Geoarqueological data from the Manzanares River Complex fluvial terrace between the sectors of 12 de Octubre and the Butarque creek outler (Villaverde, Madrid)

Abstract

The archaeological excavations carried out during the years 2005 and 2006 in the 12 de Octubre Hospital and the Butarque creek outlet (South of Madrid City), offer new geological, archaeological and faunal data in order to characterize the evolution and dynamics of the Manzanares river valley during the Middle to Late Pleistocene transit. Both archaeological sites are located in the so called Complex Terrace of the Manzanares River (TCMZ), a complex and anomalously thickened fluvial terrace located at +22-16 m over the river thalweg. This fluvial level has been traditionally considered as Middle Pleistocene on the basis to the acheulean industry and faunal assemblages typically associated to their basal deposits. However this work indicates that the upper fluvial sequences of the TCMZ hold Mousterian industry belonging to the Late Pleistocene. The obtained data also indicate that the typically considered Late Pleistocene terrace levels (Mx) located at +12-15m and +11-9m along the river valley may display complex relationships of offlapping and overlapping with the TCMZ surface triggered by the occurrence of enhanced karstic subsidense, tectonics and relevant headward erosion steps in the riverbed. OSL dates (12 de Octubre) reported in this work can be interpreted as belonging to younger Mx deposits offlaped to the TCMZ with ages ranging between ca 33 and 40 ka BP. Data from the Butarque outlet refers to the basal fluvial levels of the TCMZ displaying a more ancient acheulean industry associated to fossil macrofauna assemblages typical of the Middle-Late Pleistocene in the Madrid Area. Finally, comparing the geomorphological, paleolithic and chronological (OSL) records of the Manzanares valley with other ones within the Tajo drainage basin, the TCMZ will develop, at least, until the end of the Last Interglacial (OIS 5) about ca 85-100 ka BP.