- journal_title：Geological Society of America Bulletin
- Contributor：Rodolfo Coccioni ; Andrea Marsili ; Alessandro Montanari ; Adriana Bellanca ; Rodolfo Neri ; David M. Bice ; Henk Brinkhuis ; Nathan Church ; Alison Macalady ; Aaron McDaniel ; Alain Deino ; Fabrizio Lirer ; Mario Sprovieri ; Patrizia Maiorano ; Simonetta Monechi ; Claudio Nini ; Marisa Nocchi ; Jörg Pross ; Pierre Rochette ; Leonardo Sagnotti ; Fabio Tateo ; Yannick Touchard ; Stefaan Van Simaeys ; Graham L. Williams
- Publisher：Geological Society of America
- Date：2008-
- Format：text/html
- Language：en
- Identifier：10.1130/B25988.1
- journal_abbrev：Geological Society of America Bulletin
- issn：0016-7606
- volume：120
- issue：3-4
- firstpage：487
- section：STRATIGRAPHY
The Oligocene represents an important time period from a wide range of perspectives and includes significant climatic and eustatic variations. The pelagic succession of the Umbria-Marche Apennines (central Italy) includes a complete and continuous sequence of marly limestones and marls, with volcaniclastic layers that enable us to construct an integrated stratigraphic framework for this time period. We present here a synthesis of detailed biostratigraphic, magnetostratigraphic, and chemostratigraphic studies, along with geochronologic results from several biotite-rich volcaniclastic layers, which provide the means for an accurate and precise radiometric calibration of the Oligocene time scale. From this study, the interpolated ages for the Rupelian/Chattian stage boundary, located in the upper half of Chron 10n at meter level 188 in the Monte Cagnero section, and corresponding to the O4/O5 planktonic foraminiferal zonal boundary, are 28.36 Ma (paleomagnetic interpolation), 28.27 ± 0.1 Ma (direct radioisotopic dating), and 27.99 Ma (astrochronological interpolation). These ages appear to be slightly younger than those reported in recent chronostratigraphic time scale compilations. The Monte Cagnero section is a potential candidate for defining the Chattian Global Stratotype Section and Point (GSSP) and some reliable criteria are here proposed for marking the Rupelian/Chattian boundary according to International Union of Geological Sciences (IUGS) recommendations.