A synthesis of Norwegian Sea biostratigraphies: ODP Leg 104 on the Voring Plateau

Abstract

Summaries are presented of the 12 biostratigraphic contributions to this volume, which treat the calcareous, siliceous, and organic-walled microfossils preserved in the 1319.1 m of sediments and the thin shales intercalated in the 914.0 m thick basalt series recovered on Leg 104. Biostratigraphic range data are synthesized into a lower Eocene to Pleistocene biostratigraphic framework for the sedimentary successions of the eight holes drilled at Sites 642, 643 and 644 on the Voring Plateau. Microfossil distributions discussed in the synthesis include: actiniscidians, Bolboforma, calcareous nannofossils, diatoms, ebridians, benthic and planktonic foraminifers, ostracodes, palynomorphs, radiolarians, and silicoflagellates. Time intervals of 3.2 and 4.9 m.y. at Sites 642 and 643, respectively, are represented by a major late-middle to early-late Miocene hiatus. This and 10 other hiatuses of lesser magnitude divide the Neogene sedimentary succession of the outer Voring Plateau into 10 sequences that are classified in a synthemic system. Leg 104 hiatuses are correlative with hiatuses recognized in the Pacific, and some appear to have equivalents in other regions of the Norwegian Margin and on the Jan Mayen Ridge. A biostratigraphic review of 14 Leg 38 sites indicates that the poorly understood Paleogene sedimentary successions of the Norwegian Sea may be represented by four major unconformity-bounded sequences of regional scope. -from Author