Palynological analyses of Eocene to Oligocene sediments from DSDP Site 338, Outer Vّring Plateau

Against the background of the profound global climatic shift from greenhouse to icehouse conditions during the Eocene–Oligocene transition, major geographic and oceanographic changes were taking place in the Norwegian–Greenland Sea region. The Vøring Plateau was a prominent structural feature which influenced the evolution of water mass circulation in the Nordic seas, and we present detailed palaeoenvironmental reconstructions of this structure. New palynological results suggest that shallow water inner-neritic environments were developed across parts of the Vøring Plateau during early Eocene times, with terrestrial and brackish water palynomorphs indicating that both basement highs to the north, and the crestal part of the Vøring Escarpment, may have been emergent. A transition from marginal-marine to open marine conditions occurred around 44 Ma ago, with the complete subsidence of the Vøring Plateau below sea level, facilitating inter-basinal surface water circulation and promoted a significant increase in photic zone fertility. Carbon sequestration associated with such enhanced productivity in the late Eocene Nordic seas may have contributed to declining Cenozoic atmospheric carbon dioxide levels, thence to declining global temperatures and the development of limited Northern Hemisphere continental ice on Greenland in the latest Eocene.