Tectonics of the Arctic Ocean

摘要

The Arctic Ocean occupies a particular position on our planet. In contrast to the Southern Hemisphere of the Earth, where the Antarctic continent rises up to 3000 m above the sea level at its highest latitudes, the symmetrical North Pole area is occupied by an oceanic basin as deep as approximately 3000 m. The same contrast is notable for the tectonic evolution of the Earth. It is assumed that during the last 150 Ma the Antarctic continent was stable, remaining in practically the same geographic position, while the present-day structure of the Arctic Region was formed precisely during this time interval. The recent data on the bathymetry of the Arctic Ocean, its extended shelf included, allowed the specifying of the boundaries of the main bottom tectonic units (Fig. 1). In the central part of the ocean they include (from west to east): the Eurasia Basin with the median Gakkel Ridge, Lomonosov Ridge, Makarov Basin, Alpha-Mendeleev Ridge, and Canada Basin. Taking into consideration the age and structure of the basement, the Eurasian shelf of the Arctic Ocean can be subdivided (from west to east) into the Barents (Svalbard), Kara Sea, Laptev Sea, and East Siberian-Chukchi segments. The latter area includes the western part of the Beaufort Sea shelf. A narrow shelf extends from the Mackenzie River mouth along the Canadian Arctic Islands and northern Greenland. Only the eastern segment of the Eurasian Arctic, Canadian, and Alaskan shelves are coeval to the neighboring Canada deep-water basin. To the west, the shelf structures were formed long before the morphological elements that appeared in the central oceanic areas.