LA-ICP-MS Zircon U-Pb Age of Granitic Mylonite in The Gaoligong Shear Zone of Western Yunnan Province and Its Tectonic Significance

详细信息   

• 责任者：Li Zaihui (Chengdu Institute of Geology and Mineral Resources ; China Geological Survey ; Chengdu 610081 ; China) ; Wang Liquan
• 刊名：Geological Bulletin of China
• 出版年：2012
• 卷期：31(8)
• 关键词：糜棱岩 ; mylonite ; 铀—铅计时 ; U-Pb dating ; 云南 ; Yunnan Province
• 页码：p.1287-1295
• 图表：4 illus., 2 tables, 52 refs.
• 分类号：0802
• issnNo：ISSN1671-2552
• isbnNo：CN11-4648/P

摘要

The NS or NE-SW trending Gaoligong metamorphic belt lying in southwest Yunnan Province is distributed along west Gaoligongshan strike-slip shear zone. In this paper, U-Pb zircon dating was carried out by using LA-ICP-MS for granitic mylonite from the Gaoligongshan shear zone. It yielded the weighted average age of (41.9±1.0) Ma from magma zircons and that of (38.4±2.1) Ma from the metamorphic overgrowth rims of zircon, respectively. Combined with regional geological background, geological evolution, rock fabric and geochronological data, this paper has drawn the conclusion that the granitic mylonite was crystallized at 42Ma and underwent mylonitization at 38 Ma, indicating that the Gaoligong strike-slip shear zone was active as a dextral strike-slip shear zone at least from 38 Ma.