The nature of technological changes: The Middle Pleistocene stone tool assemblages from Galería and Gran Dolina-subunit TD10.1 (Atapuerca, Spain)

This article focuses on the origins for technological variation during the Middle Pleistocene through the analysis of the lithic assemblages from Galería and Gran Dolina-subunit TD10.1 (Atapuerca, Spain). The technological study was organized into three main levels of analysis. The first stage consisted of the technological characterization of the whole assemblage (e.g. the general composition of each sample, the exploitation and shaping methods used, and the characteristics of each item). The second stage involved the morphometric analysis of the large tools, mainly handaxes and cleavers, given the significance of these instruments in Middle Pleistocene assemblages. In this case, we combined traditional technical and metrical analyses with current morphometric methods. Lastly, taking into account the general characteristics of these sites, the third stage consisted of assessing how the different occupational strategies affected the lithic representation. These analyses allowed us to define three technological groups. The first includes unit Galería-GIIa, which corresponds to the appearance of the Acheulean in the Atapuerca caves. The second is represented by the rest of the sequence of the Galería site, mainly the upper part of the sequence (unit GIII). And the third technological corresponds to Gran Dolina-subunit TD10.1. Thus, the Galería sequence shows the technological evolution of the Acheulean over a period of 250 ka. Furthermore, subunit TD10.1 represents a new occupational strategy combining traditional Acheulean tools with more evolved technical strategies.