东川铜矿床同位素地球化学研究:I.地层年代与铅同位素化探应用

ISOTOPE GEOCHEMISTRY STUDY OF DONGCHUAN COPPER DEPOSITS IN MIDDLE YUNNAN PROVINCE, SW CHINA: I. STRATIGRAPHIC CHRONOLOGY AND APPLICATION OF GEOCHEMICAL EXPLORATION BY LEAD ISOTOPES

采用Ｐｂ－Ｐｂ等时线法测定了昆阳群中亚群落雪组白云岩、黑山组碳质板岩和上亚群大营盘组碳质板岩样品，获得了（１７１６±５６）Ｍａ、（１６０７±１２８）Ｍａ和（１２５８±７０）Ｍａ的年龄，确定了昆阳群中亚群时代约为１６００—１８００Ｍａ，属晚古元古代，上亚群大营盘组约为１２００—１３００Ｍａ，属中元古代。还应用铅同位素化探技术系统研究了汤丹铜矿１号硐中段西１４穿脉岩石－矿石的铅同位素组成，结果表明铅同位素Ｖ１值与铜含量呈反相关系。这是运用系统剖面方法开展铅同位素化探的首次尝试。

The Pb-Pb isochron dating for the strata of Kunyang Group yielded ages of (1716±56) Ma for the dolomites of the Luoxur Formation in the middle subgroup, (1607±128) Ma for the carbonaceous slates of the Heishan Formation in the middle subgroup and (1258±70) Ma for the carbonaceous slates of the Dayingpan Formation in the uooer subgroup,indicating the rocks of the middle subgroup formed in late Paleo-Proterozoic and the rocks of the upper subgroup formed in Middle Proterozoic. In addition, Pb isotope analysis along the field section has been applied to the exploration in the Tangdan copper deposit, Dongchuan, Yunnan Province, and it shows that there is a negative correlation betweenthe V 1 values of Pb isotope and Cu contents.