the Western Mediterranean. In other parts of Southern Eurasia (Eastern Mediterranean and Siwaliks), quick vicarious evolution led to the diversification of thick-enamelled hominoids between 14 Ma and 12 Ma.

The evolution of the Torcas cave system (Sierra de Atapuerca) is analysed in order to shed light on the formation of the Atapuerca archaeological sites and human occupation in the area, critical for identifying the paths of the first human dispersal into Europe. The geomorphological analysis of the endokarst system and the regional base levels has revealed a multilevel cave system, with drainage directions from south to north, where old karst springs fed the Pico River. Using morphological and topographic evidence we have correlated the fluvial terraces situated at relative heights of + 84–80 m and + 78–70 m above the Arlanzon River (main course), with the first and second cave levels, respectively, both of Early Pleistocene age. The fluvial levels T4 (+ 60–67 m) and T5 (+ 50–54 m) are linked with the third level (Early–Middle Pleistocene), which contains fluvial deposits probably related to terrace T6 (+ 44–46 m). Progressive fluvial incision allowed humans to gain access to the cave system through several entrances from ~ 1.22 Myr until the end of the Middle Pleistocene, when these cave entrances became filled, forming the most interesting hominid-bearing deposits in Europe.

The eastern Galicia magnetic anomaly (EGMA) shows intensities up to 190 nT and is one of the major features of the magnetic field in northwestern Spain. Taking into account the seismic refraction and surface geological data, a 2.5D model of the magnetic properties of the crust in the area of the EGMA has been carried out. Models show that the anomaly can be produced by a middle to lower crustal layer a few kilometers thick with magnetic susceptibility of approximately 0.045 SI emplaced with a ramp-flat-like geometry in higher crustal levels and giving rise to horizontal displacements of about 50 km on the basal eastern Galicia thrust. This structure is in close agreement with surface geology, since the culmination of the Lugo dome and the extensional Viveiro fault can be interpreted in relation with the displacement along the eastern Galicia thrust. The southern termination of the EGMA can be related to the termination of the anomalous layer on a lateral hanging-wall ramp of this thrust. Rocks in the magnetic layer are interpreted as mainly lower crust mafic and / or ultramafic rocks. In the northern sector, at least part of the anomaly must be attributed to ultramafic Hercynian intrusives cropping out in the vicinity of the Viveiro fault.

The application of the progressive thermal demagnetization procedure of volcanic rock debris has been frequently used to determine the emplacement temperatures of pyroclastic deposits and thus to characterize the nature of these volcanic deposits. This debris consists of a mixture of juvenile fragments derived from the explosive fragmentation of erupting magma and an assortment of lithic clasts derived mainly from the walls of a volcanic conduit, as well as from the ground. The temperature at which the clasts were deposited can be estimated by analyzing its remanent magnetization. To do this, oriented samples of clasts are subjected to progressive thermal demagnetization and the directions of the resulting remanent vectors provide the necessary information. Clasts of basalt, andesite, limestone, pumice and homebricks have previously been used to estimate the emplacement temperatures of pyroclastic deposits. According to our data, clasts of red sandstones also seem to be good carriers of thermoremanent magnetization. We have carried out a paleomagnetic study on a Quaternary, lithic-rich, massive, pyroclastic deposit from the Puig d'Adri volcano (Catalan Volcanic Zone), which contains a large number of red sandstone clasts. It is concluded that the studied deposit cannot be considered as a lahar or as a pyroclastic surge deposit, considering both the emplacement temperature and the morphological features.

Reliable palaeomagnetic data from the emerged margins of the Valencia trough include results from Triassic, Jurassic, Paleogene and Miocene rocks. From these data, a clockwise rotation of the Catalan Coastal ranges relative to the western part of Iberia is apparent. In addition, a clockwise rotation is indicated by the magnetic directions from the Balearics with respect to those of the Catalan margin. Major Neogene structures in the evolution of the Valencia trough and thin-skinned tectonics rather than crustal-scale block motions play a large role throughout the Balearic Islands.

