Marine-continental magnetobiostratigraphic correlation of the Dolomys subzone (middle of Late Ruscinian): implications for the Late Ruscinian age

摘要

Lacustrine deposits, which form part of a continental unit cropping out in many localities of the Jerez Basin (SW Spain), have for the first time been dated. These deposits are attributed to the lower part of the Dolomys subzone, the upper part of the MN 15 Neogene Mammal Unit (late Ruscinian). This continental unit unconformably overlies a marine unit. Since the isochrony of the unconformity is not precisely established, the biostratigraphic results and palaeomagnetic data give two possibilities in correlating the Dolomys subzone with the marine magnetobiostratigraphy: (1) it can be correlated with the C2Ar reversed-polarity chron, or (2) with the C2An.2r reversed-polarity subchron (or C2An.1r ?). Therefore, the lower boundary of the MN 15 would be at the base of the C2Ar or at the very top of the Early Pliocene, respectively. In any case, considering the magnetobiostratigraphy correlation carried out in other Pliocene continental basins of the southeastern Spain, the top of MN 15 seems to be within the Late Pliocene.