Estratigrafía y sedimentología del yacimiento de Gran Dolina (Sierra de Atapuerca, Burgos)

Gran Dolina es uno de los yacimientos arqueológicos y paleontológicos más importantes del Pleistoceno medio e inferior en Europa. Consiste en una cueva de 24 m de altura, rellena de sedimentos que contienen restos arqueológicos, perteneciente al karst de la Sierra de Atapuerca. En la presente tesis doctoral se ha realizado una descripción de los niveles sedimentarios de Gran Dolina, identificando 108 niveles sedimentarios agrupados en 27 subniveles y 12 unidades litoestratigráficas. Estos están formados por 21 facies sedimentarias diferentes, que se han dividido en dos grandes grupos: facies de interior y facies de exterior. Las facies de interior se han dividido, a su vez, en facies químicas y facies detríticas, mientras que las facies de exterior se han separado en facies de flujos de gravedad y facies fluviales. La entrada de los sedimentos del exterior se produce por tres entradas principales y varias entradas secundarias, como fisuras y grietas

Assessing the influence of isotopic composition of water on that of clay minerals during chemical treatments.

The isotopic composition of hydrogen in authigenic minerals is a useful tool to reconstruct past paleo-environments. Clay minerals are an important component of authigenic minerals in soils and sediments but they usually occur with other compounds that must be eliminated before the analysis, such as organic matter and carbonates. Thus, various “pre-treatments” are used, generally involving dilute HCl and H2O2 solutions in water. In this work, the influence of the isotopic composition of the water used in these pre-treatment solutions is assessed, using ten different samples of clay minerals. The isotopic composition of hydrogen was measured in each sample after HCl pre-treatment alone, H2O2 pre-treatment alone and both HCl and H2O2 pre-treatments in sequence, using two types of water in the pre-treatment solutions: one 2H-enriched and one 2H-depleted. The results indicate some influence of the isotopic composition of the water on the clay minerals after pre-treatment. In general, the samples showed significant alteration by HCl pre-treatment and negligible alteration by H2O2 pre-treatment. A pure kaolinite reference material did not show any change by chemical pre-treatment while a smectite reference material did show significant effects. Other samples (Ethiopian lacustrine sediment samples and Spanish cave sediments) showed important differences, which also depend on clay mineralogy. Thus, mineralogy seems to be the main cause of the variability in the alteration, especially the quantity of smectite. In addition, this result challenges the utility of clay minerals for isotope studies in acid conditions, such as in acidic soils, to reconstruct past environments and, therefore, climate changes.This study was developed during a stay supported by predoctoral mobility grant from the Spanish MINECO. Financial support for this work was obtained from MINECO Grant CGL2015-65387-C3-3-P. I. Campaña was the beneficiary of a predoctoral FPI Grant from the Spanish MINECO. We thank Jessica Wilson at the University of South Florida School of Geosciences who supported the isotopic analysis. J.G. Wynn was supported by an NSF IR/D program. Special thanks to the local resident of Burgos that help us remove the car from a mud puddle. // Funding for open access charge: Universidad de Málaga / CBU

Revision of TD1 and TD2 stratigraphic sequence of Gran Dolina cave (Sierra de Atapuerca, Spain)

