Sverdrup Basin Composite Tectono-Sedimentary Element, Canadian Arctic Islands

Abstract The Sverdrup Basin Composite Tectono-Sedimentary Element (CTSE) covers 210 000 km 2 in the Canadian Arctic Archipelago. The CTSE was initiated in the Early Carboniferous by rifting of highly deformed Early Paleozoic strata and contains a maximum of 15 km of Carboniferous–Eocene strata. Eight phases of basin development have been recognized, with each being characterized by a specific combination of tectonic and depositional regimes. The phases are separated by intervals of uplift and tectonic reorganization, and each resultant first-order sequence is regarded as a separate TSE. Carbonate sedimentation was dominant in the Late Carboniferous and Early Permian, with clastic sedimentation becoming more common in the Middle Permian. Source areas lay to the east, south and north. In the Triassic, clastic sedimentation rates increased; and by the end of the Triassic, the central basin was filled. A shallow seaway was present throughout the Jurassic. In the Early Cretaceous, subsidence rates and clastic supply increased significantly, and basic volcanism occurred over most of the CTSE. Subsidence rate, sediment supply and volcanism decreased in the Late Cretaceous. The basin was progressively deformed in the Paleogene (Eurekan Orogeny), with local foreland deposits reaching 3 km. Seventeen oil and gas fields have been discovered on salt-cored, Eurekan anticlines. A combination of stratigraphic and structural traps, involving Triassic–Jurassic strata, has the greatest potential for future hydrocarbon discoveries.