龙门山造山带北段黄泥坪金矿床蚀变矿化特征与SWIR勘查应用研究  

Alteration,Mineralization and Applications of Short Wavelength Infra-Red(SWIR)Technique in the Huangniping Au Deposit in Northern Longmenshan Orogenic Belt

作　　者：江宏君 陈华勇[3,4,5] 王朋 高政伟 纪冬平 吴宝鹏 程博兴 冯雨周 焦宏剑 王义忠 JIANG Hongjun;CHEN Huayong;WANG Peng;GAO Zhengwei;JI Dongping;WU Baopeng;CHENG Boxing;FENG Yuzhou;JIAO Hongjian;WANG Yizhong(Geological Party No.214,Sino Shaanxi Nuclear Industry Group,Xi’an 710100,Shaanxi,China;Shaanxi Railway Institute,Weinan 714026,Shaanxi,China;CAS Key Laboratory of Mineralogy and Metallogeny,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;University of Chinese Academy of Sciences,Beijing 100049,China;Guangdong Provincial Key Laboratory of Mineral Physics and Materials,Guangzhou 510640,Guangdong,China)

机构地区：[1]中陕核工业集团二一四大队有限公司,陕西西安710100 [2]陕西铁路工程职业技术学院,陕西渭南714026 [3]中国科学院广州地球化学研究所矿物学与成矿学重点实验室,广东广州510640 [4]中国科学院大学,北京100049 [5]广东省矿物物理与材料研究开发重点实验室,广东广州510640

出　　处：《大地构造与成矿学》2023年第6期1291-1306,共16页Geotectonica et Metallogenia

基　　金：中陕核工业集团有限公司院士工作站研究课题(YS190101);陕西铁路工程职业技术学院科研基金项目(2023KYYC-09);陕西省自然科学基础研究计划项目(2023-JC-QN-0286)联合资助。

摘　　要：黄泥坪金矿床位于扬子地块西北缘,是龙门山造山带北段新发现的一个重要的中型金矿床,研究程度较低,蚀变矿化分布特征和矿床成因仍不清楚,需要新的勘查方法和思路开展下一步找矿工作。基于详细的矿床地质和短波红外光谱(SWIR)研究,发现黄泥坪金矿床的围岩蚀变主要有黄铁矿化、毒砂化、白云母化、硅化和碳酸盐化,白云母通常呈细小鳞片状分布于毒砂和黄铁矿的周围,金主要以不可见金的形式存在于毒砂和黄铁矿中。汉树沟、山关石、柳树坪和石罐子4个矿段应属同一成矿系统,其中汉树沟和山关石矿段的蚀变矿化期次可分为早期变质成矿期和晚期热液脉成矿期,变质成矿期包括石英多金属硫化物阶段和浸染状毒砂-黄铁矿阶段,热液脉成矿期包括石英-方解石粗脉阶段和毒砂-黄铁矿-方解石细脉阶段。变质成矿期发生了第一次金矿化,热液脉成矿期发生了第二次金矿化。SWIR勘查应用研究发现,矿体上盘千枚岩和下盘变质砂岩中发育较多Al–OH吸收峰位值较大的变质成因多硅白云母,而矿化部位则主要发育Al–OH吸收峰位值较小的热液白云母,Pos2200≤2202.5nm可作为热液白云母族矿物与变质成岩白云母族矿物或者二者混合相(指变质成岩白云母族矿物占主导,含有部分热液白云母族矿物)的大致界线。同时Pos2200≤2202.5 nm,且IC值为1.0~1.5可作为黄泥坪矿床新的勘查指标。本研究可以为认识龙门山北段浅变质沉积岩容矿的金矿床成矿规律和找矿勘查提供新的科学依据。The Huangniping Au deposit,located in the northwestern margin of the Yangtze block,is an important medium-sized deposit in the northern Longmenshan orogenic belt.The alteration and mineralization features as well as the metallogenesis of the Huangniping Au deposit are still unclear,and new exploration methods and approaches are required for the future exploration.Hydrothermal alteration around the orebodies includes pyrite,arsenopyrite,sericite,silicification,and carbonatization,with the former two being Au-bearing.Four ore sections,including the Hanshugou,Sanguanshi,Liushuping,and Shiguanzi,belong to the same metallogenic system.Alteration and mineralization sequence of the Hanshugou and Sanguanzhi includes the early metamorphic and late hydrothermal veins epochs,with the former being divided into quartz-polymetallic sulfide and disseminated arsenopyrite-pyrite stages,the latter being the quartz-calcite coarse vein and arsenopyrite-pyrite-calcite veinlet stages.Gold has deposited in both of these two mineralization epochs.SWIR research reveals that metamorphic phengite is mainly distributed in the upper wall phyllite and footwall metasandstone,while hydrothermal muscovite is mainly developed in the mineralized zone,with Pos2200≤2202.5 nm as their boundary.The SWIR anomalies of Pos2200≤2202.5 nm and IC=1.0–1.5 can be the new indicators in the Huangniping Au deposit.The results obtained in this study can provide scientific basis for further understanding of ore-forming process of low-grade metamorphic sedimentary rock-hosted gold deposits and future exploration in the northern Longmenshan orogenic belt.

关 键 词：短波红外光谱 浅变质沉积岩容矿金矿床 黄泥坪金矿 蚀变矿化期次 龙门山造山带 

分 类 号：P614[天文地球—矿床学] P631[天文地球—地质学]