Late Miocene magnetostratigraphy, biostratigraphy and cyclostratigraphy in the Mediterranean

Abstract

A new chronology for the late Miocene of the Mediterranean is presented by combining magnetostratigraphic, biostratigraphic (planktonic foraminifera and dinoflagellates) and cycle-stratigraphic data. Long and continuous upper Miocene sections on Gavdos (Metochia section) and Sicily (Gibliscemi section) display cyclic alternations of homogeneous marls and sapropels and can be correlated on the basis of their distinct cyclic patterns. The Metochia section yields a good paleomagnetic signal and the position of 17 polarity reversals can be determined. The resulting polarity sequence allows an unambiguous correlation to the geomagnetic polarity time scale (GFTS). The paleomagnetic signal in the Gibliscemi section is too weak to determine a reliable polarity sequence, except for the lowermost part of the section. Detailed biostratigraphic analysis results in the identification of 13 planktonic foraminiferal and 9 dinoflagellate bioevents, which can all be accurately dated. The Tortonian/Messinian boundary, defined by the First Regular Occurrence (FRO) of the G. conomiozeu group, is determined in chron C3Br.k with an age of 7.12 Ma, according to the GPTS (CK95) of Cande and Kent [l].