On the Issue of Barents-Kara Region Basement Age

Lidia Daragan-Suschova

A conclusion of basement age of Barents-Kara region different structures is drawn on the ground of modern seismic CDP profiles. The basement is Hercynian for the most part of South Kara syneclise as offshore water continuation of the West Siberia plate. Hercynian and more old folded complexes of the northern part of West Siberia plate have no Kara shelf continuation. They are limited by area of Early Cimmerian folds of Yamal-Pai-Hoy saddle connected even-aged folded belts of Novaya Zemlya and South Taimyr. Basement of the north part of Kara shelf is pre Upper Riphean that is clearly fixed on 4-AP profile. Upper Riphean-Cambrian strata unconformably bedding above it. On the Severnaya Zemlya archipelago these strata are terrigeneous flyshoid and molassoid formations. In the modern structure of Severnaya Zemlya these basal series are presented only in the troughs, where their thickness increased up to 7 km. At adjacent rises they are absent virtually. Ancient basement from the east is limited with Hercynian folding across the zone of fractures, and from the west – with Vendian one. According to CDP data, supplemented with borehole data and determination of magmatic and metamorphic rocks geochronology age, the basement of Pechora plate is Baikalian. The basement of Barents Sea shelf is uneven-aged. Under South Barents basin abutted against Pechora plate (profiles AP-3, KS-104) the basement is Baikalian. Under North Barents basin one can set another explanation of enclave nature with <> basement in the middle of more old surroundings. The basement under basin is neogenic, it came into existence as a consequence of vertical accretion, notably increasing of consolidated crust for account of lower parts of sedimentary cover. Critical review of chronostratigraphic potentiality of different geophysical methods is also done. The large number of interpretation versions of basement age to a considerable extent occasioned by the lack of complexification of different methods. Key words: Barents-Kara region, basement, age.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013