Abstract:  The old continental crustal massifs or inlaid microcontinental blocks in the Central Asia Orogenic Belt characterize a previous PaleoMongolia ocean. Discussed in this work is the Xilinhaote microcontinental block. The Xilinguole complex—basement of the microcontinental block—has experienced the Early Paleozoic tectothermal events yet still contains older Precambrian zircons. The Xilinguole microcontinental block also acted as pillar when the orogenic belt suffered strong extensional deformation and underplating in the Late Paleozoic (C2P1): while rifts occurred at north and south edges of the microcontinental block, a stable littoralneritic facies sedimentary environment was maintained inside the block. At the same time, in the event of underplating from the upper mantle, tectonic structure of the orogenic zone remained stable, as the microcontinental block further accreted vertically and consolidated through certain orogenic bimodal magmatic activity and alkalic granite emplacement associated with block remelting. It has been the purpose of this work to comprehend some of the unique regional geological phenomena that are closely related to underplating during the Late Carboniferous.

Key words: microcontinental block, Central Asia Orogenic Belt, Late Paleozoic, consolidation, underplating