Discovery of the Mid-Late Jurassic Songmuguo strongly peraluminous granite belt in the southern part of Nyima County, Tibet, and its significance

Abstract：A strongly peraluminous (SP) granites belt, extending over 100 km from east to west, is distributed 800-100 km south of the Bangong Co-Nujiang junction zone. It consists of several intrusions such as the Songmuguo intrusion and Yangxiongle intrusion. The intrusions are emplaced on both south and north sides of the Ngangzê Co-Sereba fault and involve five intrusion events. They all belong to high-K, calk-alkaline, SP granites and are post-collisional SP granites of Mid-Late Jurassic age. Study suggests that the formation of the belt is related to the southward subduction and closing of the Nyima segment of the Bangong Co-Nujiang junction zone before the Middle Jurassic. The limited length of the SP granite belt and its earlier regional emplacement time show that the Meso-Tethys is composed of multiple blocks and closed in different times.