Tectonic Map of Arctic Polar Regions of Earth: ABSTRACT

Abstract

The Tectonic Map of the Polar Regions of the Earth, scale 1:10,000,000, was compiled using the historic-genetic principle of distinguishing geostructural regions on the basis of genesis and age of their consolidation. The map is accompanied with sketches of geotectonic zonation, neotectonics, and geophysical characteristics reflecting deep features of the Arctic and Antarctic regions. The history of the earth's polar regions has changed since early Proterozoic time and the two regions differ with respect to their deep-seated structure. The Arctic and Antarctic, although they are regions where the Pacific and Atlantic geostructural segments join, did not have similar geosynclinal and tectono-magmatic development trends. In the Arctic, the stable Precambrian platform underwent fragmentation which gave rise to smaller platforms and central stable regions fringed by fold systems of Baikalides, Caledonides, Hercynides, and Mesozoides. Dissymmetry of the Arctic structure is outlined by a different degree of stability of its western and eastern segments. The earth's crust in the Arctic has a complex structure with major thickness changes. In the Arctic basin 3 types of areas can be distinguished: normal ocean, trans-ocean ridge area (Lomonosov and Mendeleyev Ridges, and the Sever Rise), and the Canada basin. The Antarctic, in contrast to the northern polar region, represents a heterogenetic 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 with Antarctandes belonging to the mobile Pacific belt. The magmatic complexes in the Archean and Proterozoic of the two polar regions are of almost the same type. The Antarctic is characterized by a widely developed charnokite formation. In the southern polar region, magmatism is predominantly inherited in character; the Andean intrusive complex (which is confined to the Antarctandes zone) is an exception. The Antarctic continent possesses continental and suboceanic crust within the west-east Antarctica zone of juncture. The Southern Ocean has oceanic crust complicated somewhat by submarine ridges. It is postulated that during the geologic past the thickness and crustal structure changed sharply in the Arctic but remained more stable in the Antarctic. The youngest tectonic event to affect the Antarctic was the reactivization of geostructural features that produced powerful block movements. Thus, the latest movements in the Arctic have been vertical, but downward. Those in the Antarctic were vertical, but upward. In addition to these movements of opposite sense, a concentric distribution of the main features of geostructures about the geographical poles can be seen in both polar regions. End_of_Article - Last_Page 2479------------