| Summary: | The presence of abundant age-diagnostic dinocysts at Site 913B (ODP Leg 151), Site 338 (DSDP Leg 38) and Site 643A (ODP Leg 104) has enabled the development of a high-resolution biostratigraphy for the Eocene-Oligocene interval in the Norwegian-Greenland Sea. This a particularly important as the calcareous microfossils usually used for biostratigraphy in this interval are generally absent in these high latitude Eocene-Oligocene sediments due to dissolution. In parallel with this biostratigraphic analysis, a new magnetic reversal stratigraphy has been defined for the Norwegian-Greenland Sea. This has allowed independent age determination and enabled the dinocyst biostratigraphy to be firmly tied into the global geomagnetic timescale for this period. Hole 913B, has proven to be the most complete and best-preserved record of the Eocene to Oligocene interval in the high latitudes of the Northern Hemisphere, thus have the potential to provide detailed palaeoenvironmental reconstructions of this critical period in early history. Integrated micropalaeontological, geochemical and environmental magnetic analyses of sediments from Site 913B have indicated that throughout the Eocene this site was located in a relatively offshore depositional environmental. Dinocyst and palynofacies assemblages from Site 338 indicate a transition from a marginal marine to a relatively deep-water offshore environment during the mid Eocene, reflecting the gradual subsidence of the Outer Voring Plateau and Voring Plateau escarpment. The final subsidence of these features occurs at ~46 Ma and is reflected by the cessation of predominantly terrestrially derived clastic sedimentation at Site 338. Coeval dinocyst assemblages indicate that a surface-water marine connection existed between the Norwegian-Greenland Sea and the North Sea, the Arctic Ocean and to a lesser extent the North Atlantic Ocean throughout the Eocene to Oligocene period. The Norwegian-Greenland Sea was characterised by relatively warm conditions in the early Eocene, which were ...
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