Geology and Evolution of the Northern Kara Sea Shelf

VINOGRADOV, ANDREY, Laboratory of Regional Geodynamics, LARGE International, Moscow, USSR

The interpretation of regional multichannel seismic reflection profiles collected during 1988-1987 yields the following features of the geology of the Northern Kara Sea Shelf (NKSS).

Two regional deep sedimentary basins are clearly distinguished within the NKSS. They have rather complex inner structures and contain sediments 14.0-16.0 km thick. The basins are separated from each other by a relatively narrow, linear zone of basement high which extends from Uedineniya Island on the south to Vize Island on the north, where basement depth is 1.5-4.0 km.

The sedimentary sections of the basins are composed of four lithological-stratigrahical sequences separated by unconformities which correlate well with the regional unconformities in adjacent land areas.

The initial stages of sedimentary basin development within the NKSS date back to the late Riphean-Vendian; probably they were associated with intracontinental rifting, when up to 4 km of sediments were deposited. During the most of the Phanerozoic, regional subsidence dominated; however, the rates of subsidence were different in the western and in the eastern basins, and varied in time for each basin. The subsidence was interrupted for relatively short periods when the region was affected by uplifts and erosion which resulted in formation of regional unconformities.

The seismic data gave no evidence of Caldeonian or any other Phanerozoic folding within the NKSS, which is in contrast with widespread assumptions.

The results show that the geological structure and evolution of the NKSS differ greatly from those of adjacent Barents and Southern Kara Sea shelves.

AAPG Search and Discovery Article #91007© 1991 AAPG International Conference, London, England, September 29-October 2, 1991 (2009)