NEW MAGNETOSTRATIGRAPHIC AND AR-40 AR-39 DATING RESULTS FROM THE SUVA-MARL, FIJI - CALIBRATION OF THE EARLY PLIOCENE GEOMAGNETIC POLARITY TIME-SCALE/

The Suva Marl (Fiji) provides a rare opportunity to integrate Early Pl iocene biostratigraphic, magnetostratigraphic and chronostratigraphic data. We present new paleomagnetic data that extend the previously rep orted magnetostratigraphy [P. Rodda, I. McDougall, R.A. Cassie, D.A. F alvey, R. Todd, J.A. Wilcoxon, Isotopic ages, magnetostratigraphy, and biostratigraphy from the Early Pliocene Suva Marl, Fiji, Geol. Sec. A m. Bull. 96 (1985) 529-538] of the Suva Marl down section, and suggest a revision of the original correlation with the geomagnetic polarity time scale (GPTS). Ar-40/Ar-39 laser incremental-heating analyses of m ineral separates from the interbedded tuffs yield refined age constrai nts for previously reported K-Ar dates for the Suva Marl polarity reve rsals. The new dates and the new magnetostratigraphic data are most co nsistently interpreted as supporting the revised Early Pliocene polari ty time scale [W.A. Berggren, D.V. Kent, C.C. Swisher III, M.P. Aubry, A revised Cenozoic geochronology and chronostratigraphy, in: W.A. Beg gren, D.V. Kent, M.P. Aubry, J. Hardenbol (Eds.), Geochronology, Time Scales and Global Stratigraphic Correlation, Sec. Econ. Paleontol. Min eral. Spec. Publ. 54 (1996) 129-212]. The ages of the Suva Marl revers als derived from the Ar-40/Ar-39 dates provide a revised direct calibr ation of the early Pliocene GPTS, bringing it in synch with those cali brations produced by orbital tuning of Milankovitch cycles (astronomic al time scale). (C) 1997 Elsevier Science B.V.