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The AAPG/Datapages Combined Publications Database

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Abstract


Pub. Id: A108 (1973)

First Page: 189

Last Page: 193

Book Title: M 19: Arctic Geology

Article/Chapter: Main Features of Geologic Structure of Eastern USSR and Contiguous Territories: Regional Arctic Geology of the USSR

Subject Group: Geologic History and Areal Geology

Spec. Pub. Type: Memoir

Pub. Year: 1973

Author(s): L. I. Krasny (2)

Abstract:

Three geochrons are distinguished: (1) Protogey (before 1,600 m.y.), (2) Mesogey (1,600-600 m.y.), and (3) Neogey (younger than 600-550 m.y.).

Within the Aldan and Sino-Korean shields, the oldest volcanic regions and primary uplifts (e.g., Yendyr') are present. After consolidation of the early Archean mobile regions in the protogeosynclines, the Stanovoy fold system formed. Later, around 1,900-1,800 m.y. ago, a gigantic collapse (Einbruch) took place. During the last 300 m.y. of the Protogey geochron, large basins developed.

During the 1,000 m.y. that composed the Mesogey geochron, a calm, catastable regime predominated. At the beginning and at the end of the Mesogey, volcanic activity was intense (El'gete volcanism).

Five stages of the Neogey geochron are distinguished: (1) early Paleozoic, during which broad geosynclines, filled mainly with terrigenous and carbonate sediments, and late Baykalian structures associated with broad granitoid magmatism formed; (2) middle Paleozoic, during which thick eugeosynclinal and miogeosynclinal sequences subsided; (3) late Paleozoic, during which subsidence continued and the Mongolo-Okhotsk, Sikhote-Alin, and Nippon (Japan) systems were rebuilt; (4) Mesozoic--especially significant in the eastern USSR--during which various types of mobile regions and systems developed (Verkhoyansk and Chukotsk geosynclinal systems, Mongolo-Okhotsk system, Selengino-Yablonovyy and Stanovoy regions of mountain uplift and block faulting and formation of the Jurassic-Cretaceous rif basin; the Chugoku, Eastern Sikhote-Alin, Okhotsk-Chukotsk, and Nunivak [Alaska] volcanic belts; and the Simanto orthogeosynclinal belt); (5) Cenozoic, during which intense mountain building was accompanied by evolution of intermontane basins on continents and formation of systems of island arcs in a transitional region of continent-ocean (Kuril-Kamchatka and Aleutian systems). During this time, an accelerated rate of tectonic processes apparently existed.

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