SHIPILOVE. V. Murmansk Marine Biological Institute, Kola Scientific Center, Russian Academy of Sciences, Russia

Based on a complex study and interpretation of marine geological and geophysical data, the main structural features of the Barents—Kara and other continental margins are considered in the context of reconstructions of the tectono-geodynamic environments that existed during breakdown of the last Pangea and resulted in the formation of young oceanic basins in the Arctic.

Attention is focused on three principal stages of the evolution of the region. 

In the Late Paleozoic—Early Mesozoic, the Arctic periphery of North Eurasia was affected by opposite tectono-geodynamic processes. The constructive (accretionary) regime was related to the collision or to its final phases responsible for the formation of North Eurasia, while the destructive regime was characterized by large-scale rifting induced by North Asian superplume activity. It cannot be ruled out that the Barents margin was influenced by one of the Paleo-Pacific offsets. The anomalous appearance of the East Barents basin with its avalanche-type, but starved accumulation of extremely thick sedimentary fill, the reduced Earth's crust and basaltic magmatism was a consequence of the interference of the above regimes.

In general, the stable regime of the evolution of the margin gave way to a mobile regime with an overall transition from carbonate to terrigenous sedimentation and with further stepwise intensification of destruction of the lithosphere eventually giving rise to the opening of oceanic basins in the Mesozoic and Cenozoic. The Jurassic—Cretaceous stage of oceanic basin formation determined the opening of the largest basin in the Arctic, the Amerasia Basin, is reflected in the tectono-geodynamic and facies rearrangements at the Barents Sea margin. The destructive, faulted propagation of the axial spreading zone from the Amerasia Basin to the continental margin was related to the system of SW—NE-trending deep riftogenic houghs directed toward the opening of the North Atlantic.

The Late Cretaceous— Cenozoic stage was characterized by the formation of the Norwegian—Greenland and Eurasia basins and development of the Arctic continental margins. The opening of young oceanic basins was accompanied by detachment of continental crystal blocks (microcontinents) from the margins, by shifts or jumps of oceanic spreading centers along the barrier-type transform zones at the continent—ocean boundary, by continental margin stretching (rifting) of the Earth's crust, by plateau-basalt magmatism, and by some other tectono-geodynamic phenomena relevant to the formation of the ocean.

ARCTIC SHELF OIL AND GAS CONFERENCE 2004