甘南阳山金矿床控矿构造的思考  

Thoughts on ore-controlling structure of the Yangshan gold deposit in southern Gansu Province,western China

作　　者：陈柏林[1,2] CHEN Bailin(Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 10008l,China;Applied Geology Research Center,China Geological Survey,Chengdu,Sichuan 610036,China)

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]中国地质调查局应用地质研究中心,四川成都610036

出　　处：《地质学报》2023年第8期2512-2533,共22页Acta Geologica Sinica

基　　金：中国地质调查局项目(编号ZD20220310,DD20191028);国家重点研发计划项目(编号2017YFC0602602);中国地质科学院院长基金项目(编号JYYWF20180602)联合资助的成果。

摘　　要：阳山金矿床位于甘肃省陇南市文县境内,其大地构造位置处于西秦岭构造带的玛曲-略阳深大断裂南侧,是西秦岭地区为数有限的大型金矿床之一。该区控矿构造复杂,经过20多年的研究仍然存在很大争议。本文通过对矿区含矿构造的调查结合区域构造环境,重新厘定了含矿构造的特征,并对该矿床控矿构造的相关问题进行了讨论。研究结果显示,阳山金矿床控矿构造是以走向NEE,倾向NNW为主的偏脆性逆冲推覆构造系统,形成于俯冲-碰撞早期的韧性变形之后。含矿构造与千枚岩的千枚理没有直接的关系,可以与千枚理近于平行,或小角度斜交,或大角度斜交,主要以倾向北的断裂为主,少量为主逆冲断层上盘的倾向南的次级反向逆冲断裂,局部为顺千枚理的层间破裂。含矿构造对岩性没有选择性,但是不同岩性岩石的不同力学性质影响了含矿构造的发育与否和发育程度。阳山金矿区进一步工作中值得思考和关注的问题:(1)矿区构造格架上葛条湾-草坪梁复背斜可能不存在,也未起控矿作用;(2)成矿后断裂对矿体空间展布的影响;(3)在勘查编录中对各种构造破碎带需要详细的描述,以明确区分含矿构造与成矿后构造,为构建控矿构造体系准备素材,为进一步找矿预测和勘查工程部署提供技术支撑。The Yangshan gold deposit is located in Wenxian County,Longnan City,Gansu Province,and its tectonic position is on the south side of Maqu-Lueyang deep fault in the western Qinling tectonic belt.It is one of the several large gold deposits in the western Qinling area.However,the ore-controlling structure is complicated,and there is still great controversy about those after over 2 decades of research.Based on the investigation of ore-bearing structures in the mining area and the regional tectonic environment,this paper redefines the characteristics of ore-bearing structures,and discusses the related problems of ore-controlling structures in this deposit.The results show that the ore-controlling structure of the Yangshan gold deposit is a brittle thrust nappe structure system with NEE strike and NNW tendency,which was formed after ductile deformation in the subduction to early collision stage.The ore-bearing structure is not directly related to phyllite,but can be nearly parallel to phyllite,oblique to a small angle or oblique to a large angle.The ore-bearing structures are mainly fault structures inclined to the north,with a little secondary thrust faults inclined to the south on the upper wall of the main thrust fault,and local interlayer fractures along phyllite.Then,ore-bearing structures have no selectivity to lithology,but different mechanical properties of different lithology affect the development of ore-bearing structures.The problems worthy of consideration and attention in the future work in the Yangshan gold mining area are:firstly,the Getiaowan-Caopingliang anticlinorium on the structural framework of the mining area may not exist,and it has not played a role in ore-controlling;secondly,post-metallogenic fault structures are well developed and have great influence on the spatial distribution of ore bodies;thirdly,detailed description of various structural fracture zones is needed in the exploration catalogue.Only in this way can we clearly distinguish the ore-bearing structure from the post-mineralizati

关 键 词：含矿构造 控矿构造 推覆构造 构造控矿模型 阳山金矿床 甘南 

分 类 号：P618.51[天文地球—矿床学]