Geoarchaeology and paleontology of the Late Pleistocene deposits at the former Abroñigal Stream (Manzanares Basin, Madrid): the Puente de Los Tres Ojos Site

Abstract

The archaeological excavation of the Puente de los Tres Ojos site, next to Cerro Negro Street (Madrid), has provided new data that has allowed us to go in depth into the human settlement and the palaeoenvironmental reconstruction of the old Abroñigal stream valley, whose fluvial course worked as a tributary of the Manzanares River probably from before the Late Pleistocene up to the second half of the XXth century. In this paper we present the geomorphological and chronostratigraphic data of the excavated layers, documenting the various sequences of the fluvial and alluvial deposits that have filled the right bank of the Abroñigal valley bottom within its lower stretch. A large collection of lithic pieces has been obtained during the excavation works, most of which have been found within medium energy deposits of sands and gravels, being the rest associated to argillaceous slimes and thin sand deposits. The majority of the lithic collection responds to technical systems of the Middle Palaeolithic, although it is noteworthy the testimonial presence of pieces belonging to the Upper Palaeolithic, as well as mammal faunal remains from the Late Pleistocene. The dates obtained through OSL place the chronology of the deposit between approximately 14,400 and 11,170 years BP.