宁夏海原西华山地区金矿床地质地球化学特征及成因分析  

Geological and Geochemistry Characteristics and Genesis Analysis of Gold Deposits in Xihuashan Area,Haiyuan,Ningxia

作　　者：苏力 朱海军 谷守江 杨兴科[2] 赵翌辰 孙雪平 何虎军[2] 韩珂[2] 张玉瑜 谭江 谢愿龙 张龙 高立博 SU Li;ZHU Haijun;GU Shoujiang;YANG Xingke;ZHAO Yichen;SUN Xueping;HE Hujun;HAN Ke;ZHANG Yuyu;TAN Jiang;XIE Yuanlong;ZHANG Long;GAO Libo(Geological Archive of Ningxia Hui Autonomous Region,Yinchuan 750021,Ningxia,China;School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,Shaanxi,China)

机构地区：[1]宁夏回族自治区地质资料馆,宁夏银川750021 [2]长安大学地球科学与资源学院,陕西西安710054

出　　处：《黄金科学技术》2024年第2期191-206,共16页Gold Science and Technology

基　　金：宁夏回族自治区科技厅自然科学基金项目“宁夏海原县西华山铜金矿成矿时代及物质来源研究”(编号:2021AAC03478);中国地质调查局北山-祁连成矿带地质矿产调查项目“宁夏中卫市南西华山铜金矿调查”(编号:1212011085088、资[2010]矿评01-04-15、资[2011]矿评02-04-22、资[2012]矿评02-002-021)联合资助

摘　　要：宁夏海原西华山金矿区位于秦岭—祁连—昆仑造山带之祁连构造成矿带,在该矿区已发现马场和柳沟2个金矿床。区内含矿地层为长城系海原群变质地层,矿脉受断裂带控制,矿石类型主要为蚀变煌斑岩型、石英脉型和蚀变岩型。为了查明西华山金矿区矿床成因类型和成矿过程,对马场和柳沟2个金矿床开展了野外地质调查、流体包裹体显微测温和H-O-S同位素地球化学研究工作。研究表明:马场和柳沟金矿床石英流体包裹体均一温度范围分别为140.1~382.6℃和203.2~353.9℃,集中在250~260℃和270~280℃;盐度[w(NaCleq)]分别为2.57%~10.72%和5.28%~12.08%,集中在6%~7%和7%~8%;成矿期成矿流体δD值分别为-86.5‰~-87.2‰和-90.2‰~-91.6‰,δ^(18)O值分别为7.4‰~8.7‰和8.7‰~10.0‰;2个矿区矿石黄铁矿中δ^(34)S分布范围为-1.00‰~0.27‰。综合研究认为,区内金矿成矿流体属于中低温、中低盐度的流体,主要来源于岩浆水;硫也主要源于岩浆,有少量可能源于围岩地层;区内金矿床属于与晚古生代中酸性岩浆活动有关的中低温低盐度岩浆热液型金矿。The Xihuashan gold mining area is located in the Qilian tectonic metallogenic belt of the Qinling-Qilian-Kunlun orogenic belt,Machang and Liugou gold deposits have been found in the mining area.The orebearing strata in the area are the metamorphic strata of the Haiyuan group,and the veins are controlled by the fault zone.The ore types are mainly altered lamprophyre type,quartz vein type and altered rock type.In order to find out the genetic type and metallogenic process of the Xihuashan gold deposit,the field geological survey,microthermometry of fluid inclusionsand H-O-S isotope geochemistry of Machang and Liugou gold deposit were carried out.The results show that the homogenization temperature of quartz fluid inclusions in Machang gold deposit ranges from 140.1℃to 382.6℃,and mainly concentrated in 250~260℃,the corresponding salinity is 2.57%~10.72%NaCleq.The homogenization temperature of quartz fluid inclusions in Liugou gold deposit ranges from 203.2℃to 353.9℃,and mainly concentrated in 270~280℃,and the freezing point temperature is-8.2~-3.2℃,the corresponding salinity is 5.28%~12.08%NaCleq,mainly concentrated in 7%~8%NaCleq.TheδD values of quartz in Machang gold deposit are-86.5‰~-87.2‰,and theδ^(18)O values are 15.4‰~16.7‰.TheδD values of quartz in Liugou gold deposit are-90.2‰~-91.6‰,theδ^(18)O values are 15.7‰~17.0‰.Therefore,the ore-forming fluid belongs to the medium-low temperature medium-low salinity fluid,the main source of magmatic water.Additionally,theδ^(34)S values in the pyrite of the Machang and Liugou mine areas range from-1.00‰to 0.27‰.The combination of the S isotopic composition in the regional stratigraphy and electron probe analysis of pyrite suggests that the sulfur source of gold-bearing sulfides(withδ^(34)S values close to zero)is primarily derived from deep magma,whilesulfides containing trace amount of gold or without gold are derived from the surrounding rock stratigraphy.During the Late Garidonian period,the magmatic dynamic and thermal influe

关 键 词：流体包裹体 H-O-S同位素 成矿流体 矿床成因 祁连构造带 西华山金矿区 

分 类 号：P618.51[天文地球—矿床学]