South Anyui Suture from the New Siberian Islands: Implications for Two-Pole Model of the Amerasia Basin Rotational Opening
Geological Institute of Russian Academy of Sciences, Moscow, Russia.
The widely accepted rotational model for the Amerasia basin opening is well confirmed by the data for Canada basin and Alaska North slope (Grantz et al., 1990). The corroboration of the model by geologic evidences on the opposite side of the pole of rotation is much worse. The model requires that the arcuate rotational transform fault or suture zone should path along the foot of Lomonosov Ridge and then cross the Arctic shelf to join the South Anyui suture. In its way this fault zone must go through the New Siberian islands or pass near them (e.g. Lowver et al., 2002). Field examination of this region has proved that no Mesozoic suture split across East Arctic shelf. Tracing the Early Cretaceous South Anyui suture northwest from Chukotka has revealed that it comes to the Big Lyakhov island and then does not go north in the expected direction. Instead it turns back, outlines the Chroma Loop and comes to connection with the Kolyma Loop suture. This connection has far-reaching implications for Mesozoic tectonics of North Pacific region and for the Amerasia Basin origin (Kuzmichev, 2009). In particular this means that no oceanic basin separated Siberia and North America in Mesozoic. The entire continental shelf of the Laptev and East-Siberian Seas existed in Triassic and Jurassic as solid terrane whose west end was attached to Siberian Platform and Taimyr foldbelt in the fasion simillar to that of (Miller et al, 2006). This terrane was split off the Lomonosov Ridge margin and rotated clockwise in the course of the Amerasia basin opening which has lead to two-pole rotation model. The model provides predictable framework for East-Siberian shelf bedrock geology. In particular, Permian, Triassic and Jurassic deposits that contain oil-source beds can be traced through the shelf of Laptev and East-Siberian Seas. These deposits may contribute to possible hydrocarbon storages in the Late Cretaceous-Tertiary reservoirs.
AAPG Search and Discover Article #90096©2009 AAPG 3-P Arctic Conference and Exhibition, Moscow, Russia