南秦岭石泉-汉阴金矿带控矿构造特征与矿床成因探讨

石泉-汉阴成矿带是南秦岭重要的金成矿潜力区，是秦岭金成矿带的重要组成部分。为了查明区内与成矿有关的多期次构造发育特征及其对金成矿的控制作用，并进一步探讨矿床成因，本文选取石泉-汉阴成矿带内最具代表性的黄龙、长沟和金斗坡三个金矿床作为研究对象，通过详尽的野外及井下地质调研、室内显微构造观察及同位素追踪相结合的研究方法，探讨了该成矿带内的构造活动期次，确定了与成矿有关构造体系的性质，取得的主要认识有：（1）研究区与成矿关系密切的共有四期构造活动，分别为成矿前的韧性剪切构造（S1）、成矿早期的韧性剪切构造（S2）、主成矿期牛山-凤凰山隆起形成的拆离滑脱构造（S3）以及成矿期后的脆性构造；（2）成矿期早期韧性剪切构造中矿化现象并不显著，主要对区内矿床的成矿物质起到了预富集作用，而成矿主期与滑脱构造同时期的由岩浆分异而来的含矿热液叠加在早期矿化带之上才形成了区内的金矿床，其成因为岩浆期后热液型金矿；（3）成矿早期的韧性剪切构造形成于晚三叠世华北与扬子两大板块碰撞拼合的造山作用，主成矿期次拆离滑脱构造活动则为板内演化阶段由伸展塌陷造成的差异隆起所致。

Discussion on the ore-controlling structural features and ore genesis of the Shiquan-Hanyin metallogenic belt in the South Qinling

The Shiquan-Hanyin metallogenic belt is an important gold potential metallogenic area in the South Qinling. Taking the Huanglong, Changgou and Jindoupo typical deposits as the research objects. The purpose of this paper is to find out the relationships between the multiple periods of tectonic-magmatic activities and metallogenies, and further to reveal the genesis of the gold deposit. Based on a combined study of detailed field, gallery and drilling investigations, and indoor analyses of their microstructures, four period of tectonic activities related to mineralization were identified as three period of foliations and one later fault damage zone. The earlier S2 penetrative foliation was controlled by a NW- nearly EW-trending ductile shear zone, and the later NE-trend and gentle NW-dip S3 impenetrable flow cleavage occurred around the Niushan-Fenghuangshan uplift. In-situ S isotopic compositions (ranging from 6.94‰ to 14.13‰) in the three deposits show marked fractionation and different S sources during their ore-forming process and sulfur sources. Hydrogen and oxygen isotopic analysis results (δ18Owater: 4.1‰~9.3‰, δD: -93.2‰~-80.1‰) indicate that the mineralization fluids of the deposit are formed by the mixing of magmatic fluid and meteoric water. Our results suggest that there were two mineralization events in the study area: one was ductile shear related gold mineralization controlled by S2 foliation, the other was the later ore-bearing magmatic hydrothermal mineralization controlled by S2 and S3 foliation. Therefore, we suggest that the gold deposits developed in the study belong to the post magmatic hydrothermal type, the ore-forming materials are mainly derived from the regional formation, and the magmatic activities have provided the fluid and the heating source for the deposits. In summary, we think the regional metallogenic events were caused by the collision between North China Block and Yangtze Block and later differential uplift during the intra-continental extension stage.