Biochronology of the Complex Terrace of Butarque of the Manzanares river at the Stormwater Tank in Southern Madrid (Spain)

Abstract

Due to the construction of the Stormwater Tank in Villaverde (Madrid), two new Pleistocene vertebrate bearing sites were discovered within the sediments of the Complex Terrace of Butarque (TCB, in Spanish), called H-02 and H-03. Termoluminiscence (TL) dates placed the first site at the Late Pleistocene, more precisely at the end of the MIS 5. An older age within the Middle Pleistocene was obtained for H-03 (Domínguez-Alonso et al., 2009). In this work, we evaluate the agreement between the TL dates and the estimated ages resulting from the biochronological interpretation of the fossil mammal assemblages recovered in both sites. Whereas for H-03 there is consistency between the TL dating and the age estimated based on biocronological criteria, this is not the case for H-02. At this site, the presence of Microtus brecciensis points to an older age than the proposal based on TL, within the Middle Pleistocene. On the other hand, comparison of some biometric features between the H-02 and Áridos 1 populations of the last species allows to establish a younger age for the first site with regard to the second one. Taking into account the available dates for Áridos 1, which placed this site at the end of the MIS 11 (Panera et al., 2011), the age of H-02 must therefore be included in the last quarter of the Middle Pleistocene. In summary, TL dates for the H-02 site and, perhaps, some others obtained for the Stormwater Tank in Villaverde, seem to be minimum estimations of the age of the sediments, and do not represent their real age.