Zircon U-Pb Dating of Granite Xenolith from the Liuhe Syenite Porphyry from Yunnan Province, and Its Geologic Significance

详细信息   

• 责任者：Zhao Fufeng (Institute of Earth Science ; Chengdu University of Technology ; Chengdu 610059 ; China) ; Liu Xianfan
• 刊名：Acta Geologica Sinica
• 出版年：2011
• 卷期：85(10)
• 关键词：花岗岩 ; granite ; 正长斑岩 ; syenite porphyry ; 铀—铅计时 ; U-Pb dating ; 云南 ; Yunnan Province
• 页码：p.1574-1584
• 图表：6 illus., 2 tables, 46 refs.
• 分类号：0801
• 出版序号：20122327
• issnNo：ISSN0001-5717
• isbnNo：CN11-1951/P

摘要

///The Jinshajiang-Ailaoshan faulting belt in western Yunnan Province were found to host the Cenozoic alkali-rich porphyries, of which the Liuhe syenite porphyry contains granite xenolith paragenetically associated with deep mafic and ultramafic xenoliths. CL imaging LA-ICP-MS U-Pb dating and trace element analysis for the zircon from granite xenoliths conducted were conducted in this study. The results show that the zircons in the xenoliths contain three types: 1) magmatic zircons, compound magmatic zircons with old cores and new growth zones, and metamorphic zircons; 2) the old core has an average weighted age of (828.1±7.1) Ma, which represents the age of basal rock; and 3) the metamorphic zircons have an average weighted ²⁰⁶Pb/²³⁸Pb age of (108.4±4.4) Ma, which is consistent with the age （102.87±1.19 Ma） of amphiboled flogopite garnet bistagite and represents the crystallization age of mantle fluid metasoatism.