云南中甸红山铜-多金属矿床新生代热泉喷流沉积型矿床

红山铜-多金属矿床位于滇西中甸红山一带,主矿体是一个石榴子石型夕卡岩矿床。野外考察中发现了一个叠加在夕卡岩矿体之上的热泉喷流构造,它保存了具典型热泉喷流特征的喷口。喷口附近产出近水平层状的含铁硅质岩中硫化物的硫同位素δ³⁴S为3.73‰~5.57‰,平均值5.08‰;铅同位素²⁰⁶Pb/²⁰⁴Pb和²⁰⁷Pb/²⁰⁴Pb比值分别为18.670~18.808和15.614~15.784,其硫、铅同位素组成与滇西地区喜马拉雅期斑岩和斑岩矿床的硫、铅同位素组成相似,暗示红山矿区有新生代的岩浆活动和成矿作用。该区新生代热泉喷流成矿作用的发现既丰富了对滇西中甸地区成矿作用的认识,也对红山铜-多金属矿床的成因有了更全面的了解,为该区进一步扩展找矿远景提供了重要依据。

CENOZOIC HOT-SPRING EXHALATIVE MINERALIZATION IN HONGSHAN COPPER-POLYMETALLIC DEPOSIT IN ZHONGDIAN, NW YUNNAN

The Hongshan copper-polymetallic deposit is located in Zhongdian district, northwestern Yunnan province, China. The main body of the deposit was a garnet-rich skarn type deposit. We discovered a hot-spring exhalative formation which overprinted on the skarn type deposit. The hot-spring exhalative formation had a well preserved spout with typical hot spring exhalative characteristics. The sulfur isotope compositions of the sulfides from the quartz vein in the exhalative spout varied from 3.73‰ to 5.57‰,with an average value being 5.08‰. The ratios of ²⁰⁶Pb/²⁰⁴Pb varied from 18.670 to 18.808, ²⁰⁷Pb/²⁰⁴Pb from 15.614 to 15.784, respectively. The sulfur and lead isotopic compositions were similar to that of the Himalayan porphyries and porphyry-type deposits in western Yunnan, which comprehened the Cenozoic magmatic activity and mineralization occurring in Hongshan area. The discovery of hot-spring exhalative mineralization not only deepened the understandings of mineralization processes in Zhongdian area and metallogenesis of Hongshan copper-polymetallic deposit, but also supported an important inspiration for expanding the exploration prospect area in northwestern Yunnan.