Tectonic Evolution of Barents Kara Region

Iliy Vinokurov¹, Alexandr Kalenich¹, Yuri Roslov¹, and Alexey Egorov^2
1Sevmorgeo, St.Petersburg, Russia.
²State Mining Institute, St.Petersburg, Russia.

The Western arctic margin of Eurasia is nowadays considered to be of ordinary passive type. Nevertheless there are some quite peculiar features characteristic of geological structure of the Barents-Kara region. Most important ones are huge shelf area, occurrence of overdeepened depressions and folding dislocation systems.

Modern tectonic pattern of pre-Cambrian crystalline basement of the Barents-Kara region is determined by interrelation of four big blocks: Svalbard (Barents) shelf plate, Timan-Pechora area and Kara shelf plate. In the southern part of the Kara paleobasin Paleozoic sedimentary cover is underlain by basic layer interpreted as a relic of ancient residual oceanic basin.

Thus mosaic block structure of pre-Cambrian basement made of crystalline blocks of various ages including those with residual oceanic crust is characteristic of the Barents-Kara region. These blocks were at the time the parts of huge Archean-Proterozoic cratons. Kara plate belonged to Siberian craton, Svalbard (Barents) plate - to North-American craton (Laurentia).

Analysis of features of most ancient Late Proterozoic - Early Paleozoic part of the sedimentary section of the Barents-Kara region shows that sedimentary cover was formed in the same structure-formation environment, so ancient rotational stresses resulted only in slight mutual removal of the mentioned cratons. Non-collision type of contacts predominates, though there are some relics of island arc systems.

Phanerozoic stage of development was characterized by domination of stress-strain environments resulted in destruction of crust layer with incorporation of more deep material. Areas of crust destruction predetermined subsequent location and evolution of big troughs including riftogeneous ones, where multi-age oil and gas source strata, collectors and cap rocks of various types were then deposited. Zones of the basement blocks jointing are prospective in terms of mineral generation and should be thoroughly studied.

Regional and global palinspastic reconstructions were made in order to clarify the trends of development of various folding belts and forming of sedimentary paleobasins within the Barents-Kara region. The results of investigations are supposed to be used as a starting point in analyzing mechanism of sedimentation on the Barents-Kara shelf. The analysis should be targeted at correlation of geodynamic processes of different types which in the course of pre-Mesozoic evolution went in the region and adjoining structures of West-Siberian, Enissey-Khatanga and Timan-Pechora sedimentary basins. It is our opinion that this will allow to indicate a number of new regional factors of localization of hydrocarbon fields and to make up-to-date multi-factors forecast.

AAPG Search and Discover Article #90096©2009 AAPG 3-P Arctic Conference and Exhibition, Moscow, Russia