雪峰弧形构造带中段典型金锑矿床成矿流体对比研究  

A comparative study of the ore-forming fluids of the typical gold-antimony deposits along Middle Xuefeng arc structure belt

作　　者：周超 孙骥 郭爱民 贾朋远 陆文 隗含涛 郭鼎 蔡毅 ZHOU Chao;SUN Ji;GUO Aimin;JIA Pengyuan;LUWen;WEI Hantao;GUO Ding;CAI Yi(Hunan Institute of Geology Survey,Changsha 410116,Hunan,China;Key Laboratory of Mineralization and Resource Evaluation,Ministry of Natural Resources,Beijing 100037,China;Henan Polytechnic Institute,Nanyang 473000,Henan,China)

机构地区：[1]湖南省地质调查院,湖南长沙410116 [2]自然资源部成矿作用与资源评价重点实验室,北京100037 [3]河南工业职业技术学院,河南南阳473000

出　　处：《中国地质》2020年第4期1241-1259,共19页Geology in China

基　　金：湖南省自然资源厅科研项目(2017-03,2019-02);湖南省地质院科研项目(201701,2017-01-01,201902-01,201912);湖南省重点领域研发计划项目(2019SK2261);国家重点研发计划(2017YFC0601506)联合资助。

摘　　要：古台山矿床和龙王江矿床是雪峰弧形构造带中段颇具代表性的石英脉型金锑矿床。古台山金锑矿床位于白马山复式岩体的外接触带,而龙王江金锑矿床则距离白马山岩体较远。本文从流体包裹体和氢氧同位素研究入手,讨论了成矿流体的特征、来源及其与成矿的关系。流体包裹体岩相学观察和显微测温表明,古台山矿床成矿期石英中包裹体以气液水两相包裹体和CO2-H2O三相包裹体为主,均一温度集中在199~298℃,盐度集中在2.07%~11.46%NaCleqv;龙王江矿床成矿期石英中包裹体以气液水两相包裹体为主,均一温度集中在164~238℃,盐度集中在1.40%~8.41%NaCleqv。氢氧同位素研究表明,古台山矿床成矿流体来源主要为岩浆水和变质水的混合流体;龙王江矿床成矿流体主要来源于变质水。根据流体包裹体岩相学观察,结合显微测温,认为流体不混溶是导致古台山矿区矿质沉淀的主要机制;而龙王江矿区矿质沉淀很可能是温度和(或)压力的变化,或大气降水的加入(混合)所导致。The Gutaishan and Longwangjiang quartz vein type gold-antimony deposits, located in Xinhua and Xupu County,respectively, are two representative ones in the middle of Xuefeng arc structure belt. The Gutaishan gold-antimony deposit occurs in the external contact zone of Baimashan composite granite mass, while Longwangjiang gold-antimony deposit is far from Baimashan composite granite mass. Based on the study of fluid inclusions and hydrogen and oxygen isotopic geochemistry,this paper discusses the characteristics and origin of ore-forming fluids so as to provide an insight into the ore genesis. Petrographic observation and microthemometric measurements of fluid inclusions show that ore-forming stage quartz veins in the Gutaishan gold-antimony deposit mainly contain liquid-vapor two-phase aqueous inclusions and CO2-H2O three-phase inclusions. The homogeneous temperature and salinity of primary fluid inclusions are in the range of 199~298℃ and 2.07~11.46%NaCleqv. The oreforming stage quartz veins of the Longwangjiang gold-antimony deposit mainly contain liquid-vapor two-phase aqueous inclusions, with the homogeneous temperature from 164℃ to 238℃ and salinity from 1.40% NaCleqvto 8.41% NaCleqv. Hydrogen and oxygen isotopic geochemistry shows that the ore-forming fluids of the Gutaishan gold-antimony deposit was composed of the mixture of magmatic water and metamorphic water, and the Longwangjiang gold-antimony deposit was mainly derived from metamorphic water. Based on geological and fluid inclusion characteristics,it is suggested that fluid immiscibility may have been the main mechanism for metal precipitation in the Gutaishan gold-antimony deposit. The mechanism of the ore-forming process in the Longwangjiang deposit was probably caused by the change of temperature and/or pressure, or the addition(mixing) of metamorphic water.

关 键 词：流体包裹体 流体不混溶 古台山金锑矿床 龙王江金锑矿床 雪峰弧形构造带 矿产勘查工程 

分 类 号：P618.51[天文地球—矿床学] P618.66[天文地球—地质学]