Formation History of the Tuva-Mongolian Massif (Western Hubsugul Region, North Mongolia) Based on U-Pb Dating of Detrital Zircons from Sandstone of the Darkhat Group by the LA-ICP-MS Method

摘要

The Tuva—Mongolian Massif was defined in 1971 as a block with an Early Precambrian basement and Vendian-Cambrian carbonate cover of the platform type [1]. Subsequently, the contours of the massif were changed substantially and its dimensions were reduced [2]. The present-day boundaries correspond to the contour outlining the distribution area of the Vendian—Cambrian carbonate cover [3, 4] (Fig. 1). In the south, the Tuva—Mongolian Massif is separated by a fault from the Dzabkhan Massif. Formerly, these two massifs formed a single block, which is evident from the development of similar carbonate rocks in their covers [3]. In this connection, the validity of the Tuva-Mongolian Massif as a geological structure that developed against the background of surrounding younger Paleozoic complexes is beyond doubt [5]. The age of blocks constituting the basement of the massif, as well as the history of their amalgamation and relation with other blocks, remains insufficiently known despite the availability of many special publications dedicated to these aspects [2-4,6-9].