Early-Middle Ordovician nappe tectonics of the junction between the Kokchetav HP-UHP metamorphic belt and the Stepnyak paleoisland arc (northern Kazakhstan)

Zhimulev F.I.; Buslov M.M.; Travin A.V.; Dmitrieva N.V.; De Grave J.

doi:10.1016/j.rgg.2010.12.009

Инд. авторы:	Zhimulev F.I., Buslov M.M., Travin A.V., Dmitrieva N.V., De Grave J.
Заглавие:	Early-Middle Ordovician nappe tectonics of the junction between the Kokchetav HP-UHP metamorphic belt and the Stepnyak paleoisland arc (northern Kazakhstan)
Библ. ссылка:	Zhimulev F.I., Buslov M.M., Travin A.V., Dmitrieva N.V., De Grave J. Early-Middle Ordovician nappe tectonics of the junction between the Kokchetav HP-UHP metamorphic belt and the Stepnyak paleoisland arc (northern Kazakhstan) // Russian Geology and Geophysics. - 2011. - Vol.52. - Iss. 1. - P.109-123. - ISSN 1068-7971. - EISSN 1878-030X.
Внешние системы:	DOI: 10.1016/j.rgg.2010.12.009; SCOPUS: 2-s2.0-78650776726;
Реферат:	eng: The North Kokchetav tectonic zone is located between the Kokchetav HP-UHP metamorphic belt and the Stepnyak zone of Ordovician island arc and oceanic complexes. The Kokchetav zone is a collage of nappes (thrust sheets) that consist of basement gneiss and sedimentary rocks of the Kokchetav microcontinent, granite gneiss, mica schists with eclogite blocks, the Shchuch'e ophiolite, Middle Proterozoic felsic volcanics, and Arenigian siliceous-terrigenous sediments with olistostromes. The latter are of gravity-sliding origin and their clastic material includes quartz-muscovite and quartz-garnet-muscovite schists, gneiss, dolomite, and amphibolite. The sheet boundaries are marked by mylonite and Early Ordovician mica schists (40Ar/39Ar ages of syntectonic muscovite are 489-469 Ma). The North Kokchetav collage of compositionally diverse thrust sheets can be interpreted as a collisional zone. According to geological evidence, tectonic activity in the zone lasted as late as the Middle Ordovician. Syncollisional thrusting in the North Kokchetav zone was coeval with the latest dynamic metamorphic event in the Kokchetav belt. All events of retrograde metamorphism and exhumation of HP and UHP rocks in the belt have Cambrian ages, i.e., the rocks had been exhumed prior to the Early-Middle Ordovician collisions and the related orogeny. © 2010.
Ключевые слова:	thrust; tectonic setting; sedimentary rock; schist; retrograde metamorphism; orogeny; Ordovician; nappe; metamorphic rock; island arc; gneiss; ultrahigh pressure metamorphism; continental collision; Cambrian; Thrust sheet; Olistostrome; North Kokchetav tectonic zone; Kokchetav metamorphic belt; High-pressure rocks; Exhumation; Early Paleozoids of Kazakhstan; Collision; 40Ar/39Ar dating; exhumation;
Издано:	2011
Физ. характеристика:	с.109-123