Abstract

Cretaceous volcanic rocks, which consist mainly of basalt flows and pyroclastic rocks, occur on northern Ellesmere Island, Axel Heiberg Island, and northernmost Amund Ringnes Island as part of the Sverdrup Basin succession. Volcanic rocks are associated with each of four regional transgressive–regressive (T–R) cycles that constitute the Cretaceous clastic succession of Sverdrup Basin and are of Valanginian – early Barremian, late Barremian – Aptian, latest Aptian – early Cenomanian, and late Cenomanian – Maastrichtian age; the volcanic component of each increases northward. The centre of volcanism appears to have been north of Ellesmere Island and is interpreted as the site of a mantle plume that was active throughout the Cretaceous.Most of the volcanic activity took place from Hauterivian to early Cenomanian (T–R cycles 1–3) and was accompanied by widespread sill and dyke intrusion. This activity coincided with the main rifting phase of the adjacent oceanic Canada Basin and with minor crustal extension in the Sverdrup Basin. From late Cenomanian to Campanian, volcanism was restricted to the extreme northeast, and trachytes and rhyolites were extruded along with basalts. This volcanic succession is interpreted as being the southern limit of Alpha Ridge, a major volcanic edifice that formed as a hot-spot track across Canada Basin during sea-floor spreading in Late Cretaceous.

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