SHRIMP U-Pb zircon dating of the Pan-African granite in Baxoi County, eastern Tibet, China

The Kaqiong fine-grained biotite-alkali feldspar granite exposed in the Tonggar area, Baxoi County, eastern Tibet, is Pan-African granite that was for the first time found in eastern Tibet. The Kaqiong Group-complex is composed of granite, granite gneiss, biotite plagiogneiss, marble, biotite-plagioclase fine-grained gneiss and retrograded eclogite. It is the main part of the Kaqiong microblock that occurs as a sheet sandwiched between the Bangong Co-Nujiang suture zone. The Kaqiong fine-grained biotite-alkali feldspar granite, which has a SHRIMP U-Pb zircon age of 507±10 Ma, is the record of magmatic activity during Pan-African orogeny and further verifies that the area south of the Bangong Co-Nujiang suture is the Pan-African basement. This study provides new information for the tectonic evolution of the southern Qinghai-Tibet plateau.