Zircon SHRIMP U-Pb Age of Jinkouhe Diabase Dykes in Ebian Area of Western Sichuan Province and Its Implications for the Breakup of Rodinia

详细信息   

• 责任者：Cui Xiaozhuang (Chengdu Center ; China Geological Survey ; Chengdu 610081 ; China) ; Jiang Xinsheng
• 刊名：Geological Bulletin of China
• 出版年：2012
• 卷期：31(7)
• 关键词：辉绿岩 ; diabase ; 四川 ; Sichuan Province
• 页码：p.1131-1141
• 图表：5 illus., 2 tables, 62 refs.
• 分类号：0801
• issnNo：ISSN1671-2552
• isbnNo：CN11-4648/P

摘要

There are abundant mafic dykes that intruded the Mesoproterozoic Ebian Group in Jinkouhe area of western Sichuan Province. Their precise emplacement time is significant for revising the time of the Ebian Group and studying the Precambrian tectonic setting of the western margin of Yangtze Craton. One of the diabase dykes from Jiadanqiao Formation of Ebian Group was dated by SHRIMP zircon U-Pb dating. The result shows that the zircons are of typical mafic magmatic origin with clear and wide internal growth zoning and high Th/U ratios, and the weighted mean ²⁰⁶Pb/²³⁸U age is（813.4±8.2） Ma （MSWD=0.56）. This result represents the emplacement time of the diabase dykes, and also constrains the minimum age of Jiadanqiao Formation in Ebian Group.