投稿时间：2025-06-09
修订日期：2026-03-01
网络发布日期：2026-04-22
中文摘要:长沙-平江大断裂（长平断裂）是一条呈北东向的深大断裂，断裂北段是湖南省重要的热液型钴多金属成矿区，但在断裂南段尚未有热液型钴成矿作用的报道。文章首次在该断裂南段的盐田桥矿床识别出了钴的成矿作用，进一步揭示了钴的成矿时代、赋存状态和富集规律。在详细的野外地质调查基础上，利用TIMA扫面、EPMA扫面和定量分析、独居石U-Pb定年，并结合黄铁矿的原位S同位素分析，揭示盐田桥矿区的成矿过程可划分为4个成矿阶段：角砾岩-硫化物阶段（Ⅰ）、石英脉-磁铁矿阶段（Ⅱ）、石英脉-黄铜矿阶段（Ⅲ）和重晶石脉-黄铁矿阶段（Ⅳ）。在第Ⅳ阶段识别出3种不同类型的黄铁矿（Py4a、Py4b和Py4c），其中，Py4c是整个矿区的主要载钴矿物；获得与Py4c共生独居石的U-Pb定年结果为（149.0±0.8）Ma；富钴黄铁矿（Py4c）中的Co、Ni与As含量呈明显的正相关，而与Fe、S含量呈负相关关系；盐田桥矿床各阶段黄铁矿的δ34S值多介于-13.5‰～-7.8‰。笔者综合研究认为，盐田桥矿床的成矿物源主要为冷家溪群，钴的成矿作用发生在晚侏罗世；载钴矿物（Py4c）为Py4b交代Py4a发生矿物的溶解和再沉淀所形成，Co、Ni主要以类质同象替代Fe的方式进入黄铁矿晶格；盐田桥矿床的钴成矿作用具有与长平断裂北段钴多金属矿床在形成时代、成矿阶段和矿物组合等方面的明显区别；长平断裂具有较好的钴金属找矿前景，衡阳盆地周缘的钴成矿作用也需引起重视。
Abstract:The Changsha-Pingjiang fault(Changping fault) is a major NE-trending deep-seated fault, its northern segment constitutes an important hydrothermal Co-polymetallic metallogenic belt in Hunan Province, however, hydrothermal Co mineralization has not been previously reported in its southern segment. This paper reports, for the first time, the identification of cobalt mineralization in the Yantianqiao deposit located within the southern segment of this fault. To further elucidate the metallogenic age, occurrence state, and enrichment mechanisms of cobalt, detailed field geological investigations were carried out and combined with mineral TIMA mapping, EPMA mapping and quantitative analysis, monazite U-Pb dating, and in-situ sulfur isotope analysis of pyrite. The results reveal that the mineralization process at Yantianqiao can be divided into four stages: breccia-sulfide stage( Ⅰ),quartz vein-magnetite stage(Ⅱ), quartz vein-chalcopyrite stage(Ⅲ), and barite vein-pyrite stage(Ⅳ). Three distinct types of pyrite(Py4a, Py4b and Py4c) were identified in stage Ⅳ, with Py4c being the primary cobalt-bearing mineral throughout the deposit. Monazite coexisting with Py4c yielded a U-Pb age of(149.0±0.8)Ma(MSWD=1.8). Cobalt-rich pyrite(Py4c) exhibits a significant positive correlation between Co, Ni and As contents, and a negative correlation between Co, Ni and Fe, S contents. The δ34S values of pyrite from various stages in the deposit predominantly range from-13.5‰ to-7.8‰. The comprehensive analysis indicates that: the primary oreforming material at Yantianqiao was derived mainly from the Neoproterozoic Lengjiaxi Group, with Co mineralization occurring during the Late Jurassic; the cobalt-bearing mineral(Py4c) formed via dissolution and reprecipitation during the replacement of Py4a by Py4b, and Co and Ni primarily entered the pyrite lattice through isomorphic substitution for Fe; the Co mineralization at Yantianqiao exhibits distinct differences from Co-polymetallic deposits in the northern segment of the Changping Fault in terms of formation age, mineralization stages, and mineral assemblages. The Changping Fault shows promising potential for Co exploration, and cobalt mineralization around the Hengyang Basin also warrants attention.
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基金项目:地球深部探测与矿产资源勘查深地国家科技重大专项(编号:2025ZD1007803、2025ZD1007801);湖南省自然科学基金(编号:2026JJ80746、2025JJ80404);湖南省地质院科研项目(编号:HNGSTP202306)联合资助
引用文本：
盛丹,李彬,陈剑锋,黄建中,董国军,柏道远,曾广乾,王灵珏.2026.湖南省长平断裂南段盐田桥矿床钴的赋存状态、形成时代及地质意义[J].矿床地质,45(2):229~250SHENG Dan,LI Bin,CHEN JianFeng,HUANG JianZhong,DONG GuoJun,BAI DaoYuan,ZENG GuangQian,WANG LingJue.2026.Occurrence state and mineralization age of cobalt within Yantianqiao deposit located in southern segment of Changsha-Pingjiang fault, Hunan Province,and its geological implication[J].Mineral Deposits45(2):229~250
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