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The AAPG/Datapages Combined Publications Database

CSPG Special Publications

Abstract


Canada's Continental Margins and Offshore Petroleum Exploration — Memoir 4, 1975
Pages 501-524
Arctic Ocean Margins

Geological History of the Arctic Ocean Basin

David L. Clark

Abstract

The central Arctic Ocean Basin is an irregular triangular shaped basin that averages about 3500 meters in depth. The deepest part approaches 5000 meters. The principal abyssal plains are interrupted by four prominent highs, the Nansen and Lomonosov Ridges, and the Alpha Cordillera and Chukchi Plateau. The ridges are important to interpretations of the basin’s origin.

Present seismic activity along the Nansen Ridge and its geographic continuity with the mid-Atlantic Ridge suggests that the former is the modern Arctic Ocean spreading axis. The Lomonosov Ridge probably represents a portion of the Barents Shelf that has been separated by movement away from the Nansen Ridge. Geology of the area surrounding the Arctic Basin has been used as evidence that the ocean existed during most of the Phanerozoic. An alternative idea is that the basin may be younger, and originated during the Mesozoic by drifting of the present Kolyma block from the central Arctic into the Siberian platform.

A mixture of glacial debris, clay and foraminifera comprise the Pliocene and Pleistocene sediment of the Chukchi Plateau and Alpha Cordillera. Turbidites are common in the deeper Canada Abyssal Plain. Cretaceous and lower Cenozoic tuffaceous sediment has been obtained from the Alpha Cordillera.

There are different theories concerning the origin of the Arctic Basin. There is general agreement that the Eurasian part has formed as a result of spreading away from the Nansen Ridge during the past 40 million or possibly 60 million years. There is no consensus concerning the Amerasian part. One theory proposes that the present Arctic Basin originated with spreading along the Alpha Cordillera in the late Mesozoic-early Cenozoic and attained its modern configuration with development of a second spreading axis along the Nansen Ridge in the middle Cenozoic.

More recently, the Alpha Cordillera has been interpreted to be a subduction zone related to expansion of the Atlantic Ocean Basin. The Mesozoic Arctic Basin was much warmer than it is at present. The Arctic Ocean obtained an ice-cover during the middle Cenozoic and has maintained it to the present.


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