Gran Dolina es una cueva rellena por al menos 25 m de sedimentos pleistocenos dividido en 12 unidades litoestratigráficas y 19 facies sedimentarias. Estas facies sedimentarias se han dividido entre facies alóctonas, definidas como entradas de sedimentos desde el exterior, y facies autóctonas, definidas como sedimentos generadas dentro del karst; sin embargo, esta clasificación de facies ha sido cuestionada en trabajos recientes. En este estudio se ha descrito en detalle las unidades TD1 y TD2 de Gran Dolina y se ha evaluado la idoneidad del uso de facies autóctonas. Para ello, se ha estudiado la sección estratigráfica de la excavación arqueológica, combinando observaciones de campo con análisis de laboratorio (tamizado, difracción láser y DRX) para caracterizar la textura y estructura de los sedimentos. A partir de estos estudios, se han identificado un total de 8 facies sedimentarias, y se han separado la unidad TD1 en dos sub-unidades y 13 niveles, y la unidad TD2 en tres sub-unidades. La asociación de facies indica una sucesión de fases freáticas y vadosas que definiría conjuntamente condiciones epifreáticas en el interior de la cueva, relacionadas con la transición entre la terraza T3 y la terraza T4 del valle del río Arlanzón. Por tanto, se propone el término facies de interior (y facies de entrada en vez de facies alóctonas) para definir los sedimentos de las unidades de TD1 y TD2 de Gran Dolina, ya que el análisis de facies indica transporte de los sedimentos por corrientes subterráneas.This study was supported by the project PGC2018-093925-B-C31 of the Spanish Ministry of Science and Innovation, Spanish State Research Agency and FEDER funds from the UE. Project PID2021-122355NB-C33 financed by MCIN/AEI/10.13039/501100011033/FEDER, UE. Funding for open access charge: Universidad de Málaga/CBUA. I. Campaña is the beneficiary of a postdoctoral grant from Junta de Andalucía. This work has benefited from discussion with Mathieu Duval, Lucía Bermejo, Lucía Ojeda and Sergio Durán. The constructive comments made by one anonymous reviewer and Dr. Ivan Martini contributed to improve the manuscript

Reconstructing depositional environments through cave interior facies: The case of Galería Complex (Sierra de Atapuerca, Spain)

This work showed that cave sediments are useful for geomorphologic studies and for reconstructing depositional environments. While the cave entrance facies have been extensively studied for their relationship with the fossil and archaeological record, the cave interior facies have received much less attention, although they can provide much information on the geomorphological evolution of the karst. This work presents the stratigraphic and sedimentological study of a section >6 m thick and 10 m long of cave interior sediments of Galería Complex (Sierra de Atapuerca, Spain). Galería Complex is a cavity infill of the Sierra de Atapuerca (Spain), composed of three sections filled by at least 30 m of Pleistocene sediments. This sequence is divided into 5 lithostratigraphic units named from bottom to top: GI – GV. GI unit is 19 m thick of interior facies in the base of the Galería Complex, divided into two sub-unit, GIa and GIb, by the Matuyama-Bruhnes paleomagnetic boundary. GI unit shows an issue with the chronology since has uncoherent between TT-OSL and ESR/U-series and paleomagnetism dates. This work has been done by combining field observation with laboratory sedimentary analysis to characterize the texture and structure of the sediments. Based on these studies, 12 layers and 9 sedimentary facies have been identified. The facies associations indicate a clear separation between GIa and GIb sub-units. GIa sub-unit is dominated by epiphreatic conditions and represents continuous relativity sedimentation during the Early Pleistocene; meanwhile, GIb shows important erosion events and facies with reworked materials that indicate vadose conditions during the Middle Pleistocene. This environmental change is related to the geomorphological evolution of the Arlanzón River. In addition, soft-sediment deformation structures have been described, including faults and low-angle folds...Funding for open access charge: Universidad de Málaga / CBU

Plio-Pleistocene hydrothermal events of the Baza Basin (Betic Cordillera, SE Spain) and their paleoecological implications

