The Lower Paleozoic complex of the West Kola Shelf as well as the underlying Riphean are similar not to the Scandinavian Caledonides but are more like the sections of Spitzbergen and the Pechora sineklize. The Lower Paleozoic section of the Central Barents high corresponds in thickness and facies with Cambro-Ordovician clastics and Ordovician carbonates of Spitzbergen. In the Pechora sineklize it is an analog of the Izma-Omra Complex. In spite of this correlation being based on seismic material, which gives only a general representation of compo- sition of the rocks, it nevertheless shows graphically that the similarity is significantly greater than with the Scandinavian sections. In contrast to the latter they exhibit neither facies characteristics of extra-shelf (oceanic or geosynclinal) sedimentation nor structural characteristics of Caledonian collision.
In order to elucidate the structural and compositional nature of the Lower Paleozoics of Spitzbergen, Central Barents high, and Pechora sineklize, which show no connection in the modern structural plan, it must be taken into account that these terranes were located in different positions at the end of the Early Paleozoic, that is, before the Permo- Triassic rifting. These later tectonic features must be "combed out" of the modern structural plan.
Palinspastic reconstruction of the Barents Sea region, taking into account Middle and Late Paleozoic rifting, shows that the structures of Spitzbergen, Central Barents high, and Pechora sineklize before breakup were a single elongate, relatively narrow belt of east-west oriented epi- platformal downwarps, which served as a connection between the Scandinavian and Ural Ocean basins. It is proposed that the part of this belt that extends into the Central Barents high be called the buried West Kola downwarp. Its orientation coincides with the direction of stress arising from closure of the Iapetus Ocean and collision in Scandinavia. As a result the sedimentary complex filling this downwarp did not experience complete folding. It was deformed only in zones of regional wrench faulting, as proposed already by Harland back in 1964.
The practical significance of the results discussed here consists of the fact that in the southwest part of the Barents Sea there is a thick Lower Paleozoic section that is not deformed. It is partly or completely in the oil window and has not exhausted its generating potential. It is underlain by Riphean sedimentary units that contain significant concentrations of organic matter at lower stages of catagenesis. Oil shows have been found on Spitzbergen, on the Rybachi Peninsula at the northwest end of the Kola Peninsula, and in the Pechora sineklize. On a basis of the information presently available the entire Central Barents high is assessed as favorable for petroleum in the Lower Paleozoics.
The passive character of collision processes on the Arctic shelves during the entire Phanerozoic has been a determining factor in the high petroleum potential there.
Taken from Verba and Ivanova, 2000; digested in Petroleum
Geology, vol. 36, no. 2, in preparation, two maps, one cross section.
Copyright 2002 James Clarke. You are encouraged to print out this
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