Zircon U-Pb age and geochemical characteristics of the volcanic rocks in the Dianzhong Formation of the Geda area in the middle of the Gangdise

The Linzizong Group volcanic rocks are widespread in the southern part of the Qinghai-Tibet Plateau and the geological information of the Neo-Tethys subduction and the collision of Indian-Asian plate was recorded in those volcanic rocks. The LA-ICP-MS U-Pb isotope dating of zircon and geochemical characteristics of whole rocks were studied to investigate the formation age, magma source and tectonic environment in the Dianzhong Formation of the Geda area in middle of the Gangdise. The ages of LA-ICP-MS U-Pb dating of zircon from the volcanic rocks of Dianzhong Formation is (61.6±1.0) Ma. These volcanic rocks are charactered by rich LILE and LREE, and poor HFSE, with typical island arc characteristic. These volcanic rocks were mainly derived from the partial melting of crustal material, which were the formed in an island arc environment during the northward subduction of the Neo-Tethys ocean.