Los rellenos continentales sedimentarios de edad Plioceno inferior a finales del Pleistoceno medio en la cuenca de Baza (depresión de Guadix-Baza, SE de España) son mundialmente conocidos por su elevado grado de completitud estratigráfica y la excepcional conservación de su registro fósil de vertebrados terrestres. Estos sedimentos se depositaron en ambientes fluvio-lacustres y conservan abundantes asociaciones de restos de grandes mamíferos, incluyendo las evidencias más arcaicas de presencia humana en Europa occidental, ubicadas en los yacimientos de finales del Pleistoceno inferior de Barranco León y Fuente Nueva-3, datados ambos en ∼1,4 Ma. Desde finales del Mioceno, la cuenca se vio sometida a intensa actividad tectónica, mostrando depósitos originados en antiguas surgencias de aguas termales. Estas surgencias se desarrollaron a lo largo de una amplia malla espacio-temporal, ligada a fracturas tectónicas, mostrando mayor concentración en la subcuenca de Orce desde el Plioceno superior al Holoceno. El análisis de la composición de las silexitas y otras facies asociadas a estas fuentes termales muestra la presencia de marcadores geoquímicos y mineralógicos ligados a escenarios hidrotermales. El aporte continuado de las fuentes termales en la cuenca de Baza dio como resultado biotopos muy ricos y productivos, capaces de soportar una elevada diversidad y biomasa de mamíferos terrestres. Ambientes geológicos, hidroquímicos y ecológicos similares se encuentran alineados con surgencias termales en África oriental, el Corredor Levantino y el área circum- mediterránea. Proponemos como hipótesis que la presencia de tales corredores hidrotermales favoreció la dispersión de los homininos y otros grandes mamíferos durante el Plio-Pleistoceno, dando lugar a la primera colonización humana de Europa.Funding for open access charge: Universidad de Málaga / CBUA. This work was supported by Consejería de Economía, Innovación, Ciencia y Empleo,Junta de Andalucía, EXP: BC.03.174/19 10153, M. Patrocinio Espigares, Research Groups RNM-146, Paul Palmqvist, RNM-199, Paul Palmqvist,UMA18-FEDERJA-188, M. Patrocinio Espigares, PAIDI 2020 postdoctoral grant, Isidoro Campaña, Generalitat de Catalunya, 2021SGR 01238 (AGAUR), Bienvenido Martínez-Navarro, Comunidad de Madrid, Programa de Atracción de Talento, Guillermo Rodríguez-Gómez, Ministerio de Ciencia e Innovación, CEX2019-000945-M, Bienvenido Martínez-Navarro

Sharing food with hyenas: a latrine of Pachycrocuta brevirostris in the Early Pleistocene assemblage of Fuente Nueva-3 (Orce, Baza Basin, SE Spain)

The Early Pleistocene archeological site of Fuente Nueva-3 (FN3) preserves some of the oldest evidence of hominin presence in Western Europe, including a huge assemblage of Oldowan tools and evidence of butchering and marrow processing of large mammal bones. Moreover, there is also evidence of the regular presence of carnivores at the site, including a small proportion of bones that show tooth marks, the majority of which can be attributed to the giant, short-faced hyena Pachycrocuta brevirostris, and there are 220 coprolites, most of them from the Upper Archeological Level. In order to identify the defecating agent, we analyze here the coprolites and compare them with other specimens from the literature and with scats from zoo spotted hyenas (Crocuta crocuta). The morphology, color, size, and chemical composition of the FN3 coprolites allow us to attribute them to the hyena P. brevirostris, which is also represented at the site by fossil specimens. In addition, we evaluate the origin of the accumulation of coprolites and discuss on the role played by the scavenging hyenas in the accumulation and modification of the bone remains unearthed at the site, which allows evaluating the contribution of the giant hyena to this Early Pleistocene site. Finally, based on the lithology of layer 5 of the Upper Archeological Level, fine sands and clays deposited in a salt-lake environment, we hypothesize that this layer may have acted as a quicksand where large-sized animals like elephants were trapped and their carcasses lured scavenging carnivores.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEJunta de AndalucíaGeneralitat de CatalunyaMinisterio de Ciencia e InnovaciónComunidad de Madridpu

The late Early Pleistocene site of Fuente Nueva-3 (Guadix-Baza Depression, SE Spain): a hyena latrine developed on a quicksand trap for megaherbivores?

The late Early Pleistocene archaeological site of Fuente Nueva-3 (FN3), which lies in the Guadix-Baza Depression (SE Spain) and is dated to ~ 1.4 Ma, contributes some of the oldest evidence of hominin presence in Western Europe, including a huge tool assemblage of Oldowan tradition, manuports (i.e., unmodified stones used as percussion tools) and abundant fossils of large mammals, some of which preserve anthropogenic marks related to defleshing, butchering and marrow processing. In addition, there are bones with tooth marks produced by scavenging carnivores. The fertile layers of the FN3 section have been grouped in a lower archaeological level (LAL) and an upper archaeological level (UAL). Both levels preserve abundant skeletal remains and lithic tools. However, the LAL shows a high density of manuports, which suggests that hominin activity was more intense at this level, while the UAL preserves many remains of megaherbivores, particularly proboscideans (Mammuthus meridionalis), and almost all coprolites unearthed from the site, which points to a greater involvement of the giant hyenas (Pachycrocuta brevirostris). In this paper, we (i) test for statistical differences in the composition of the faunal assemblages preserved in the UAL and LAL; and (ii) analyze particle size in the fertile layers of both archaeological levels. Our results show that megaherbivores are comparatively overrepresented in the UAL, specially by young elephants, while other medium-to-large and large-sized ungulates, particularly equids, are more abundant in the LAL, showing a predominance of adult individualsFounding for open access charge: Universidad de Málaga / CBU

