A Revision of the Plate Rotation Models for the Opening of the Amerasian Basin Based on New Seismic Surveys in the Laptev, East Siberian and Chukchi Seas

Abstract

Of the numerous models explaining the opening of the Amerasian Basin, those showing northern Alaska and the East Russian Arctic Shelf rotating away from the Canadian Arctic around an Euler pole near the MacKenzie Delta have gained the widest acceptance. However, the rotational models leave a number of unresolved issues including: 1) were the New Siberian Islands originally part of a plate encompassing Alaska-Chukotka or were these two areas juxtaposed during the opening of the Amerasian Basin across a transform requiring hundreds to thousands of kilometers of right-lateral slip, and 2) how does the Chukchi Borderland fit into a reconstruction of the plates surrounding the Amerasian Basin? The new Eastern Russian ArcticSPANTM (ERAS), a survey consisting of >13000 km of seismic covering the Laptev, East Siberian and Chukchi seas, provides a wealth of new information addressing these issues. In our opinion, the data do not show a transform that would have separated the New Siberian Islands from the Chukotka-Alaska plate, but indicate continuity of geologic trends such as the Mesozoic thrust front from Wrangel Island west to the New Siberian Islands. The survey also shows the North Chukchi-Vilkitski Basin to be filled by some 20 km of Mesozoic and Tertiary sediments and floored by oceanic crust or exhumed mantle. The west side of the basin connects with the East Siberian Sea Rift, a feature that shallows and narrows to the south. Closing this rift around an Euler pole located at the South Anyui Suture both significantly shortens the east-west extent of the greater Alaska-Chukotka-New Siberia plate and allows the Chukchi Borderland to restore into the eastern end of the North Chukchi-Vilkitski Basin. When these observations are combined with (1) a moderately tight fit for Europe and the Lomonosov Ridge relative to North America, (2) restoration of the Eurekan orogeny of the western Canadian Arctic, and (3) a postulated orocline located just west of Prudhoe Bay on Alaska's North Slope, the circum-Arctic plates fit together with very few gaps. This plate reconstruction also brings paleomagnetic poles available for the Alaska-Chukotka-New Siberia plate into better alignment with the North American apparent polar wandering path, and presents several possible kinematic models that have implications for tectonic elements flooring the Amerasian Basin.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015