--> Abstract: Tectonosedimentary History of the Sedimentary Basins in Northern West Siberia, by N. Ya. Kunin and I. E. Segalovich; #90990 (1993).

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KUNIN, N. YA., and I. E. SEGALOVICH*, Institute of Physics of the Earth, Moscow, Russia

ABSTRACT: Tectonosedimentary History of the Sedimentary Basins in Northern West Siberia

Sedimentary basins of northern west Siberia belong to the Arctic tectonosedimentary province. This basin evolved dissimilarly compared to those in the Urengoy and more southern areas, which resulted in substantial differences in the geologic characteristics. Seismic surveys indicate that the basement surface in northern west Siberia occurs at great depths, in places exceeding 15 km. The depressions of the basement surfaces are filled with the thick Paleozoic and Mesozoic sequences.

The paper discusses the results of seismostratigraphic analysis of more than 13,000 km of regional common-depth-point profiles. These profiles identified systems of east-west-trending and isometric structures in the region. Some of the structures are buried; others are mapped in the upper horizons of the sedimentary cover and decrease in magnitude with depth.

The following results of the seismostratigraphic analysis are especially important for understanding the petroleum geology.

(1) Cretaceous marine sediments that were deposited under deep-water conditions and did not compensate for the tectonic subsidence are widely present in the region. Noncompensated sedimentation was the longest from the Late Jurassic to the Hauterivian-Barremian on the Gydan peninsula and in adjacent areas.

(2) The Jurassic section is dominated by ingressive marine sediments. Sediments that did not compensate for tectonic subsidence widely occurred in the Early Jurassic and resulted in deposition of petroleum source rocks.

(3) Triassic and Jurassic strata occur conformable in most of

northern west Siberia. Significant deformation of the Triassic sediments are identified in the periphery of the Triassic marine basin. This indicates that surrounding structures were thrust against northern west Siberia at the Triassic and Jurassic time boundary.

(4) Isometric structures of high magnitude were formed during the Paleozoic structure stage; this structure continued to grow through the Triassic and Jurassic.

These and other results of seismostratigraphic analysis suggest the high oil potential of the region.

AAPG Search and Discovery Article #90990©1993 AAPG International Conference and Exhibition, The Hague, Netherlands, October 17-20, 1993.