Calibration of the Early-Middle Pleistocene transition in the continental beds of the Guadix–Baza Basin (SE Spain)

Abstract

The magnetostratigraphic and palaeontologic studies carried out in two sections in the Guadix–Baza Basin (SE Spain) have enabled an accurate calibration of the Early-Middle Pleistocene boundary in the continental beds of this basin. The palaeontological record (rodents) in the Cortes de Baza section indicates an age ranging from the earliest Pleistocene (latest Villanyian or early Biharian) to the late Early Pleistocene (late Biharian). The whole Cortes de Baza Section is placed in a reversed magnetic interval identified as the upper part of the Matuyama Chron. In the Guadix–Baza Basin, the Middle Pleistocene (early Toringian) was already known at the locality of Cúllar–Baza I, but new studies in the area have resulted in the recognition of Early Pleistocene deposits in the lower part of the section. Thus, the locality of Cúllar–Baza B is placed in a reversed magnetozone correlated with the uppermost Matuyama, while the locality of Cúllar–Baza C is placed in a normal magnetozone correlated to the lower Bruhnes Epoch. Therefore, the Biharian–Toringian boundary (based on the presence of Arvicola cantiana) falls well within the Bruhnes epoch. This result is consistent with what is found in other Early–Middle Pleistocene sections of Spain (Atapuerca Gran Dolina).