Structural units of the central arctic and their relations to the mesozoic arctic plume

The integration of information obtained from onshore and offshore geological and geophysical research undertaken in the context of the International Polar Year has led to the following results. The continental crust is widespread in the Arctic not only beneath the shelves of polar seas in the framework of the Amerasia Basin but also in the Chukchi-Northwind, Lomonosov, and Mendeleev ridges; a combination of continental and oceanic crusts is inferred in the Alpha Ridge. The Amerasia Basin is not an indivisible element of the Arctic Ocean either in genetic or structural terms but consists of variously oriented basins different in age. The first, Mesozoic “minor ocean” of the Arctic Ocean—the Canada Basin—arose as a result of impact of the Arctic plume on the high-latitude region of Pangea. This inference is supported by the vast Central Arctic igneous province that comprises the Jurassic-Mid-Cretaceous within-plate and ocean-island basaltic and associated rocks. The rotational mechanism of opening of this basin is explained by the slant path of the plume head motion, which resulted in breaking-off and displacement of a fragment of Pangea. The effect of the Arctic plume was expressed during all stages of the opening of the Canada Basin and exerted effects on the adjacent part of the Eurasian continent during the formation of the Verkhoyansk-Chukotka tectonic domain. The Canada Basin was an element of the segmented system of Atlantic spreading ridges, while the Arctic plume that initiated its evolution was genetically related to the episodically acting African-Atlantic superplume. In comparison with the Pacific superplume, the low productivity of African-Atlantic lower mantle upwelling became the cause of slow and ultraslow spreading in the Atlantic and Arctic oceans and determined the passive character of their margins, including the Canada Basin.