The Cenozoic-Mesozoic Arctic Ocean and its Tectonic and Paleoceanographic Evolution: A Challenge for Future Scientific IODP-type Drilling
Wilfried Jokat and Ruediger Stein
Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany.
The geological history of the Mesozoic to Early Cenozoic Arctic Ocean remains one of the major gaps in our knowledge of the world ocean basins. This gap is primarily caused by the major technological/logistic problems in reaching this permanently ice-covered region. While the Cenozoic spreading at the Gakkel Ridge explains the opening of the eastern Arctic and the shapes of the continental margins between the Eurasian continental margin and Lomonosov Ridge, the nature of the Alpha-Mendeleev Ridge in the Amerasian Basin as well as the age of the deep sea basins are widely unknown. The current models suggest that the oldest Arctic deep-sea basin (Canada Basin) evolved in Jurassic times. Seafloor spreading opened the southern Canada Basin mainly in the Cretaceous. The Arctic Ocean for most of the Mesozoic consisted of an isolated deep-sea area with no major deep-water connection to the world ocean. Although this general model is widely accepted, details on the evolution of the Mesozoic Arctic are very limited especially for the ridges in the Amerasian Basin. For unravelling the Mesozoic to Cenozoic history of the High Arctic these ridges such as the Alpha-Mendeleev-Ridge and also the Lomonozoic Ridge, are the key areas for any drilling effort as they might contain a mainly undisturbed sequence of sediments. In addition, the tectonic history of the Fram Strait, the gateway between the Arctic and Atlantic oceans, are believed to have played an important role in regional to global paleoceanography and glaciations in the Northern High Latitudes. Compared with the importance of this gateway today for the climate of the Earth, only few details are known of its Cenozoic opening history and the impact on circulation and water mass exchange between the Arctic Ocean and the North Atlantic. Thus, a comprehensive scientific drilling programme composed of three major IODP-type drilling campaigns in the areas of Alpha-Mendeleev Ridge, Lomonosov Ridge and Fram Strait, has been proposed. This programme addresses a number of key questions raised in the IODP Initial Science Plan. Specific problems relating to Environmental Change, Processes and Effects, Solid Earth Cycles and Geodynamics and Extreme Climates, that can be divided into two major overall goals: understanding (1) the palaeoceanographic history and (2) the tectonic evolution of the central Arctic Ocean during the Mesozoic and the Early Cenozoic.
AAPG Search and Discovery Article #90130©2011 3P Arctic, The Polar Petroleum Potential Conference & Exhibition, Halifax, Nova Scotia, Canada, 30 August-2 September, 2011.����������������������������������������������������������������������������