Architecture of the Canadian portion of the High Arctic Large Igneous Province and implications for magmatic Ni–Cu potential

Abstract

The Cretaceous to Paleogene High Arctic Large Igneous Province (HALIP) occurs in circum-Arctic regions, and the largest portion of the province occurs in Canada’s Arctic Archipelago. This paper reviews and documents the geometry and distribution of the Canadian portion of the HALIP, focussing most notably on the architecture of its intrusive component. The extent of dyke swarms and sills of the Canadian HALIP is updated and is shown to be greater than previously acknowledged. Sills, in particular, occur throughout the Sverdrup Basin and crop out extensively on Axel Heiberg Island within Triassic to Cretaceous strata. The HALIP event is dominantly intrusive, with 3–5 times more intrusive rocks than extrusive rocks, by volume. There is local evidence of syn-emplacement fault activity, possibly involving the reactivation of older faults, controlling the emplacement of dykes. In the eastern Sverdrup Basin, exposures of components of the HALIP are controlled by tectonic elements of the Eocene Eurekan Orogeny, with plumbing systems (dykes, sills) exposed along regional-scale anticlines or the hanging walls of thrusts. Portions of the HALIP have been shown to be prospective for magmatic Ni – Cu – platinum group elements (PGEs) based on geochemistry, and although geochemical controls play a critical role in the genesis of such deposits, structural and magma dynamic controls are also important to consider at the scale of 1–10 km magmatic complexes. Underpinned by the architecture of the Canadian HALIP, we document the structural characteristics of three 1–10 km-scale volcanic–intrusive complexes of the province that show Ni–Cu–PGE prospectivity: the volcanic–intrusive complex of the Strand Fiord – Expedition Fiord area, the Surprise Fiord dykes, and the Wootton Intrusive Complex. All three represent physico-structural environments that would likely promote high magma flowthrough and sulphide transport, and could be targeted for Ni–Cu–PGE magmatic sulphide mineralization.