Geological Significance and Geochronology of Paleoproterozoic Mafic Dykes of Xiaoqinling Gold District, Southern Margin of the North China Craton
详细信息
- 责任者：Bi Shijian (State Key Laboratory of Geological Processes and Mineral Resources ; China University of Geosciences ; Wuhan 430074 ; China) ; Li Jianwei
- 刊名：Earth Science
- 出版年：2011
- 卷期：36(1)
- 关键词：金矿 ; gold ores ; 石英脉型矿床 ; quartz veins type deposit ; 秦岭 ; Qinling Mountains
- 页码：p.17-32
- 图表：7 illus., 2 tables, 63 refs.
- 分类号：1001
- issnNo：ISSN1000-2383
- isbnNo：CN42-1233/P
摘要
In this paper, the authors present LA-ICPMS zircon U-Pb and biotite 40Ar-39Ar ages of four mafic dikes samples collected from three major gold deposits (Dongchuang, Dahu and Qiangma deposits) in the Xiaoqinling gold district, southern margin of the North China Craton. The results suggest that: 1) numerous mafic dikes in the Xiaoqinling gold district formed in Paleoproterozoioc, in an extensional setting after the collision between the eastern and western blocks of the North China craton at ca. 1.85 Ga; and 2) previous whole rock K-Ar and Rb-Sr ages (187.6~75.9 Ma) which are significantly younger than our ages represent thermal perturbation (or cooling ages) caused by Mesozoic tectonic-thermal event. Recent geochronological studies show that the majority of gold deposits formed in Early Cretaceous (130~120 Ma) in the Xiaoqinling district. Therefore, the mineralization event had no relationship with Paleoproterozoic mafic dykes although they were spatially associated.