Radiometric dating and geochemistry of a tuff horizon from a mammal-bearing lacustrine sequence, Miocene Bicorp Basin, eastern Spain

The basin-fill sequence from the Bicorp Basin (Eastern Spain) comprises a lower alluvial unit and an upper lacustrine unit. The lower part of the lacustrine sequence includes a tuff bed, interbedded between two marnmal-bearing horizons which have yielded fossil rodents characteristic of the MN 10 standard mammal unit (Late Vallesian, Late Miocene). K-Ar age determinations on the tuff have provided a radiometric age averaging 9.6 ± 0.2 Ma (weighted average of two samples) for this ash fall deposito Major, trace and RE element analyses indicate that this tuff originated from a calc-alkaline evento The geochemical features of the Bicorp tuff, when compared with those from other calk-alkaline rocks from the Western Mediterranean, are not completely coincident. The stratigraphic correlation between the fossil mammal sites and the radiometrically-dated tuff allows a more precise calibration between the Late Miocene biochronological and geochronometric scale