Paper No. 183-0
STRUCTURE AND THERMOCHRONOLOGY OF THE SOUTH VERKHOYANSK THRUST BELT, EASTERN SIBERIA
TORO, Jaime1, PROKOPIEV, A. V.2, MILLER, Elizabeth L.3, and DUMITRU, T. A.3, (1) Department of Geology and Geography, West Virginia Univ, 425 White Hall, PO Box 6300, Morgantown, WV WV26506-6300, jtoro@wvu.edu, (2) Laboratory of Tectonics, Diamond and Precious Metal Geology Institute, 39, Lenin Avenue, Yakutsk, 677891, Russia, (3) Geological and Environmental Sciences, Stanford Univ, Bldg 320, Lomita Mall, Stanford, CA 94305-2115

The Verkhoyansk fold and thrust belt of eastern Siberia extends for 1500-km from the Laptev Sea to the Sea of Okhotsk. It involves more than 7 km of Late Precambrian and Early Paleozoic shelfal strata, and a great thickness of intensely deformed Ordovician to Triassic basinal strata deposited along the paleo-Pacific margin of the North Asian craton. This margin developed as a consequence of rifting events in the Late Precambrian and in the Late Devonian to early Mississippian. Shortening in the fold and thrust belt took place during the Late Jurassic to Early Cretaceous. This deformation was accompanied by low-grade metamorphism in the internal parts of the belt, the emplacement of high-level granitic bodies, and foredeep subsidence in front of the north Verkhoyansk only. Deformation was likely due to collision with island arcs and small cratonal fragments.

Along the Allakh'-Yun River the southern Verkhoyansk is characterized by three distinct structural domains: 1) The frontal thrusts (Kyllakh domain) composed of four major west-vergent thrust sheets accounting for 18 km of displacement (70% shortening). The rocks involved are Late Proterozoic to Early Paleozoic platformal units. 2) A structural fan (Sette-Daban domain) within intensely deformed greenschist grade Cambrian to Silurian rocks of basinal origin. A poor quality151±1 Ma 40Ar/39Ar age from white mica offers the first constrain on the timing of metamorphism in the Sette-Daban. 3) An east-vergent zone (Allakh-Yun' domain) dominated by a thick and monotonous succession of Carboniferous and Permian turbidites metamorphosed to low-greenschist grade. Layering is generally tranposed by the west-dipping cleavage. Granodioritic plutons intrude in the core of the range and are associated with extensive gold-bearing quartz-vein systems. Cross-cutting relationships near that margin of the Tarbagganakh pluton (120 ± 1 Ma, 40Ar/39Ar, biotite) indicate that the pluton was emplaced during the waning stages of ductile deformation.

The overall structure of the South Verkhoyansk, with the oldest rocks exposed in the foreland and progressively younger, but more intensely metamorphosed units in the hinterland is determined by the inversion of the thick upper Paleozoic clastic wedge that lay a adjacent to the ancient Siberian margin prior to the onset of deformation.

GSA Annual Meeting, November 5-8, 2001
General Information for this Meeting
Session No. 183
Tectonics IV: Appalachian Tectonics- Evolution of Orogens
Hynes Convention Center: 200
1:30 PM-5:30 PM, Thursday, November 8, 2001
 

© Copyright 2001 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.