云南武定迤腊厂铜矿含矿石英脉^(40)Ar-^(39)Ar年龄及其意义

Ar-Ar ISOTOPIC AGE YINACHANG COPPER DEPOSIT, WUDING,YUNNAN PROVINCE, China AND ITS IMPLICATIONS

对武定迤腊厂铜矿成矿期石英进行了40Ar 39Ar同位素年龄测定,得到马鞍形年龄谱,坪年龄为(784 25±0 95)Ma,等时线年龄为(783 93±8 59)Ma。地质特征研究表明:该矿床后期改造作用明显,并非同生沉积或成岩作用早期成矿,而与晋宁期Rodina大陆裂解有关。武定迤腊厂铜矿的形成可能是在Rodinia大陆裂解时,从深部带来大量成矿物质,改造成岩时期初始的矿化,形成矿床的叠加富集和最终定位,晋宁 澄江期是该矿床的主成矿期。

The saddle-shaped age spectrum was founded by determining ^(40)Ar/^(39)Ar isotopic age of the Yinachang copper deposit. The result showed that the minerogenetic age is Jinningian (784 Ma). It is obvious that the deposit was reworked by later hydrothermal activities, not resultant from syngenetic mineralization or formed in the early stage of diagenesis. Its mineralization is related with the Jinningian break-up of the Rodinia continent. It is indicated that the Jinningian-Chunjiangian is the main mineralization stage of the Yinachang copper deposit, the abundant ore-forming materials came from the deep interior of the Earth and original mineralization occurred during the Jinningian-chunjiangian break-up of the Rodinia. It is very important for the ultimate localization of the Yinachang copper deposit.