• 责任者：Xie Jincheng (State Key Laboratory of Geological Processes and Mineral Resources ; China University of Geosciences ; Beijing 100083 ; China) ; Li Weikai
• 刊名：Acta Petrologica Sinica
• 出版年：2013
• 卷期：29(11)
• 关键词：花岗岩 ; granite ; 岩石地球化学 ; lithogeochemistry ; 西藏 ; Tibet
• 页码：p.3779-3791
• 图表：11 illus., 3 tables, 31 refs.
• 分类号：0801
• issnNo：ISSN1000-0569
• isbnNo：CN11-1922/P

     Tibet Basu area lies in the northeast of Gangdese-Nyainqentanglha block, being close to Bangong Co-Nujiang suture zone. There are many granitic intrusions, including granodiorite and granitite, invading into volcanic rocks of Zhucun Formation. Only regional geological survey of 1 ： 250 thousands scale has been conducted in the study area, and the genesis of these rocks have been poorly studied, especially the granite. This article, based on the detailed field investigation, has studied the petrology, geochemistry and geochronology in order to define the tectonic significance of the granitoids. LA-ICP-MS zircon U-Pb age dating indicates that the granodiorite and quartz-diorite were emplaced at ca. 119. 7 ± 1.2Ma and ca. 120. 6 ± 1.8Ma. The zircon εHf（t） values（ - 10. 42 -7.00） yields zircon Hf crustal modal age of 1624 - 1841Ma. Geochemical characteristics indicate that these rocks are from partial melting of the crust, exchanging with mass and heat flow from the mantle. It was induced that the rocks were formed under the background of slab subduction. The Zhucun Formation volcanic rocks in the northeastern part of the intrusions gave a SHRIMP zircon U-Pb age of ca. 128 ± 2Ma, indicating that these hornblende dacites were formed in a same magmatie event and emplaced at ca. 9Myr earlier than the granitic rocks. Therefore, the Basu granites together with those volcanic rocks were formed under a subducted background of the Nujiang Oceanic crust subducted into Gangdese-Nyainqentanglha block.