LA-ICP-MS U-Pb Dating of Detrital Zircons from Metaterrigenous Deposits of the Vendian-Cambrian Cover of the Tuva-Mongolian Microcontinent (Tunka Bald Mountains, East Sayan)

摘要

The northeastern segment of the Central Asian foldbelt (CAFB) contains ancient continental blocks; the largest of them are the Tuva-Mongolian (TMM) and Dzabakhan microcontinents. There is a fairly extensive isotope database for magmatic, metamor-phic, and sedimentary rocks of the Dzabakhan continental block, whereas most characteristics of the TMM were obtained for magmatic formations. Filling the lack in the study of sedimentary formations of the TMM, we studied detrital zircons of the Shu-mak Formation (Tunka bald mountains), which is one of the several preserved fragments of terrigenous sedimentation of nonglacial genesis within the shelf of this continental block.