浙江建德岭后铜矿磁黄铁矿Re Os年代学 特征及成矿意义

浙江建德岭后铜矿床位于扬子板块与华夏板块之间的钦杭结合带的北东段，矿化主要发育于中石炭统黄龙组下段灰质白云岩中及花岗闪长斑岩侵入体与其接触带上。挑选块状铜矿体中的磁黄铁矿进行Re Os同位素年代学研究，获得等时线年龄为121±12Ma和122.5±8.7Ma。结合前人的研究成果及本次的年代学研究，认为岭后铜矿是在古生代海底喷流成矿作用的基础上受到中生代岩浆作用的改造、富集而形成的，是海底热水沉积—热液叠加改造型矿床。中生代的热液叠加成矿作用受到华南地区岩石圈伸展、减薄作用的影响，是中国东部燕山期第三次大规模成矿作用的结果。本次研究也为在浙江西部地区寻找与中生代岩浆活动有关的成矿作用提供了证据。

Re Os Isotopic Dating of Pyrrhotite in the Linghou Cu Deposit, Jiande, Zhejiang Province and Its Geological Significance

The Linghou Cu deposit is located in the northeastern part of the Qinghang metallogenic belt which is bordered between Yangtze plate and Cathaysian plate. Mineralization occurs mainly in limy dolomite of lower Huanglong Formation of Carboniferous Series and the contact zone between granodiorite porphyry with dolomite. Pyrrhotites in massive Cu beaing bodies were selected for Re Os dating, yielding isochronal ages of 121±12Ma and 122.5±8.7Ma. The ages obtained are consistent with the formation age of the Yanshanian intrusion in the ore district, which indicates close relation between mineralization and the intrusive rocks. Combined with the previous reseaches and Re Os age obtained in this study, it can be concluded that the Linhou Cu deposit is a submarine hydrothermal sedimentary hydrothermal reformation deposit which resulted from a Paleozoic submarine exhalative sedimentary metallogenesis due to reconstruction and enrichment of the Mesozoic magmatism. The metallogenesis of Mesozoic magmatism, which was affected by the lithosphere extension and thinning of the South China Craton, was the result of the third large scale metallogenesis in Eastern China during the Yanshanian. This study also provides some evidence for exploring the deposits of such kind (related to the Mesozoic magmatism) in the western Zhejiang provoince.