TIMING OF COLLISION OF THE KOKCHETAV MASSIF WITH THE STEPNYAK ISLAND ARC ON THE BASIS OF CONODONTS AND RADIOLARIANS FROM SILICEOUS ROCKS OF JUXTAPOSED TERRANES OF DIFFERENT GEODYNAMIC SETTINGS
O.T. Obut, M.M. Buslov*, and K. Iwata**, and F.I. Zhimulev
Institute of Petroleum Geology and Geohysics, Siberian Branch of the RAS,
3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
* Institute of Geology and Mineralogy, Siberian Branch of the RAS,
3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
** University of Hokkaido, Department of the Earth and Planet Sciences, 060-0810, Sapporo, Japan
Keywords: Collision, olistostrome, thrust, conodonts, Kokchetav massif
Pages: 451-457
Abstract
The siliceous rocks from structures of the junction zone of the Kokchetav massif and Stepnyak trough that occur in turbidites of the accretionary wedge, silica-volcanogenic sequence of the Stepnyak trough and syntectonic olistostrome were dated on the basis of findings of conodonts and radiolarians within the Middle-Upper Arenigian (conodont zones O. evae, B. navis-lower Par. originalis). This range of time is marked by a powerful tectonic rearrangement, involved with the rearrangement of the accretionary wedge and overriding of the Kokchetav massif upon the Stepnyak fore-arc trough.
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