Oceanic affinities of the Alpha Ridge, Arctic Ocean

Abstract

Geological and geophysical information collected on the ice station CESAR have been integrated to develop an origin and history for the Alpha Ridge. The fossil assemblage recovered limits its age to no younger than Late Cretaceous. Fragmental alkaline volcanic rocks were dredged from the escarpments of the trough system. A high-velocity lower crust and depth of nearly 40 km to mantle is revealed by the refraction experiment. Cretaceous aseismic oceanic plateaus of the Pacific exhibit striking similarities to the Alpha Ridge. Plate reconstructions are presented that rotate the Arctic-Alaska plate away from the North American plate, with the Alpha-Mendeleev Ridge complex on a spreading centre being fed by a hot spot forming a feature similar to the Iceland-Faeroe Plateau. © 1986.