Biostratigraphic evidence for evolving palaeoenvironments in the Lower Paleogene of the Faeroe-Shetland Basin

The results of biostratigraphic analysis of the Palaeocene to Lower Eocene section in four Faeroe-Shetland Basin wells are presented. The succession of bioevents is shown to be the same as that documented for wells in the North Sea. Evolution of microfossil assemblages within the basin reflects the change from an open marine setting in the Danian to more restricted marine and non-marine conditions in the late Thanetian and early Ypresian. This change is accompanied by a number of microfossil extinctions that form useful regional biomarkers for the Faeroe-Shetland and North Sea basins. These events include the extinction of planktonic foraminifera close to the Danian/Selandian boundary and the extinction of dinocyst taxa Palaeoperidinium pyrophorum and Areoligera cf. coronata at the Selandian/Thanetian boundary. Within the Thanetian section the extinction of Areoligera coincides with an abrupt reduction in numbers and diversity of agglutinated foraminifera. The Thanetian/Ypresian boundary is marked by the extinction of Apectodinium augustum. Well 208/19-1 lies in the marine, northeastern part of the basin, which was connected to the North Sea by a narrow seaway. However, upper Thanetian to lower Ypresian biofacies become increasingly restricted when traced southwestwards along the basin axis, with this interval being non-marine in 204/24-1A. (C) 2001 Elsevier Science Ltd, All rights reserved.