MODERN STRUCTURE OF THE URALS AS A RESULT OF THE POSTPALEOZOIC EXTENSION OF THE EARTHS CRUST

Authors
Citation
Ks. Ivanov, MODERN STRUCTURE OF THE URALS AS A RESULT OF THE POSTPALEOZOIC EXTENSION OF THE EARTHS CRUST, Geologia i geofizika, 39(2), 1998, pp. 204-210
Citations number
32
Categorie Soggetti
Geosciences, Interdisciplinary
Journal title
ISSN journal
00167886
Volume
39
Issue
2
Year of publication
1998
Pages
204 - 210
Database
ISI
SICI code
0016-7886(1998)39:2<204:MSOTUA>2.0.ZU;2-U
Abstract
The Urals structure, as a whole, is the result of the post-Permian sub latitudinal extension of the region. It is characterized by alternatin g submeridional zones: synform zones made up of nonmetamorphosed volca nogenic and sedimentary series and the antiform ones comprised of deep metamorphic and intrusive complexes. The boundaries between these zon es are large faults, which usually descend at angles of 30-50 degrees to less metamorphosed rocks. These faults are mainly normal faults whi ch appeared as a result of the Earth's crust extension, but not overth rusts, as was considered earlier. These young faults developed primari ly in tectonically weak zones of the older thrusts and detachment zone s which were present between the upper (brittle) and middle (plastic) crust. Exhumation of megablocks of the high-grade rocks formed in the lower and middle crust occurred as a result of their uprise to the upp er crust during the rupture and extension of the latter. The extension began, evidently, in the Early Triassic. The South Urals structure al ong the Kumertau-Nikolaevka profile is described. A new important tect onic stage - post-collision extension - has been determined in the geo logical history of the Urals.