Tectonic Map of Earth’s Polar Regions and Some Aspects of Comparative Analysis1
Published:January 01, 1973
B. Kh. Egiazarov, I. P. Atlasov, M. G. Ravich, G. E. Grikurov, R. M. Demenitskaya, G. Z. Znachko-Yavorsky, A. M. Karasik, Yu. N. Kulakov, A. P. Puminov, B. S. Romanovich, 1973. "Tectonic Map of Earth’s Polar Regions and Some Aspects of Comparative Analysis", Arctic Geology, Max G. Pitcher
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The “Tectonic Map of the Polar Regions of the Earth” has been compiled on the scale 1:10,000,000, and structural regions have been distinguished on the basis of genesis and age. The map is accompanied by sketches of geotectonic zonation, neotectonic data, and geophysical characteristics reflecting deep features of the Arctic and Antarctic regions.
The North and South Polar regions have had different histories since Proterozoic time, and their deep-seated structures differ. The Arctic and Antarctic, although both are regions where the Pacific and Atlantic structural segments join, did not have similar géosynclinal and tectono-magmatic development.
In the Arctic, the stable Precambrian platform underwent fragmentation which gave rise to smaller platforms and central stable regions fringed by fold systems such as the Baykalides, Caledonides, Hercynides, and Mesozoides. The asymmetrical structure of the Arctic is evidenced by the differing degrees of stability of its western and eastern segments. The Antarctic, in contrast to the North Polar region, represents a heterogeneous pre-Riphean platform of a Gondwana type similar to the platforms of Africa, South America, Australia, and India. In West Antarctica the platform is fringed by the Antarctandes, which belong to the Pacific mobile belt. The Archean and Proterozoic mag-matic complexes of the two Polar regions are almost the same type. The Antarctic is characterized by a widely developed charnockite formation.
The earth's crust in the Arctic is of complex structure and greatly varied thickness. In the Arctic basin, three areas may be distinguished: “normal ocean,” transoceanic ridge area (Lomonosov and Mendeleyev-Alpha ridges), and the Canada basin. The Antarctic continent has mainly continental crust, but subcontinental crust is present at the West-East Antarctica juncture. The South Ocean is underlain by oceanic crust with some complications within the submarine ridges.
It is postulated that the thickness and crustal structure have changed abruptly in the Arctic during geologic history but were more stable in the Antarctic. The youngest tectonic event is marked by reactivation of structural features which determine the modern relief forms. Block movements are significant in the Antarctic. Besides these movements of opposite sense, a concentric distribution of the main structural features about the geographic poles is apparent in the polar regions.
Figures & Tables
Following the discovery of Prudhoe Bay oil field in 1968, much attention was turned to the Arctic in the search for giant hydrocarbon accumulations. The Soviets had already proved giant reserves in their West Siberian Basin, and exploration was moving ahead quickly in the Canadian Arctic. Plans were drawn up for an AAPG Symposium on Arctic Geology and held in February 1971. Papers were selected from the Symposium for this publication and cover seven topical groupings: Regional Arctic Geology of Canada, Regional Arctic Geology of the Nordic Countries, Regional Arctic Geology of the USSR, Regional Arctic Geology of Alaska, Comparisons in the North Atlantic Borders, Evolution of the Arctic Ocean Basin, and Economics of Petroleum Exploration and Production in the Arctic.