Abstract

A large number of dredge hauls made on the outer shelf and slope east of the Faeroe Islands have yielded Lower Tertiary sedimentary rocks (both in situ and glacially transported). The rocks have been examined petrographically and biostratigraphically (dinoflagellates), and they are all considered to be derived from the Faeroe shelf. They can be classified according to sediment type and chronostratigraphy in the following groups: (1) Lower Eocene basaltic tuffs (dominantly non-marine); (2) Lower and Middle Eocene tuffaceous limestones and phosphatic sediments; and (3) Lower and possibly Upper, Oligocene fine-grained feldspathic volcanic sandstones. Two dredge hauls of local till near the shelf edge west of the Faeroe Islands gave coarse to fine grained volcanic sandstones of Oligocene age.

The basaltic tuffs of the eastern shelf bear witness to a major phase of explosive volcanism succeeding the extrusion of the Faeroe lava plateau. Whole-rock chemical analyses suggest that the explosive magmas had a tholeiitic composition rich in iron and titanium. Some of these eruptions are likely to be represented among the tuffs of the Balder Formation in the North Sea. After the deposition of the tuffaceous sediments in a marine setting during the Early and Middle Eocene the central parts of the Faeroe basalt plateau were probably uplifted in the Bartonian or Priabonian. As a result of erosion of the basalt plateau and overlying sediments volcanic sandstones (often rich in reworked dinoflagellates) were deposited in a marine environment during the Early Oligocene.