Charakteristika a časový vývoj paleozoického akrečního systému v jižním Mongolsku

Sukhbaatar, Turbold

The microcontinental fragments in central Mongolia are represented by the series of Precambrian blocks consisting of the Baidrag, Zavkhan, Tuva-Mongol, and Tarvagatay blocks forming the so-called Central Mongolian Massif. The Baidrag Block (BB), the southernmost part of the Central Mongolian Massif, records long-lasted evolutionary events of the Central Asian Orogenic Belt. During the Neoproterozoic, the BB had been rifted apart from the Rodinia taking part of the ribbon-like microcontinental block surrounded by the oceanic basins and facing the external Palaeo-Pacific oceanic domain. Our findings suggest the existing oceanic domain north of the BB was subducted and closed in Ediacaran times. For instance, the northern part (in today's coordinate) of the BB is linked to the Cryogenian Bayankhongor oceanic basin (ca. 636--655 Ma) which was considered to be an exclusively reflecting sea- floor section. However, our data support a new interpretation that the Bayankhongor Zone is not entirely consisting of seafloor sequences. According to these findings, southwest-directed Ediacaran (ca. 564--598) subduction of the oceanic plate beneath the Baidrag Block is proposed. In southwestern Mongolia, the important events of the late Neoproterozoic to upper Paleozoic continental growth are recorded. The...

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