Cleavage-fissility perpendicular to bedding is a common feature in the external part of fold-and-thrust belts. Three techniques were used to determine the internal distortion in the frontal Southern Pyrenees: the analysis of strain markers such as burrows and rain drops, the measurement of fissility, and the measurement of anisotropy of magnetic susceptibility (AMS). The comparison of the three techniques showed a good fit although they differ in sensitivity to penetrative strain variations in the range of deformation values explored in the study case. On the regional scale, the values of layer parallel shortening (LPS) derived from the markers analysis are very constant and account for 16-23% of shortening. These values are two to three times larger than the shortening values calculated from the restoration of the macroscopic scale structures and indicate a good decoupling above the Cardona salt Formation. This study permitted an accurate restoration of the low-amplitude el Guix detached anticline. © 2003 Elsevier B.V. All rights reserved., This work has been partially financed by ElfAquitaine Production and Grups de Recerca Consol-idats (II Pla de Recerca de Catalunya) Project 2001SGR 00339. We would like to thank Iberpotash forgiving permission to access the railway outcrop andJordi Bayona and Ester Sans for their technicalsupport in the field scaling of the detailed outcrop.Jordi Corbera processed the outcrop image. TheServeis Cientificote`cnics de la Universitat de Barce-lona developed the IMAT program. We are alsograteful to David Durney who developed the fissilityprograms and with whom we have had constructivediscussions in the field. J.M. Casas and J.A. Mun ̃ozhelped us in the data processing and in improving themanuscript. We also want to thank R. Groshong, M.Rowan and K. McClay for their fruitful comments onthe paper as well as to G. Mitra and an anonymousreviewer for the helpful comments on the final versionof the manuscript.

The study of a late Oligocene-early Miocene, 300 m thick section of alluvial and shallow lacustrine sediments in the Ebro Basin, has allowed a high-resolution magnetic polarity stratigraphy for the Oligocene-Miocene boundary to be established. The samples studied include alluvial sandstones and mudstones as well as shallow lacustrine and paludine, micritic and microsparitic limestones. Two-hundred-and-fifty specimens were stepwise thermally or magnetically demagnetized following standard procedures. Magnetic imprints of the distinct lithologies present sharp contrasts, especially for the stability of the secondary components. The VGP data show 18 reversal events, defining a sequence of 16 polarity intervals. Lateral and vertical continuity of the sequences studied has enabled a correspondence between the local paleomastological biozones and the magnetostratigraphic succession to be established. The high-resolution chronology of this magnetostratigraphic succession provides valuable information that allows the non-marine European biochronological scales to be correlated to the global polarity time scale (GPTS). The magnetic polarity zonation of the section has been correlated to the GPTS using the distinct sequence and pattern polarity reversals as well as by considering the fossil mammal assemblages. As a preliminary result, chrons 8, 7A, 7 and 6C have been identified. © 1994.

The magnetic polarity stratigraphy from a lacustrine sequence of the Baza Basin (Betic Chain, Southern Spain) has been interpreted as having a Lower Pleistocene age. Fifty-nine paleomagnetic sites have been obtained and a set of 179 specimens has been demagnetized with both thermal and alternating field procedures. Several magnetic parameters, that depend on the lithology, have been obtained. The characteristic remanent magnetization polarity has been unambiguously recovered over the whole sequence. The materials studied span chron 1r.2, located in the upper Matuyama epoch. This allows the placement of the faunas studied, ranging from the Late Villanyian to the Late Biharian, in the magnetic polarity time scale (MPTS). This work also proves that magnetostratigraphy can be established in lacustrine sediments even with extremely low magnetic intensities. © 1994.

The magnetobiochronological dating of the late Miocene hipparionine horses ( “Hipparion” ) in the western Mediterranean places its first appearance datum (FAD) in the circum-Mediterranean region at the Chron C5r, at a minimum age of 11.1 Ma. This date challenges some of the widely accepted datings of this bioevent in western Eurasia and is relevant to the discussion of the mode and tempo of “Hipparion” dispersal. The migration of the “Hipparion” North American ancestor is related to the glacioeustatic sea-level lowstand of the supercycle TB3.1 (early Tortonian) and to the concurrent deep-sea hiatus NH4 and oceanic δ 18 O isotopic event Mi5. The “Hipparion” dispersal was a conspicuous, worldwide, on-land bioevent that was coeval with major late Miocene oceanic and high-latitude paleoclimatic global changes.