Main Structural Features of Arctic: ABSTRACT

The fold belts of northern Greenland, Arctic Canada, northern Alaska, Chukotsk, and the Siberian Arctic coast (to the mouth of the Lena River) form the latitudinal Arctic belt of Baikalides, Caledonides, Hercynides, and Mesozoides. The spatial location of the Arctic belt was determined by the Hyperboreal and Greenland-Canadian platforms, and by the center of the Yukon, Anadyr-Seward, and Kolyma massifs at the close of the Proterozoic and the beginning of the Paleozoic. It is suggested that the fold belts of the Arctic belt--according to their geographical position, structural framework, style, and type of development--be isolated as a special geostructural zone of the earth (the Arctides) and the Atlantic segments (the Atlantides). The Arctides are characterized mainly by a miogeosynclinal sedimentation regime; the eugeosynclinal regime is characteristic of the Pacifides. The Arctides may be divided into two segments: Euramerasian (from eastern Greenland to the Mackenzie District) and Amerasian (from Mackenzie to the Lena River), which differ from each other by the ages of the fold systems. These differences emphasize the asymmetric structure of Arctides. The Caledonian and Hercynian folding systems are developed in the Euramerasian segment. The Mesozoic geosynclinal cycle played the main role in the Amerasian segment (the Mesozoides of the northern Alaska and Novosibirsk-Chukotsk fold systems). The junction of the Arctides and Pacifides occurs along the zone of the Mackenzie-Lena latitudinal and sublatitudinal deep faults. The nature of the Arctides junction with the folding systems of Taimyr, Severnaya Zemlya, Novaya Zemlya, and Spitsbergen is not clear. Hypothetically, this deep-lying border may be drawn along the continental slope from Greenland to the mouth of the Lena. The great Kolyma megablock (Kolyma massif, and the Verkhoyansk and eastern Amur Mesozoides bordering the massif), limited by the zones of deep-seated faults, exhibits the mutual influence of the Arctic and Pacific structural styles and tectonic types of development. It is suggested that this megablock be considered as a transitional geostructural area--the Arctopacifides. It is suggested that the western Arctic (i.e., Taimy, Severnaya Zemlya, and Novaya Zemlya fold area; fold structures of Timan, Spitsbergen, and eastern Greenland; and the area bordering the Barents Sea platform and the Kara Sea massif) that is spatially and genetically associated with the Atlantic segments and occupies the intermediate position between the Atlantides and Arctides be assigned to another transitional area--the Arcto-Atlantides. End_of_Article - Last_Page 2509------------