黔西南低温成矿区萤石矿床成矿规律:与金锑矿床的空间关系

The metallogenic regularity of fluorite deposits in the low temperature metallogenic area of Southwest Guizhou:their spatial relationship with gold and antimony deposits

黔西南低温成矿区位于右江盆地北缘,发育众多中-大型金、锑矿床,是华南大面积低温成矿域的重要组成部分。除热液金、锑矿床外,该区普遍发育萤石矿化。本文在分析总结前人大量研究工作的基础上,结合最新勘查成果,对黔西南低温成矿区萤石矿床的成矿规律,以及萤石矿床与低温矿床之间的空间联系进行总结分析。结果表明,该区萤石形成与金-锑矿化为代表的大面积低温热液成矿事件有关。萤石微量元素、Sr同位素和包裹体H-O同位素组成揭示成矿流体为深部循环富放射性成因Sr流体与地层水混合,其冷却过程是萤石沉淀的主要机制。最新的勘探成果表明,区域上深大断裂控制了萤石矿床的空间展布,而矿床中萤石的产出明显受不同岩性面(或不整合面)之间的滑脱构造控制,多层次滑脱构造形成的背斜(穹隆)是萤石成矿的有利部位。由此认为,右江盆地北缘水城-紫云断裂与师宗-弥勒断裂的交汇部位(六枝-普安-晴隆一带)是萤石成矿远景区,热液金、锑矿床控矿背斜外围和多层次构造滑脱面具有较大的萤石成矿潜力。

The low-temperature metallogenic area of Southwest Guizhou,located in the northern margin of the Youjiang basin,have many media to large-scale gold and antimony deposits.It is an important part of the large-scale low-temperature metallogenic domain in South China.In addition to hydrothermal gold and antimony deposits,fluorite deposits are also widely developed in this area.Based on the analysis and summary of a large number of previous research data,combined with recent geological exploration achievements,in this paper,we have summarized and analyzed the metallogenic regularity of fluorite deposits and the spatial relationship between them and other low-temperature deposits in the low-temperature metallogenic area of Southwest Guizhou.The results show that the formation of fluorite in this area is related to the large-scale low-temperature hydrothermal mineralization represented by the Au-Sb mineralization.The compositions of trace elements and Sr isotopes of fluorites and H-O isotopes of inclusion fluids in fluorites reveal that the ore-forming fluid was a mixture of the deep circulating radioactive Sr-enriched fluid and the stratigraphic formation water,and its cooling process had mainly resulted in the fluorite precipitation.Recent exploration results show that the spatial distribution of fluorite deposits are controlled by regional deep and large faults,while the occurrence of fluorite in the deposits is obviously controlled by the detachment structure between different lithological planes(or unconformity planes).Especially,the anticline(dome)formed by multi-level detachment structures is a favorable position for the fluorite mineralization.Therefore,it is believed that the intersection region of the Shuicheng-Ziyun fault and the Shizong-Mile fault(the Liuzhi-Pu'an-Qinglong area)in the north margin of Youjiang Basin is a good prospect area of fluorite mineralization.In particular,there is good exploration potential of fluorite resource in peripheries of the anticlines and multi-level structural detachment surfaces which are controlling structures of hydrothermal gold and antimony deposits.