滇西喜马拉雅期斑岩型矿床硫、铅同位素特征及地质意义

滇西地区的九顶山铜钼矿、北衙金矿和姚安铜矿是与喜马拉雅期斑岩有关的矿床.九顶山、北衙和姚安矿区的硫、铅同位素组成特征十分相似：各矿床的δ（34S）组成分布范围比较窄,在-2.4×10^-3～4.5×10^-3之间,平均值为0.64×10^-3,具有明显的塔式分布,说明硫主要为深部岩浆来源;各矿床的Pb同位素组成（N（206 Pb） /N（204 Pb）,N（207 Pb）/N（204 Pb）,N（208 Pb）/N（204 Pb））相似,都比较稳定,依据构造模式判别及成因分类综合分析,铅具有深源性,主要来源于地幔和下地壳,显示造山带铅的特征.研究结果表明,滇西地区与喜马拉雅期斑岩有关的矿床具有相同的成矿物资来源,主要成矿物质都来自深部地幔.

S, Pb isotopic characteristics of alkaline-rich porphyry deposits in Western Yunnan and the geological significance

Jiudingshan Cu-Mo deposit ,Beiya Au deposit and Yaoantong Cu deposit inwest Yunnan province are all related to the Himalayan porphyry. The paper describes their S, Pb isotopic characteristics. The S isotope composition is similar with tower distribution style and narrow value interval of 8（34 S） of -2.4×10^-3-4.5×10^-3 and average of 0.64×10^-3 characterized by deep magmatic source. The Pbisotope composition is stable and （N（^206 Pb）/N（^204 Pb）, N（^207 Pb）/N（^204 Pb）, N（^208 Pb）/N（^204 Pb）） similar characterized by deep source, mainly from mantle and the lower crust and orogenic belt according to geotectonic setting discrimination model and comprehensive analysis of genetic classification. The results indicate that the ore-forming materials of alkaline-rich porphyry deposits in western Yunnan are of the same source, mainly originated from mantle and lower crust.