摘要
江西冷水坑银多金属矿床是一个斑岩型矿床,花岗斑岩的Rb-Sr同位素年龄为131.0±5.1Ma,初始锶同位素比值为0.71105±0.00275;火山岩的Rb-Sr同位素年龄为129.7±8.9Ma,初始锶同位素比值为0.70456±0.00374。从成矿早阶段到晚阶段,形成温度为300～250℃,lgf_(O_2)从-30.12下降到-40.78;lgf_(CO_2)从2.29下降到0.22;lgf_(S_2)从-9.94到-11.6;pH值为4.3～4.8。从成矿期Ⅱ_1至Ⅱ_3阶段,硫化物的δ^(34)S值在-14.7‰～+4.0‰之间。从成矿早阶段到晚阶段,δ^(18)O_(H_2O)值由+5.5‰～+10.3‰下降到-8.2‰～+6.1‰;δD_(H_2O)值由-93.5‰到-54.0‰～-91.1‰。
The Lenshuikeng Ag-Pb-Zn ore deposit is a porphyry-type deposit. The Rb-Sr isotope age of the graniteporphyry rocks is 131. 0±5. 1 Ma, and the initial ^(87)Sr/^(86)Sr value is 0. 71105 ± 0. 00275. The Rb-Sr isotope age of the volcanic rocks is 129. 7±8.9 Ma, and the initial ^(87)Sr/^(86)Sr value is 0. 71424 ± 0. 00569. The ore-forming temperatures are 300℃ for stages Ⅰ_1 to Ⅰ_2, and 250℃ to 270℃ for stages Ⅱ_1 to Ⅱ_3. Mineralogical data indicate that fluids of stages Ⅰ and Ⅱ had the following chemical compositions: lgfo_2 from —30. 12 to —40.78, lgf_(CO_2) from 2. 29 to 0. 22 , lgfs_2 from —9. 94 to —11.6, pH values from 4. 3 to 4. 8,δ^(34)S values of sulphide minerals during stages Ⅱ_1 and Ⅱ_3, are — 14. 7‰ to +4, 0‰. The δ^(18)O_(H_2O) values of both minerals and fluids are + 5.5‰ to +10. 3‰ for stage Ⅰ_1 and then finally drop from —8. 2‰ to +6.1‰ during stage Ⅱ_3. The δD_(H_2O) values are —93. 5%o during stage Ⅰ_1 and then from —54. 0‰ to —91.1‰ during stage Ⅱ_3.
出处
《地质论评》
CAS
CSCD
北大核心
2002年第S1期193-197,共5页
Geological Review
关键词
同位素
银多金属矿床
江西冷水坑
isotope
Ag-Pb-Zn ore deposits
Lenshuikeng
Jiangxi
