Uralian Suture Under the Kara Sea?

Irene Gómez-Pérez¹, James Howard², and Robert Scott^3
1Repsol Exploration, Madrid, Spain
²CASP, Cambridge, United Kingdom
³CASP, Cambridge University, Cambridge, England

The Ural Mountains are the westernmost expression of a Late Paleozoic orogenic belt separating the Siberian and Baltica cratons. Late Paleozoic deformation also affected the sedimentary succession of Taimyr (northwestern Siberia). The Novaya Zemlya Foldbelt (Russian Arctic) is often considered the continuation of the Urals and Taymir, although its deformation is Late Triassic.
Facies distribution maps helped understand the tectonic evolution of this Arctic region in the Late Paleozoic-Early Mesozoic. As a result, we propose a Late Paleozoic suture under the Kara Sea linking the Urals and Taimyr foldbelts. The lack of present-day topographic expression is probably due to Late Paleozoic erosion and important Mesozoic subsidence. This new interpretation is supported by:
• Late Carboniferous clastic turbidites and a thick Permian submarine foreland basin succession with an eastern provenance in Novaya Zemlya, pointing to a landmass in the east
• Carboniferous-Permian deepening in Novaya Zemlya-Barents Shelf younging westward, probably reflecting orogenic loading from the east
• Lack of a suture zone or ophiolites in Novaya Zemlya; lack of geophysical expression of collisional orogeny or a plate boundary
• Undeformed Paleozoic rifts under the Triassic succession offshore eastern Novaya Zemlya, interpreted from geophysical data
• Minor strike-slip displacement between Pai Khoi and Novaya Zemlya, indicating arch geometry as an original feature of the Baltica margin
• Change in orientation of structures from NW-SE (Yamal Peninsula) to NE-SW (Kara Sea)
This has implications for hydrocarbon prospectivity, as undeformed Paleozoic passive margin successions, including Domanik source rocks and Devonian-Carboniferous carbonate reservoirs, could extend under the Kara Sea. It also has implications for the Barents basins, which acted as a foreland to different foldbelts (Caledonian, Uralian, Cimmerian), accumulating an enormous sedimentary thickness.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece