Tracing environmental and cultural changes throughout the Gran Dolina TD10 Middle Pleistocene sequence (Atapuerca, Burgos, Spain)

Abstract

The Sierra de Atapuerca sites offer a series of chronological sequences whose correlation allows the paleoenvironmental and cultural evolution during the Early and Middle Pleistocene to be reconstructed. Previous work in these sites showed the difficulties in identifying clear cut-off points separating entirely different environmental episodes along the sequence, which lacks evidences of extremely harsh conditions. Another difficulty was relating the paleo-environmental changes with the cultural ones. Here we present a multiproxy analysis focused on the Middle Pleistocene unit TD10 of Gran Dolina site, which is the richest archaeological unit being excavated in Atapuerca. Our main goal is to describe in detail the 3m thick stratigraphic succession of TD10, and to situate the most significant geological, geochronological, paleoenvironmental, palaeontological and archaeological information recovered up to now in the most representative profiles. The main purposes of such a multidisciplinary presentation are to identify specific micro-scale environmental variations through the TD10 sedimentary unit, and to assess how they are reflected in the archaeo-palaeontological record. A total of twelve “sample units” (layers) have been individualised in the TD10 succession, from top to bottom: four in sub-unit TD10.1, four in TD10.2, two inTD10.3 and two in TD10.4. One extra control point was taken in level TD9, just to record the differences between these apparently so diverse units. Each of these points has been specifically sampled, and data coming from different fields of study is taken into account separately. Data sources broadly include geology (sedimentology, stratigraphic features, soil micromorphology observations and geochronology), environment (pollen, small and large fossil vertebrate remains) and archaeology (behavioural data coming from technological and zooarchaeological studies). A first step in the study involves combination of these proxy data to characterise each of the control points, which will lead us to define hypothetically synchronic and homogeneous associations. This will allow us to draw preliminary hypotheses, which intent to correlate environmental and cultural data for these homogeneous layers. A second step involves an analysis of the evolution of the archaeological and palaeontological assemblages from the sucession of TD10, taking into account the evolutionary trends of all those features considered significant, both for environmental and cultural aspects. The excavation and sampling strategy is demonstrated to be fruitful to characterise specific layers in the TD10 sequence. It allows a better description of both environmental and cultural aspects than previous studies, which were based on larger units of analysis. The comparison of the different synchronic associations, which have been observed, is useful from an evolutionary perspective. In its turn, the diachronic framework proved to be useful to properly contextualise some of the archaeological issues of TD10 already published. In general terms, we can conclude than environmental constraints hardly explain by themselves the identified cultural changes. However, the combined information for each selected layer furnished crucial data to contextualise and to improve the characterisation of the varied subsistence strategies of the hominins who left their archaeological evidence in TD10 during the late Acheulean.