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A Vendian-Cambrian Island Arc System of the Siberian Continent in Gorny Altai (Russia, Central Asia) |
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| Authors: | MM Buslov T Watanabe IYu Saphonova K Iwata A Travin M Akiyama |
| Institution: | aUnited Institute of Geology, Geophysics and Mineralogy, Russian Academy of Sciences, Siberian Branch, 630090, Koptyuga ave. 3, Novosibirsk, Russia bDivision of Earth and Planetary Sciences, Graduate School of Science, Hokkaido University, 060-0810, Sapporo, Japan cConsulting Engineers I.N.A.Corporation, Bunkyo-ku, 112-8668, Tokyo, Japan |
| Abstract: | 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. |
| Keywords: | Paleo-Asian ocean island arc eclogite Gorny Altai Central Russia |
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