NATAPOV, L. P., Aerogeologiya, Moscow, Russia

ABSTRACT: Tectonic Evolution of Northwest Siberia

The ancient Siberian continent was split from early Pangen in early Riphean. The newly formed continent drifted from the southern to the northern hemisphere, reaching high altitudes only in the Late Paleozoic. Up to the Early Carboniferous, a typical passive margin of the Atlantic type, prograding to the ocean, developed along the present northern and eastern boundaries of this continent.

In Upper Paleozoic, Triassic, and Jurassic, the carbonate sedimentation was replaced by the accumulation of thick terrigenous complexes along the northern and southern margins. Large submarine plains were formed by the merging of fans, while eustatic lowering of the ocean level enlarged the source area of detrital material. Distal facies, with time, were moving into the ocean.

Rifting, penetrating inside the continent, conditioned the formation of large sedimentary basins. The development of the Sukhanskaya syneclise is associated with Riphean rifting, and Vilyuiskaya with Upper Devonian rifting.

In the Upper Mesozoic, the convergent boundaries of lithospheric plates existed along the northern and eastern boundaries of the Siberian continent. As a result of the final collision of the continental margin with blocks of different nature (microcontinents, island arcs, etc.) transported by the Kula plate, and with chukchi and north Taimyr arctic blocks, Verkhoyansk and Taimyr fold belts appeared in the Upper Cretaceous. They were overthrusted on clastic wedges, putting into shape the present-day structure of foredeeps.

In the paper, principal attention is devoted to peculiarities of structure and development of sedimentary basins, formation of oil-producing complexes, and structures favorable for accumulation of hydrocarbons. All these features are analyzed at the background of this plate tectonic scenario.

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