青海省苦海汞矿床形成条件及成因探讨

Study on Forming Conditions and Metallogenesis of Kuhai Mercury Deposit,Qinghai Province

苦海汞矿床是位于东昆仑造山带南带东段上的大型含金汞矿床。围岩为一套滨海一浅海相富含碳质碳酸盐（石英砂岩）建造。矿体受地层和构造联合控制，一般产在褶皱的层间剥离裂隙、构造裂隙及节理中，或产于褶皱翼部的断裂破碎带内。矿床成矿流体以建造水和大气降水为主，并可能有岩浆热液的加入。成矿流体盐度（w（NaCl））为1．90％～5．70％，密度为0．78～0．97g／cm^3；流体包裹体均一温度为118．8～291．6℃；成矿压力约43．24MPa，成矿深度为4．56km。研究表明，该区下二叠统含碳地层提供了主要的成矿物质，晚三叠世受构造造山作用及相应的岩浆侵入所驱动的热液流体活化了矿质，并迁移至褶皱带层间剥离裂隙等部位沉淀成矿。总体上，该矿床为一受构造和地层联合控制的中偏低温热液矿床，相当于造山型金矿系列的浅成矿床。

Kuhai gold-bearing mercury deposit is located in the southern orogenic belt of Eastern Kunlun. Its wall rocks are a suit of shore to shallow sea facies carbonaceous carbonate and quartz sandstone formations. Ore bodies are jointly controlled by both strata and structures, and usually they are distributed in folded layers＇ fissures, structural fissures and joints or in the broken belts of fold flanks. Metallogenic fluids are mainly rock formation water and meteoric water as well as possible addition of magmatic hydrothermal solutions. The ore forming fluids contain NaCl of 1.90%-5.70% and the densi ty is in the range of 0.78 - 0.97 g/cm^3. The fluid inclusions show homogenized temperature at 118.8 - 291.6℃. The metallogenic pressure is about 43.24 MPa, correspondent to a depth of 4.56 km. Studies indicate that the Low Permian carbon bearing strata in the area has provided the main ore-forming materials which were further mobilized by magmatic hydrothermal fluids during the Late Triassic tectonic activities and finally formed as mineral deposit at the broken folded belts. Overall, Kuhai mercury deposit is a middle to low temperature hydrothermal mineral deposit and is considered as an epizonal deposit in terms of orogenic gold deposit series.