New interpretation of the Gran Dolina-TD6 bearing Homo antecessor deposits through sedimentological analysis

Gran Dolina is a cavity infilled by at least 25m of Pleistocene sediments.This sequence contains the TD6 stratigraphic unit, whose records include around 170 hominin bones that have allowed the definition of a new species, Homo antecessor. This fossil accumulation was studied as a single assemblage and interpreted as a succession of several human home bases. We propose a complete stratigraphic context and sedimentological interpretation for TD6, analyzing the relationships between the sedimentary facies, the clasts and archaeo-palaeontological remains. The TD6 unit has been divided into three subunits and 13 layers. Nine sedimentary facies have been defined. Hominin remains appear related to three different sedimentary facies: debris flow facies, channel facies and floodplain facies. They show three kinds of distribution: first a group of scattered fossils, then a group with layers of fossils in fluvial facies, and third a group with a layer of fossils in mixed fluvial and gravity flow facies. The results of this work suggest that some of these hominin remains accumulated in the cave by geological processes, coming from the adjacent slope above the cave or the cave entry, as the palaeogeography and sedimentary characteristics of these allochthonous facies suggest

The first direct ESR dating of a hominin tooth from Atapuerca Gran Dolina TD-6 (Spain) supports the antiquity of Homo antecessor

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 (<6%) in the enamel fragment measured by ESR was found to induce a significant age underestimation (33%) if not taken into consideration. It indeed caused not only a DE underestimation (by about 8%), but also produced a massive internal dose rate overestimation (by a factor of about 3.5). In contrast, other sources of uncertainty, such as the heterogeneity of the sedimentary environment, the variability of the water content over time, the previous μCT-scanning of the tooth or the potential preferential creation of unstable NOCORs in the ESR signal, showed here a limited impact on the final age result. Given our current understanding of the ESR method and the existing uncertainties associated with the evaluation of the DE and dose rate, this is probably as far as we can presently go in the dating study of ATD6-92 sample

Conceptos básicos y métodos en geoarqueología : geomorfología, estratigrafía y sedimentología

En este trabajo se sintetizan los conceptos y métodos básicos de tres de las ciencias más comunes en geoarqueología, como son la geomorfología, la estratigrafía y la sedimentología. A través de estas ciencias se trata de reconstruir los paisajes y los procesos de formación en torno a las ocupaciones humanas del registro arqueológico. Las distintas metodologías son de diversa naturaleza y escala, combinando técnicas cartográficas, principios geológicos, descripciones de campo y análisis de laboratorio para caracterizar los materiales y medios físicos asociados a las ocupaciones humanas.En aquest treball se sintetitzen els conceptes i mètodes basics de tres de les ciències més comunes en geoarqueologia, com són la geomorfologia, l'estratigrafia i la sedimentologia. A través d'aquestes ciències es tracta de reconstruir els paisatges i els processos de formació al voltant de les ocupacions humanes del registre arqueològic. Les diferents metodologies són de diversa natura i escala, i combinen tècniques, principis geològics, descripcions de camp i anàlisis de laboratori per caracteritzar els materials i medis físics associats a les ocupacions humans.In this paper, the basic concepts and methods of three of the most common sciences in Geoarchaeology (Geomorphology, Stratigraphy and Sedimentology) are summarized. Using these sciences, the landscape and the formation processes associated with the archaeological occupations are reconstructed. The different methodologies are diverse in nature and scale, combining mapping techniques, geological principles, field descriptions and laboratory analysis, in order to characterize the materials and physical environments related to archaeological sites