Structure and potential oil and gas reserves of the pre-Jurassic (transitional) complex of the southeastern part of West Siberia

There are several different theories for the mechanism of development of pr e-Jurassic sequences in Western Siberia. Many geologists believe that Hercy nian-Caledonian and Bayikalian orogenies of the Paleozoic age affected all pre-Jurassic deposits. Others assume that pre-Jurassic-Paleozoic sediments were formed in the Paleo-Asian ocean that existed in Western Siberia. The m odel proposed by the writers is based on the analysis of the latest seismic data combined with the interpretation of geologic and other geophysical da ta, thereby allowing a reevaluation of both the new model and its more wide ly accepted predecessor. A new model concerning the geologic structure of p re-Jurassic deposits in the southeastern part of Western Siberia is propose d by the writers. It is based on the crucial identification of pre-Jurassic -Triassic Paleozoic sediments in the pre-Jurassic rift zones. Validation of such a model would prove to be crucial in that oil and gas plays of the so utheastern part of Western Siberia are known to be associated with the pre- Jurassic synrift sequences.