Tectonics of the Northeastern Siberian Arctic Continental Margin (Laptev, East Siberian and Chukchi Seas)

By

S. Drachev (Institute of Lithosphere, Russian Academy of Science) and L.A. Savostin (Laboratory of Regional Geodynamics— LARGE)

Numerous CDP seismic profiles were acquired in the past 15 years over the Northeastern Siberian Arctic Continental Margin (NSACM). Interpretation of these CDP data together with gravity data and onshore geological results helps to decipher tectonic structure and geological history of this region.

Geological data show that the basement of the NSACM formed during Middle Jurassic-Early Cretaceous collisions of the paleo- Siberian Continent with the Kara, Omolon and North Alaskan- Chukotkan microcontinents. A deformed paleo-Siberian continental margin underlies the western Laptev Shelf while the rest of the basement is composed of the North Alaskan-Chukotkan Microcontinent. The latter was initially attached to the North American Craton along the Inuit Fold Belt and then was broken apart during the Cretaceous opening of the Canada Basin, rotating counterclockwise and colliding with the paleo-Siberian and Omolon margins along the South Anyui Suture. In the course of this event the southern edge of the microcontinent was deformed (Brookian-Chukotkan Orogenesis), but its inner parts, as the Arctic and Chukchi platforms, De Long Massive, Arlis Plateau and Chukchi Borderland, remained stable constituting the Hyperborean Massive.

In the Late Cretaceous-Cenozoic NSACM was intensely rifted due to opening of the Arctic oceanic basins. The rifts extend landward from the shelf edge along the principal weakened zones in the basement. These are the abandoned New Siberian and Vil-kitskii rifts in the East Siberian Sea related to an inferred opening of the Makarov Basin between 33 and 80 Ma, and active Laptev Rift System, connected to the Cenozoic opening of the Eurasia Basin.

AAPG Search and Discovery Article #90008©2002 AAPG Pacific Section/SPE Western Region Joint Conference of Geoscientists and Petroleum Engineers, Anchorage, Alaska, May 18–23, 2002.