Where in the Amerasia Basin should IODP Drill?
Christopher J. Cooper1, Balazs Badics1, Elisabeth Bjerkebæk1, Erik Lundin2, Anthony G. Doré3, Terje Flaten1, and Erik P. Johannessen1
1Statoil ASA, Stavanger, Norway.
2Statoil ASA, Trondheim, Norway.
3Statoil ASA, Houston, TX.
The formation and evolution of the frontier Amerasia Basin and its surrounding land masses, remains poorly understood. We suggest IODP drilling sites that could resolve some of these key questions: what was the pattern of continental breakup? When did the Amerasia Basin form? What is the nature of the sub-basins and structural highs of the Amerasia basin? How are sediments and in particular source rocks spatially distributed? Chosen targets are within the IODP penetration capability of ~ 1.5 km, but ice cover could present a challenge.
Sediment starved structural highs of the Amerasia Basin represent the most realistic drilling targets. Our primary target is the Northwind Basin, of the Chukchi Borderlands. Grantz et al., (2010) proposed that the Borderlands rotated counter-clockwise away from the Siberian margin, thereby opening the North Chukchi basin in their wake. Our goal is to determine the age of the Northwind Basin, which in turn tests whether the Borderlands have rotated. Previous interpretations date the Northwind Basin as Paleocene, post-dating both the formation of the Amerasia Basin and the proposed rotation. An alternative scenario is that the graben is a Mesozoic rift related feature, which prior to rotation of the Chukchi Borderlands paralleled the Siberian margin. The age of the Northwind Basin, whose size is greater than the North Sea, has significant implications for its hydrocarbon potential.
A second key target is the Alpha-Mendeleev ridge, whose nature remains unclear. One possibility is that the ridge was formed by a plume during the Cretaceous. Alternatively, the ridge could be of continental affinity. The nature of the ridge has significant implications for the continental breakup pattern of the landmasses surrounding the Amerasia Basin. The most widely accepted hypothesis is that Alaska and Arctic Siberia have rotated 66o with respect to Arctic Canada. This model requires the Lomonosov ridge, which separates the Amerasia and Eurasia Basins, to be a transform margin. This model would be invalidated if the Alpha-Mendeleev ridge contains continental crust. Furthermore, it would imply that continental crust underlies at least part of the most northerly portion of the Amerasia Basin, the Makarov and Podvodnikov basins.
Another of our targets is the De Long Plateau, of the East-Siberian continental margin, whose geology remains poorly understood. Finally, we would like to revisit the Lomonosov Ridge. IODP expedition 302 drilled this ridge, but the primary objectives were climatic and cores did not penetrate into crust.
AAPG Search and Discovery Article #90130©2011 3P Arctic, The Polar Petroleum Potential Conference & Exhibition, Halifax, Nova Scotia, Canada, 30 August-2 September, 2011.