Выпуск 48
Автор(ы):Buslov M.M., Dobretsov N.L.
Издание:Russian Geology and Geophysics, 2007 г., 12 стр.
Late Cambrian-Ordovician tectonics and geodynamics of Central Asia

In the Late Cambrian-Ordovician, Gondwana-derived microcontinents such as Kokchetav, Altai-Mongolian, Tuva-Mongolian, and Barguzin, as well as the Kazakhstan-Tuva-Mongolian island arc or a system of island arcs were involved in intense accretion-collision processes in similar geodynamic settings on a vast territory of Central Asia — from West Kazakhstan to Lake Baikal. The processes were likely to be the result of a large rebuilding of the Earth’s crust possibly related to the increased mantle impact on the lithosphere as they were simultaneous to the opening of the Uralian and Mongolian-Okhotsk (Turkestan) Oceans. The 970–850 Ma breakup of Rodinia and the 760–700 Ma important tectonic events were followed by the Late Cambrian-Early Ordovician plume magmatism impulse at 500–480 Ma, which led to the opening of new oceans and accelerated the accretion of the Gondwana-derived blocks to the island arc and subsequent formation of an extended — more than 6000 km long — Kazakhstan-Baikal orogenic belt.

ТематикаРегиональная геология
Автор(ы):Akiyama M., Buslov M.M., Iwata K., Saphonova I.Yu., Travin A.V., Watanabe T.
Издание:International Association for Gondwana Research, 2002 г., 20 стр.
A Vendian-Cambrian Island Arc System of the Siberian Continent in Gorny Altai (Russia, Central Asia)

An extended Vendian-Cambrian island-arc system similar to the Izu-Bonin-Mariana type is described in the Gorny Altai terrane at the margin of the Siberian continent.

Three different tectonic stages in the terrane are recognized. (1) A set of ensimatic active margins including subducted oceanic crust of the Paleo-Asian ocean, the Uimen-Lebed primitive island arc, oceanic islands and seamounts: the set of rocks is assumed to be formed in the Vendian. (2) A more evolved island arc comprising calc-alkaline volcanics and granites: a fore-arc trough in Middle-late Cambrian time was filled with disrupted products of pre-Middle Cambrian accretionary wedges and island arcs. (3) Collision of the more evolved island arc with the Siberian continent: folding, metamorphism and intrusion of granites occurred in late Cambrian-early Ordovician time. In the late Paleozoic, the above-mentioned Caledonian accretion-collision structure of the Siberian continent was broken by large-scale strike-slip faults into several segments. This resulted in the formation of a typical mosaic-block structure.

ТематикаРегиональная геология
МеткиCentral Russia, Eclogite, Gorny Altai, Island arc, Paleo-Asian ocean, Алтай, Палеоазиатский океан, Эклогиты
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