摘要
老挝琅勃拉邦—泰国黎府成矿带北段、中段和南段分别发育造山型、斑岩-夕卡岩型和浅成低温热液型金矿。桑通金矿是该成矿带中段近年来新发现的脉型金矿,其成因研究对进一步完善区域成矿理论、支撑找矿勘查具有重要意义。本研究在详细的矿相学、岩相学研究基础上,开展了流体包裹体显微测温和氢氧同位素分析。桑通金矿成矿流体主要来源于岩浆热液,初始成矿流体属中温、低盐度H_(2)O-NaCl体系,在成矿流体演化过程中,中低温、高盐度、富CO_(2)流体混入,并可能在成矿晚阶段混入大气降水,流体混合作用叠加水-岩反应导致大规模金沉淀。桑通金矿为低硫型浅成低温热液型金矿,主阶段成矿深度为1.1~1.8 km。桑通金矿地质特征与成矿带南段的大型浅成低温热液型切垂金矿类似,但具有更大的成矿深度,且受大气降水影响较小。综合认为,成矿带中段已知斑岩-夕卡岩型金矿周边发育区域张性断裂的中酸性火山岩区可能是浅成低温热液型金矿的找矿有利区,已发现的该类型金矿化点也具有一定的深部找矿潜力。
The Luang Prabang(Laos)-Loei(Thailand)metallogenic belt hosts orogenic-type deposits in its northern section,porphyry-skarn deposits in the middle,and epithermal gold deposits in the south.The recently discovered Sangthong vein-type gold deposit in the middle section of this belt provides key insights into regional metallogeny and has important implications for gold exploration.Based on detailed mineralogy and petrology,combined with fluid inclusion microthermometry and H-O isotope analysis,we determined the characteristics and evolution of the ore-forming fluids.Our results indicate a magmatic-dominant source for the fluids.The initial ore-forming fluid belongs to a medium-temperature,low-salinity H_(2)O-NaCl system.During its evolution,this fluid mixed with a medium-low temperature,high-salinity,CO_(2)-rich fluid,with significant meteoric water input occurring in the late hydrothermal stage.The Sangthong deposit is classified as a low-sulfidation epithermal gold deposit,formed at depths of 1.1-1.8 km.While it shares geological characteristics with the large-scale Chatree epithermal deposit in the southern part of the belt,Sangthong exhibits a relatively deeper mineralization depth and less meteoric water involvement in its fluid system.We therefore propose that the intermediate-acidic volcanic rock areas adjacent to extensional faults in the middle section of the Luang Prabang-Loei metallogenic belt are highly prospective for new epithermal gold discoveries.Furthermore,the epithermal gold occurrences in the middle section of the belt show significant potential for gold discovery at greater depths.
作者
郭林楠
杨永飞
廖震文
张彬
徐思维
梁慧敏
张炳林
张向飞
曾祥婷
GUO Linnan;YANG Yongfei;LIAO Zhenwen;ZHANG Bin;XU Siwei;LIANG Huimin;ZHANG Binglin;ZHANG Xiangfei;ZENG Xiangting(Chengdu Center of China Geological Survey(Geosciences Innovation Center of Southwest China),Chengdu 610081,China;Shaanxi Mineral Resources and Geological Survey,Xi’an 710068,China)
出处
《地学前缘》
北大核心
2026年第2期399-418,共20页
Earth Science Frontiers
基金
国家自然科学基金项目(42472142,42102113)
国家重点研发计划项目(2021YFC2901803)
中国地质调查局地质调查项目(DD20230127,DD20230579)
陕西省自然科学基础研究计划一般项目(青年项目)(2022JQ-276)
国家留学基金管理委员会项目(202108575008)。
关键词
流体包裹体
氢氧同位素
低硫型浅成低温热液型金矿
桑通金矿
琅勃拉邦—黎府成矿带中段
fluid inclusion
H-O isotopes
low sulfidation epithermal gold deposit
Sangthong gold deposit
middle section of the Luang Prabang-Loei metallogenic belt
