南秦岭汉阴金矿田长沟金矿陆内造山期构造-蚀变岩相填图与找矿模型  

Intracontinental orogenic structure-altered lithofacies mapping and prospecting model of the Changgou gold deposit in the Hanyin gold orefield South Qinling

作　　者：杨兴科[1] 韩珂[1] 何虎军[1] 张伟胜 魏丽 贾凤仪 YANG Xingke;HAN Ke;HE Hujun;ZHANG Weisheng;WEI Li;JIA Fengyi(School of Earth Science and Resources,Chang'an University,Xi'an 710054,Shaanxi,China;Shaanxi Center of Geological Survey and Planning Research(Shaanxi Geological Exploration Fund Center),Xi'an 710068,Shaanxi,China;No.1 Geological Party,Shaanxi Bureau of Geology and Mineral Resources Exploration&Development,Ankang 725000,Shaanxi,China)

机构地区：[1]长安大学地球科学与资源学院,陕西西安710054 [2]陕西省地质调查规划研究中心(陕西省地质勘查基金中心),陕西西安710068 [3]陕西地矿第一地质队有限公司,陕西安康725000

出　　处：《地质通报》2020年第11期1715-1725,共11页Geological Bulletin of China

基　　金：国家自然科学基金项目《南秦岭金矿带典型矿床与成矿规律研究》(批准号:41872219);陕西省地勘基金项目《陕西秦岭成矿带金矿成矿规律与找矿预测》(编号:61201506280);中国地质调查局项目《陕西石泉-旬阳金矿整装勘查区关键基础地质研究》(编号:科[2014]04-02-063);《陕西石泉-旬阳金矿整装勘查区专项填图与技术应用示范》(编号:12120114014201);中央高校基本科研项目《秦岭陆内造山成矿作用与找矿建模研究》(编号:310827173702)。

摘　　要：大比例尺矿田构造-蚀变岩相填图技术是矿田构造物理化学研究和整装勘查区综合研究中逐渐形成的一项新技术。通过对南秦岭石泉-旬阳金矿整装勘查区调研和大比例尺矿田构造填图示范,认为在矿田尺度实施1∶25000构造-岩相填编图、在矿区尺度实施1∶10000或1∶5000构造-蚀变岩相填编图是可行有效的。南秦岭汉阴北部金矿田近十年来经过矿田构造-蚀变岩相填图和专题研究,找矿预测进展较大。其中,长沟金矿是近年矿田构造-蚀变岩相填图找矿和整装勘查区综合研究新发现的、受脆-韧性剪切带控制的蚀变岩型金矿床。长沟金矿床位于脆-韧性剪切带DSZ3(RF5)内。含矿岩性主要是下志留统梅子垭组糜棱岩化含黑云母变斑晶绢云母石英片岩和含石榴子石绢云母石英片岩。与成矿密切相关的蚀变主要有黑云母化、硅化、黄铁矿化、绢云母化。当黑云母变斑晶发育、石英脉密集发育,伴有黄铁矿化,且离构造破碎带80~150 m时,金矿化品位较高。成矿流体主要属中-低温、中-低盐度、低密度的NaCl-H2O-CO2体系,成矿压力为41.03~98.04 MPa,成矿深度为1.52~3.63 km。与成矿有关的花岗闪长岩脉和花岗细晶岩锆石LA-ICP-MS年龄为180.2±3.6~176.0±1.9 Ma。长沟矿区黑云母变斑晶化蚀变岩金矿石中黑云母40Ar-39Ar年龄为178.44±0.81 Ma,反等时线年龄为178.20±0.76 Ma。明确了该矿区蚀变岩成岩和金成矿时代为早侏罗世,成矿时代属于燕山期陆内。The large-scale tectonic altered lithofacies mapping technology is a new technology gradually formed in the study of the tectonics-physics-chemistry of the orefield and the comprehensive study of the whole survey area. Based on the survey of the ShiquanXunyang gold mineraliztion belt in the South Qinling Mountain and the large-scale orefield structure mapping demonstration,it is considered that the 1∶25000 tectonic-lithographic mapping implemented at the orefield scale and 1∶10000 or 1∶5000 structure-altered lithofacies mapping implemented at the mining area scale are feasible and effective. In the past ten years,the gold orefield in the north of Hanyin County,South Qinling,has made great progress in ore prospecting by structure-altered lithofacies mapping and special studies. The Changgou gold deposit in Hanyin County is a new type of altered rock type gold deposit controlled by brittle-ductile shear zones,which was discovered during comprehensive research on ore structure-altered rock facies mapping in recent years. The Changgou gold deposit is located in the DSZ3 brittle-ductile shear zone( RF5),where the lithology is mainly mylonitized biotitebearing phenocryst sericite quartz schist and garnet bearing sericite quartz schist of Lower Silurian. The alterations of the rock closely related to mineralization are biotitization,silicification,pyrite mineralization,and sericitization. Where biotite morphology is developed and quartz veins are developed densely accompanied by pyrite mineralization and is about 80~ 150 meters away from the later stage main fracture belt,the gold mineralization grade is relatively high. The ore-forming fluid mainly belongs to the medium-low temperature,medium-low salinity,and low-density NaCl-H2O-CO2 system. The ore-forming pressure is from 41.03 MPa to 98.04 MPa and the ore-forming depth is from 1.52 km to 3.63 km. The granodiorite veins and granite aplite related to mineralization measured by U-Pb zircon LA-ICP-MS have ages from 180.2±3.6 Ma to 176.0±1.9 Ma. The 40Ar-39Ar age

关 键 词：构造物理化学 构造-蚀变岩相 脆-韧性剪切带 大比例尺矿田构造-蚀变岩相填图 汉阴县长沟金矿床 陆内造山期 

分 类 号：P618.51[天文地球—矿床学] P623[天文地球—地质学]