摘要
北祁连山西段金矿床以剪切带型为主 ,控矿的主导因素是剪切构造和成矿流体。对寒山、鹰嘴山和珠龙等代表性矿床的流体包裹体的研究表明 ,产于剪切带中金矿床的成矿流体具有中低温、低密度和低盐度等特点 ,包裹体中气体和液体 CO2 / H2 O比值较高。稳定同位素研究结果表明 ,不同矿床的成矿流体来源不尽相同 ,鹰嘴山矿床和寒山矿床成矿流体来源以深部流体为主 。
In the past several years,more than a dozen of gold deposits and gold occurrences,such as Hanshan,Yingzuishan,Changma,Hongkouzi and Zhulong,have been discovered in the western part of North Qilian Mountain.All the deposits are of shear zone type and are developed along a group of WNW\|striking shear zones.Microthermometric measurements were made on quartz\| and calcite\|hosted inclusions.All of the fluid inclusions in two phases (vapor+liquid with V/L ratios of 5%～10%) and minor amounts of liquid phase hosted in both quartz and calcite are very small,ranging from 1 to 15 μm.Their homogenization and salinity are 170～310 ℃ and 5\^4%～10\^5% NaCl for Hanshan,175～355 ℃ and 3\^8%～9\^3% NaCl for Yingzuishan,115～155 ℃ and 1 4%～7 7% NaCl for Zhulong,and 85～215 ℃ and 4\^0%～9\^4% NaCl for Changma.In general,the hydrothermal fluids,which are genetically responsible for the gold deposits in the western part of the Qilian Mountain,are characterized by low to middle temperatures and low salinity.A few measurements for the composition of the single fluid inclusions indicate that both liquid and vapor are of high CO\-2/H\-2O ratio.\;Sulfur isotope data of the Hanshan gold deposit range from -1\^9‰ to 1\^7‰ with high peak at 0‰～0 5‰ in histogram.Oxygen isotope data of the hydrothermal fluids ( δ 18 O H\-2O ) change greatly in different deposits or gold occurrences.They are 7\^7‰～4\^7‰,7\^4‰～3\^6‰,2\^0‰ and -3\^8‰～3\^4‰ in Hanshan,Yingzuishan,Hongkouzi and Zhulong,respectively,which perhaps suggest that the magmatic fluids or the mantle fluids mixed increasingly with meteoric water from Hanshan,Yinzuishan,Hongkouzi to Zhulong during mineralization.In view of the absence of magmatic activities during the gold mineralization together with the sulfur isotopic evidence and strong enrichment of CO\-2,it is concluded that the hydrothermal fluids responsible for the gold mineralization in the western part of the Qilian Mountain are possibly derived from the mantle along the deep faults.
出处
《矿床地质》
CAS
CSCD
北大核心
2000年第1期9-16,共8页
Mineral Deposits
基金
国家杰出青年基金!(编号 :4 982 51 0 3 )
国家计委科技找矿项目!(编号 :JG94 71 90 2 )
关键词
金矿床
成矿流体
成矿机制
北祁连山
剪切带
gold deposit,shear zone type,fluid inclusion,North Qilian Mountain
