There is growing consensus that development of a semipermanent ice sheet on Antarctica began at or near the Eocene-Oligocene (E-O) boundary. Beyond ice-rafted debris in oceanic settings, however, direct evidence for a substantial ice sheet at this time has been limited and thus far restricted to East Antarctica. It is unclear where glacier ice first accumulated and how extensive it was on the Antarctic continent in the earliest Oligocene. Sediments at the top of the Eocene marine shelf section on Seymour Island, Antarctic Peninsula, include glacial marine deposits and a lodgment till with clasts derived from a variety of rock units on the peninsula. Dinoflagellate biostratigraphy and strontium isotope stratigraphy indicate an age at or very close to the E-O boundary. Glacier ice extending to sea level in the northern peninsula at this time suggests the presence of a regionally extensive West Antarctica ice sheet, and thus an even more dramatic response to the forcing factors that facilitated high-latitude ice expansion in the earliest Oligocene.

The Oligocene represents an important time period from a wide range of perspectives and includes signifi cant 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 defi ning 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.

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The Late Cretaceous and Cenozoic sedimentary record in the Campine Basin along the southern border of the North Sea Basin is analysed in terms of sequence stratigraphy. All available biostratigraphic, and in some cases, magnetostratigraphic data are used to constrain the sequence chronostratigraphy. The relative geographic extent of the strata is used as an indication of the relative sea level. Tectonic and eustatic components could be distinguished in several cases using regional geological information. Generally, sequences consist of transgressive and highstand systems tracts only and have flat, abrasiontype lower boundaries. Lowstand deposits are only identified as infill of erosional space, which generally implies marked tectonic uplift. Several eustatic and tectonic events can be correlated with similar events known elsewhere in the North Sea Basin. The time intervals spanned by the different sequences vary considerably, pointing out different control mechanisms.

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