THE ROSSELLO COMPOSITE - A MEDITERRANEAN AND GLOBAL REFERENCE SECTION FOR THE EARLY TO EARLY LATE PLIOCENE

A high-resolution magnetostratigraphy (planktonic foraminiferal) biostratigraphy and cyclostratigraphy is presented for the Pliocene Trubi marls in the Punta di Maiata section on Sicily. The integrated stratigraphy of the Rossello composite section of Hilgen ([1], Newslett. Stratigr., 17, 1987) is thereby completed. This composite section provides an unprecedented high-quality reference section for the Early to early Late Pliocene, containing a continuous sequence ranging from below the Thvera Subchron into the Matuyama Chron (4.86-2.45 Ma). The Punta di Maiata section extends from the Sidufjall Subchron of the Gilbert into the Gauss Chron (4.50-3.30 Ma). Linear interpolation between paleomagnetic datum planes in this section yields first-order age estimates of 3.72 (+/- 0.01) and 3.59 (+/- 0.01) Ma for the last common occurrence (LCO) and the actual last occurrence (LO) of Globorotalia margaritae. In addition, this age of 3.59 Ma provides an accurate age for the Zanclean-Piacenzian (Z/P) boundary, provided the LO of G. margaritae is maintained as a criterion to define this boundary in the Mediterranean. Irrespective, however, of the criterion used, the Punta di Maiata and Punta Piccola subsections of the Rossello composite are at present the most suitable sections to be designated as stratotypes for the Z/P boundary. The global significance of the Rossello composite is further strongly enhanced by the establishment of an astronomically calibrated geomagnetic polarity time scale based on the correlation of the Trubi sedimentary cycles with the astronomical record.