摘要
断裂构造控制的脉状Au-Ag-Pb-Zn矿床中,Au和Ag-Pb-Zn的富集存在多期流体叠加和同源流体演化等不同认识,围绕这一问题,本文聚焦中亚造山带南缘中段北山地区,选取带内同时富集Au和Ag-Pb-Zn的三个井矿床为典例开展解剖,探究脉状Au-Ag-Pb-Zn矿床的成矿作用特征和成因机制。研究发现,三个井矿床成矿流体属于变质来源的中-低温(375~304℃)、中-低盐度w(NaCl_(eqv))(1.7%~13.5%)H_(2)O-CO_(2)-NaCl体系。黄铁绢英岩阶段(S1)的流体沉淀以水岩反应为主,石英-菱铁矿-多金属硫化物阶段(S2)以沸腾作用为主。矿物溶解再沉淀作用贯穿整个S2阶段,使得成矿元素在矿物间发生不同程度的迁移,且该阶段早期(S2-1)以金矿化为主,晚期(S2-2)以银铅锌矿化为主。综合分析表明,三个井矿床中Au和Ag-Pb-Zn共生并非两种类型成矿流体的简单叠加,而是同一成矿流体在物理化学条件变化过程中相继沉淀的结果,这一认识对造山带中同类型矿床的成矿机制解析和成矿规律研究具有借鉴和参考意义。
The co-enrichment of Au with Ag-Pb-Zn in structurally controlled lode deposits is interpreted through differing models,including overprinting by multiple fluid events or evolution from a common fluid source.To address this,we focus on the Beishan region in the central segment of the southern Central Asian Orogenic Belt.The Sangejing deposit,a typical co-enriched Au-Ag-Pb-Zn system,is examined to elucidate the characteristics and genetic mechanisms of this mineralization style.Our results show that the ore-forming fluids at Sangejing represent a metamorphic-derived,moderate-to low-temperature(375-304℃),moderate-to low-salinity(1.7%-13.5%NaCl_(eqv))H_(2)O-CO_(2)-NaCl system.Mineral precipitation during the sericitic-pyritic alteration stage(S1)resulted primarily from water-rock interaction,whereas the quartz-siderite-polymetallic sulfide stage(S2)was driven mainly by fluid boiling.Mineral dissolution-reprecipitation was pervasive during S2,facilitating variable redistribution of ore-forming elements.The early substage(S2-1)featured Au mineralization,and the late substage(S2-2)was characterized by Ag-Pb-Zn mineralization.The findings demonstrate that the Au and Ag-Pb-Zn co-enrichment at Sangejing did not originate from the simple overprinting of two distinct fluids but from the sequential precipitation from a single evolving fluid system in response to physicochemical changes.
作者
刘启凡
张成
张青
高征西
保善斌
李奥冰
曹磊
付乐兵
LIU Qifan;ZHANG Cheng;ZHANG Qing;GAO Zhengxi;BAO Shanbin;LI Aobing;CAO Lei;FU Lebing(Sichuan Gold Group Co.LTD,Chengdu 610000,China;School of Earth Resources,China University of Geosciences,Wuhan 430074,China;Geological Survey and Research Institute of Inner Mongolia,Hohhot 010020,China;Inner Mongolia Key Laboratory of Magmatic Mineralization and Ore-Prospecting,Hohhot 010020,China;Qinghai Provincial Geological Survey Bureau,Xining 810000,China)
出处
《地学前缘》
北大核心
2026年第2期419-439,共21页
Earth Science Frontiers
基金
内蒙古自然资源厅勘查处综合预算项目“内蒙古北山成矿带金铜矿成矿关键问题研究及找矿预测”
内蒙古自治区岩浆活动成矿与找矿重点实验室项目“内蒙古阿巴嘎旗北部银铅锌多金属矿成矿背景、机制及找矿方向”
青海省有色地质矿产勘查局项目“青海省沟里-巴隆地区金矿成矿规律研究和沟里矿集区深部及外围找矿预测”。
关键词
中亚造山带
北山
三个井
金多金属矿床
金-银-铅-锌富集机制
矿物地球化学
Central Asian Orogenic Belt
Beishan area
Sangejing
gold-polymetallic deposits
gold-silver-lead-zinc enrichment mechanism
mineral geochemistry
