Mesozoic History of the Arctic Islands

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Abstract
Mesozoic strata are widespread in the Canadian Arctic Islands and occur in diverse tectonic-stratigraphic settings (Fig. 14.1). The Sverdrup Basin, which was a major depocentre in the Arctic Islands from Carboniferous to early Tertiary, contains the thickest and most complete Mesozoic succession in the region. In the central portion of the basin Triassic to Cretaceous deposits are up to 9 km thick (Fig. 14.1 ; for well sites and geographic names see Fig. 1, in pocket). Mesozoic rocks in eastern Sverdrup Basin were folded and faulted by regional compression in early Tertiary, and excellent exposures occur in mountainous terrain. To the west, the structures and terrain have much lower relief and outcrop is mainly Cretaceous or younger in age. Banks Basin on Banks Island (Fig. 4.3) contains a gently-dipping, 1200 m succession of Upper Jurassic to uppermost Cretaceous strata. Scattered outliers of flatlying to tilted Cretaceous strata occur in the Franklinian mobile belt, Arctic Platform and Canadian Shield geological provinces. These outliers are areally restricted and thin, and commonly lie in grabens. Cretaceous strata are also interpreted to occur beneath thick Tertiary deposits along the continental shelf northwest of the Arctic Islands, in eastern Lancaster Sound, and on the continental shelf east of Baffin Island. The nature and thickness of these offshore and deeply buried strata are unknown owing to a lack of data. The Mesozoic succession in the Arctic Islands consists almost entirely of clastic sediments. In Sverdrup Basin, sandstone units occur mainly on the basin margins with shale-siltstone