摘要
湘东北黄金洞金矿田累计探明金资源量约为80 t,平均金品位为5×10^(-6),矿体主要赋存于NWW-近EW向倒转褶皱翼部的层间剪切断裂中。长期以来,由于缺乏对矿田构造格架和变形样式的系统解析,制约了对成矿规律的深入认识和找矿勘查的科学部署。通过对黄金洞金矿田进行精细的路线填图和野外构造解析,厘清了矿田褶皱构造格架和变形样式,并探讨了其形成机制及其对金矿勘查的启示意义。研究表明,黄金洞金矿田构造格架主要由NWW-近EW向褶皱和NE向断裂系统组成。NE向泥湾断裂西盘主要发育枢纽呈NWW走向、轴面倾向NNE的倒转背斜和向斜组合,东盘则主要发育枢纽近EW走向、轴面倾向N的褶皱组合。褶皱系统的初始变形受控于小木坪组与黄浒洞组之间的顺层滑脱断裂,是在区域NNE-SSW向挤压构造体制下,在滑脱断裂末端形成的断层传播褶皱。研究揭示,泥湾断裂下盘构造线相对上盘的逆时针偏转,可能受控于加里东期形成的近EW向隐伏逆断裂向北的逆冲推覆作用。综合分析认为:今后找矿工作应聚焦于褶皱翼部层间剪切断裂构成的容矿空间,重视矿体在垂向上的分段富集特征,修正泥湾断裂两盘缺位找矿思路,并加强NE向断裂与NWW-近EW向层间剪切断裂交会部位的勘查工作。本次精细构造格架的厘定为黄金洞金矿田及类似构造控矿区域的未来勘探提供了依据和借鉴。
The Huangjindong gold field,situated in the northeastern region of Hunan Province within the Jiangnan Orogen,represents a major gold production site,boasting cumulative proven resources of approximately 80 tonnes with an average grade of 5 g/t.The ore bodies are predominantly hosted within interlayer shear fractures that have developed along the limbs of overturned folds trending from northwest-west to east-west.Despite its economic significance,a comprehensive understanding of the ore-controlling structural architecture has been lacking.Historically,the absence of a systematic analysis of the structural framework and deformation styles has impeded both a profound understanding of metallogenic regularity and the scientific planning of exploration initiatives in this field.To address this deficiency,this study conducts a detailed structural analysis grounded in extensive,fine-scale route mapping and field-based structural observations.The primary objectives were to(1)delineate the fold architecture and characterize the deformation patterns that govern mineralization,(2)elucidate the formation mechanisms of the predominant structures,and(3)explore the implications for future gold exploration endeavors.Our findings reveal a structural framework characterized by two primary elements:a system of NWW-to E-W-oriented folds and a series of NE-oriented faults.A notable structural divergence is evident across the regional Niwan Fault.To the west of this fault,the fold system consists of overturned anticline-syncline pairs with NWW-trending hinges and axial planes consistently dipping towards the NNE.Conversely,the eastern block exhibits folds with E-W-oriented hinges and north-dipping axial planes,suggesting a significant counterclockwise deflection of structural trends in the footwall compared to the hanging wall.We propose that the initial development of this fold system was governed by a critical layerparallel décollement horizon located between the Xiaomuping and Huanghudong formations.Under a regional NNE-SSW compressional tectonic regime,this décollement facilitated detachment and slip,resulting in the formation of fault-propagation folds at its leading edge.We hypothesize that the observed deflection across the Niwan Fault was induced by subsequent northward thrusting along a concealed,approximately E-W-striking reverse fault.The fault in question likely originates from the Caledonian orogeny,and its movement has resulted in the differential rotation of the footwall block.The structural model developed in this study has significant implications for exploration.Future research should focus on:(1)systematically investigating the ore-hosting potential of interlayer shear fractures that have developed along the limbs of the identified folds,as these serve as primary fluid conduits and sites of mineral deposition;(2)considering the vertical segmentation and enrichment characteristics of ore shoots within these structures;(3)revising traditional exploration strategies that assumed a straightforward correlation of ore veins across the Niwan Fault;and(4)improving the targeting of intersections between the northeast-trending fault system and the northwest-west to east-west interlayer shear fractures,as these junctions likely functioned as high-permeability zones conducive to fluid concentration and enhanced gold deposition.This refined structural framework offers a robust foundation for future evidencebased exploration in the Huangjindong gold field and similar structurally controlled regions.
作者
高银梅
曾广乾
穆家乐
柏道远
刘中楠
王勇
GAO Yinmei;ZENG Guangqian;MU Jiale;BAI Daoyuan;LIU Zhongnan;WANG Yong(Henan Geology Mineral College,Zhengzhou 451464,Henan,China;Geological Survey Institute of Hunan Province,Changsha 410114,Hunan,China;Hunan Huangjindong Mining Co.,Ltd.,Yueyang 414500,Hunan,China;Geophysical and Geochemical Survey Institute of Hunan Province,Changsha 410114,Hunan,China)
出处
《黄金科学技术》
北大核心
2026年第1期74-90,共17页
Gold Science and Technology
基金
湖南省自然科学基金项目“多期次多级序构造对金成矿的控制——以湘东北黄金洞金矿为例”(编号:2024JJ8366)
自然资源部新一轮找矿突破战略行动科技支撑项目“雪峰金锑矿构造解析与找矿预测”(编号:ZKKJ202408)
湖南省地质院科技计划项目“湘南坪宝矿田构造控岩控矿作用及深边部找矿方向研究”(编号:HNGSTP202507)
“江南古陆金成矿带黄金洞矿区深部三维智能预测技术及勘查示范”(编号:HNGSTP202302)联合资助。
关键词
构造格架
褶皱变形机制
找矿勘查启示
黄金洞金矿田
湘东北
structural framework
fold deformation mechanisms
exploration implications
Huangjindong goldfield
Northeastern Hunan
