扬子地块南缘锑矿床中矿石铅的组成及其地质意义

锑是我国的特色矿产 ,扬子地块南缘锑矿带是世界上最大的锑成矿带。铅同位素研究表明 ,该带锑矿床中矿石铅的组成变化较大 ;在铅同位素组成图解中 ,线性分布明显 ,但它不具有等时线意义 ,而是由低放射性成因铅和高放射性成因铅两个端元混合所致。矿石铅属壳、幔混合铅。成矿作用应发生于开放体系之中 ,深部幔源物质可能参与了锑的成矿作用。

LEAD ISOTOPIC COMPOSITION OF ORES IN THE ANTIMONY DEPOSITS AT THE SOUTHERN MARGIN OF THE YANGTZE MASSIF AND ITS GEOLOGICAL IMPLICATIONS

China is abundant in Sb resources. The important Sb deposits in China are predominantly distributed at the southern margin of the Yangtze massif, which build up the largest Sb mineralization belt in the world. The ores from some deposits in the region show relatively significant variations in Pb isotopic composition. There exists obvious linear distribution for ores in the \{\}\ \{206\}Pb/\ \{204\}Pb\|\ \{207\}Pb/\ \{204\}Pb and \{\}\ \{206\}Pb/\ \{204\}Pb\|\{\{\}\ \{208\}Pb\}/\{\}\ \{204\}Pb diagrams. This linear distribution array is of no isochron significance and can be attributed to the mixing of low radiogenic lead and highly radiogenic Pb. Ore lead from the Sb deposits in this region should belong to the crust\|mantle mixed Pb. Sb mineralization should take place in an open system, and the deep\|seated materials seem to have been involved in Sb mineralization.