Exploring the formation processes on open-air palaeolithic sites: A late Middle Pleistocene Acheulean assemblage at Arbo site (Miño River basin, Spain)

Abstract

The analysis of formation processes (e.g., degree of surface alterations, size ranges, orientation patterns, fabric features, density, spatial patterns, etc.) in archaeological sites provide relevant information about the type and intensity of sedimentary disturbances. This type of analysis is particularly important in Palaeolithic sites, especially when the stratigraphic context suggests certain sedimentary disturbances. This study follows a multivariate approach to the Acheulean site (pre-dating Marine Isotopic Stage -MIS- 5) at Arbo (Lower Miño basin, Spain). The two layers analyzed (levels OC1 and OC2) with archaeological remains (exclusively lithic artefacts) show matrix-supported gravel and cobble facies, which are compatible with extensive sedimentary disturbances. The results obtained demonstrate that sedimentary processes altered the archaeological assemblages in different ways, with some sorting and surface abrasion, in addition to a significant alteration of initial spatial patterns. However, the degree of disturbances observed is not sufficient to invalidate the documented techno-typological information, which is representative of the patterns of human behaviour at the site. This reinforces the importance of this type of analysis as a necessary step in the interpretation of any archaeological site, especially in Palaeolithic ages.