ABSTRACT: Tectonic Framework of the Northeastern U.S.S.R., Implications for Oil and Gas Exploration

CECILE, M. P., J. C. HARRISON, and L. S. LANE, Geological Survey of Canada, Calgary, Canada, and M. K. KOS'KO, Sevmorgeologiya, St. Petersburg, Russia

The northeastern U.S.S.R., like Alaska, can be divided up into a northern Arctic plate and a collage of Pacific-side terranes that are

joined together along the ultramafic-bearing South Anyui Foldbelt. The northern Chukotkan Plate is considered continuous with the Arctic Alaska Plate and includes the continental shelves of the East Siberian and Chukchi seas, half of which are underlain by large, relatively undeformed Cretaceous-Tertiary sedimentary strata; and the northern Chuktoka Peninsula, which includes the Chukchi Massif. The southern terranes are cored by the Omolon and Kolyma massifs. All three massifs are circular with gneissic cores and mantles of Proterozoic metasedimentary strata. The southern two massifs are surrounded by Mesozoic fold belts with various trends that merge on the west with the Verkhoyansk Foldbelt, which is located on the eastern edge of the Siberian Platform. All plates and terranes of th Chukotkan Peninsula are overlapped by the Albian-Cenomanian Okhotsk-Chukotsk epicontinental volcanic belt. Most of the Chukotkan Plate like the southern terranes underwent intense Triassic-Early Cretaceous deformation and metamorphism, and rocks older than Lower Cretaceous are unlikely candidates for reservoirs or source rocks. In addition, in comparison to the Arctic Alaskan Plate the main front of Mesozoic deformation in the Chukotkan Plate is offset 600+ km northwest close to the edge of the continental shelf of the western Chukchi Sea.

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)