湘南坪宝矿田岩浆热液成矿系统深部探测与地球化学约束

Deep Exploration and Geochemical Constraints of the Magmatic Hydrothermal Mineralization System in the Pingbao Ore Field,Southern Hunan Province

湘南是我国乃至世界最重要的钨锡多金属矿集区之一,发育了坪宝、柿竹园、骑田岭等多个大型矿床(田)。随着浅部资源逐渐枯竭,成矿系统深延与探测成为找矿突破的重点,尤其是覆盖层下隐伏成矿岩体、流体运移通道与矿体赋存空间的准确识别。本文以湘南坪宝矿田为例,采用广域电磁、构造解析与地球化学等方法揭示了成矿系统的空间结构与物质组成:(1)矿田深部(<5 km)存在4个隐伏的燕山期花岗岩体,包括宝山、黄沙坪、大坊、野鹅塘,岩体呈现不规则形态;(2)岩体侵位受NNE走向、NE走向与NW走向的区域断裂交汇联合控制,其岩体接触带与次级断裂为主要的控矿构造;(3)断层破碎带中方解石、石英、赤铁矿等热液矿物为成矿流体活动留下的痕迹,可用来识别成矿流体的源区与路径;(4)科学钻探证实了矿体与成矿运移通道深延稳定,且可能与深部隐伏岩体导通;(5)宝山矿区西部、黄沙坪矿区东部、大坊与野鹅塘矿区深部应为该区未来找矿勘查的重点。通过广域电磁、构造解析与矿物地球化学分析可以深入认识隐伏岩体的空间形态与形成时代,构建成矿物质与流体的“源-运-储”模型,开展成矿系统的深部探测与成矿潜力评价。

The Xiangnan region,situated in the southern part of Hunan Province,China,stands as one of the most significant polymetallic mineral districts nationally and globally.Hosting prominent deposits like Pingbao,Shizhuyuan,and Qitianling,the region has played a pivotal role in mineral resource exploration and development.As the shallower mineral resources gradually deplete,the focus of breakthroughs in prospecting has shifted towards the extension of mineralization systems and precise detection methods.This is especially crucial for identifying concealed ore-forming rock bodies,fluid migration pathways,and the spaces where ore bodies are located beneath the overlying geological layers.Taking the Pingbao ore field in southern Hunan Provinces as a case study,this paper utilizes various methods,including wide-area electromagnetic surveys,structural analysis,and geochemistry,to unveil the spatial structure and material composition of the mineralization system.In the deep part of the ore field(<5 km),four concealed Jurassic granite bodies were identified,namely,Baoshan,Huangshaping,Dafang,and Yeyetang.These bodies exhibit irregular shapes.The emplacement of these bodies was jointly controlled by intersecting regional faults trending NNE,NE,and NW,with contact zones and secondary faults being the primary ore-controlling structures.Within fault-fracture zones,minerals such as calcite,quartz,and hematite serve as traces of hydrothermal mineralization activities,enabling the identification of the source areas and pathways of ore-forming fluids.Scientific drilling confirms the stable deep extension of ore bodies and ore migration pathways,possibly connecting with concealed deep-seated rock bodies.Prioritization for future exploration in this region should focus on the western part of Baoshan,the eastern part of Huangshaping,and the deep parts of Dafang and Yeetang.Through wide�area electromagnetic surveys,structural analysis,and mineral geochemical analysis,a comprehensive understanding of the spatial morphology and formation age of concealed rock bodies can be achieved.This facilitates the construction of a'source-migration-storage'model for ore-forming minerals and fluids,enabling a deeper exploration of the mineralization system and a thorough assessment of ore-forming prospects.