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Paleogeography of the Arctic – Implications for Mesozoic Sediment Routing and Basin Fill

Abstract

Prediction of lateral extent, thickness and quality of potential reservoir units in the subsurface requires basic understanding of regional basin evolution and depositional history. In remote areas where little data is available or where the basins have undergone major episodes of tectonic deformation, this understanding relies on integrated analysis of the plate tectonic framework and the resulting paleogeography. The Arctic has experienced several episodes of tectonic deformation which fundamentally changed basin configuration, distribution of topography and patterns of sediment routing on the regional scale. Here we present a set of new Mesozoic paleogeographic maps which highlight these fundamental changes. In the Triassic, the Arctic was characterized by a central restricted basin, which received clastic input from a number of source areas, the most prominent being the northern Scandinavia and the Urals. In the east, the Alaskan and Siberian passive margins received large volumes of clastics from continent-scale drainage systems tapping into the North American Craton and the Central Asian Foldbelt, respectively. In the Jurassic, the region was dominated be rifting as northern Canada rifted away from the main North American landmass. This fundamentally changed the paleogeography along the Alaskan margin as new source areas emerged as rift blocks and island arcs. In the Early Cretaceous, the rifting translated into a major shear zone (the Khatanga-Bering Transform) that extended from the Laptev Sea to the Bering Strait. As a result, the northern margin of the Barents Sea underwent regional uplift forming new source areas for clastic sediments that were shed southwards toward Scandinavia. Compared to the Triassic, this represents a fundamental shift in provenance. Similarly, mountain building in the eastern Siberia formed a continuous topographic high, which stretched from eastern Siberia to the east coast of North America. The resulting sediment load from this mountain belt caused major progradation into the newly formed Canada Basin. This overview of the Arctic plate tectonic history and paleogeography demonstrates the complexity of this overall data-poor area, and shows the need for an integrated, super-regional model in order to understand sediment routing and stratigraphic development in such areas.