Three structural stages are recognized in the region of the Barents Sea: basement, intermediate platform, and upper basin. The intermediate stage is the lower, largely carbonate complex below marker reflecting Horizon Ia. Reference Horizon I is used to describe the configuration of the structural features because this marker tracks so well over such a large area. These features do not correspond everywhere exactly with structures on the basement surface.
The Barents mega-trough extends from Norway to Franz Josef Land, a distance of 1200 km. Components are the Nordkapp downwarp, West Kola saddle, South Barents depression, Ludlov arch, and North Novaya Zemlya downwarp. Corresponding with this structural low is a zone beneath a thin layer of Quaternary sediments in which seismic velocity is relativerly low at 2.0-2.5 kmps.
Thickness of the upper structural stage is 4-6 km in Nordkapp downwarp, 9-10 km in North Novaya Zemlya downwarp, and about 12 km in South Barents depression.
The Central Barents high coincides with a shallow-water area of the Barents Sea. Here the upper clastic complex (upper structural stage) is thin at 1.5 km or less, and seismic velocities in the sub-Quaternary rocks are 2.5-3.7 kmps. Individual anti- clinal flexures are present here as well as faults. Dips are up to 4-6 degrees. Central Barents high along with Perseus high to its north form a large arch bounding the Barents mega-trough on the west. This arch is separated from the Svalbard high by the Medvezh-Olga depression.
In Medvezh-Olga depression the sea-floor topography shows a depression. Seismic velocities of the pre-Quaternary sediments are from 2.5 to3.35 kmps, which is somewhat lower than on Cen- tral Barents high. It is assumed that Upper Jurassic-Cretaceous sediments are present here at the sea-floor interface. Total thickness of the upper structural stage in this depression is 3-4 km. Four tectonic phases are recognized in the region.
The first phase includes the Early Paleozoic, Silurian, and Early Devonian. This was a taphrogenic stage wherein basement was broken into small blocks, and the blanketing sediments are uneven in composition and thickness.
The second phase was calm tectonically, extending from the latter half of the Devonian to the Early Permian. Carbonates of uniform thickness and composition were deposited.
The third phase was a time of active tectonism with formation of superimposed troughs. It extended from Early Permian to Early Cretaceous time.
The fourth phase is Cenozoic and continues today. Domal uplifts have developed, and the orogens along the borders of the Barents Sea have been uplifted.
Taken from Verba, 1984, one tectonic map and three cross
sections; digested in Petroleum Geology, Vol. 23, No. 5/6.
Copyright 2003 James Clarke. You are encouraged to print
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I do not know what I may appear to the world, but to myself I seem
to have been only like a boy playing of the seashore, and diverting
myself in now and then finding a prettier shell or a smoother pebble
than ordinary, whilst the great ocean of truth lay all undiscovered
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