摘要
三官庙金矿床位于秦岭造山带南秦岭北部逆冲推覆构造带内,为断裂构造控矿的热液型矿床。热液成矿期划分为成矿早阶段(S1)、主阶段(S2)和晚阶段(S3)。成矿主阶段流体包裹体的完全均一温度T_(h)为150~420℃,盐度为2.1%~24.1%;成矿晚阶段T_(h)为81~190℃,盐度为5.6%~22.2%。包裹体研究显示,在成矿主阶段温度>250℃时,以流体混合作用为主而导致矿物沉淀;在成矿主阶段温度<250℃及成矿晚阶段,以流体沸腾作用为主而导致矿物沉淀。成矿主阶段成矿流体的δD_(V-SMOW)为-84.4‰~-77.0‰,δ^(18)O_(H_(2)O)为5.0‰~5.7‰,成矿流体来源以岩浆水为主,同时混入了外来流体。成矿流体的δ^(13)C_(ΣC)为-13.5‰~-5.2‰,反映碳为岩浆来源并受到低温蚀变的影响。黄铁矿单矿物δ^(34)S_(CDT)为-2.73‰~-1.31‰;毒砂单矿物δ^(34)S_(CDT)为-3.36‰~0.03‰,反映成矿物质硫为典型的单一岩浆来源。综上分析,认为三官庙金矿床为岩浆热液成因,其成矿机制为:印支期末,在钠长(角砾)岩形成过程中,含金热液流体沿断裂构造运移,在距离钠长(角砾)岩较远地段的层间破碎带内,成矿流体发生混合及沸腾作用,促使成矿物质发生沉淀,最终形成三官庙金矿床。
The Sanguanmiao gold deposit is located in the thrust⁃nappe belt in the northern South Qinling Oro⁃gen.It is a fault⁃controlled magmatic⁃hydrothermal deposit.Gold mineralization at Sanguanmiao can be divided into pre⁃ore(S1),main⁃ore(S2)and post⁃ore(S3)stages.Massive sulfide and calcite⁃quartz veins with gold mineralization were formed in S2.The homogenization temperatures(T_(h))of S2 fluid inclusions are of 150-420℃,with salinities of 2.07%-24.15%NaCl,whereas the S3 ores are of 81-190℃and 8.55%-22.17%NaCl.Fluid inclusion petrologic and microthermometric analyses show that the gold precipitation was resulted from fluid mixing and subsequent fluid boiling during the main ore stage.TheδD_(V-SMOW)values of the S2 ore⁃forming fluid range from-84.4‰to-77.0‰,and theδ^(18)O_(H_(2)O)values range from 5.0‰to 5.7‰,indicating the mixing of magmatic water and meteoric fluids.The ore⁃fluidδ^(13)C_(ΣC)values range from-13.5‰to-5.2‰,indicating a magmatic carbon origin influenced by low⁃temperature alteration.Theδ^(34)S_(CDT)values range from-2.73‰to-1.31‰for pyrite,and from-3.36‰to 0.03‰for arsenopyrite,suggesting a single magmatic sulfur source.Thus,we considered that the Sanguanmiao gold deposit is associated with magmatic⁃hydrothermal activity,and proposed a metallogenic model as follows:the gold⁃bearing hydrothermal fluids migrated along fault structures during the late Indosinian Orogeny.Fluid mixing and boiling then occurred in the interlayer fracture zone,which caused gold precipitation and eventually the Sanguanmiao gold mineralization.
作者
汪超
王瑞廷
刘云华
薛玉山
胡西顺
牛亮
WANG Chao;WANG Ruiting;LIU Yunhua;XUE Yushan;HU Xishun;NIU Liang(School of Earth Science and Resources,Chang'an University,Xi'an,Shaanxi710054,China;Xi'an Northwest Geology Research Institute of Nonferrous Metals Co.,Ltd.,Xi'an,Shaanxi710054,China;Shaanxi Engineering Technology Research Center of Comprehensive Utilization of Mineral Resources,Xi'an,Shaanxi710054,China;Northwest Nonferrous Geological and Mining Group Co.,Ltd.,Xi'an,Shaanxi710054,China)
出处
《现代地质》
CAS
CSCD
北大核心
2021年第6期1551-1564,共14页
Geoscience
基金
中国地质调查局项目“矿集区矿产调查和深部找矿预测”(DD2019057018)
陕西省地勘基金项目(61201707317)
国家自然科学基金面上项目(41872219)。
