豫西萑香洼金矿区金钼矿化地质特征及成矿年代学  

Geological Characteristics and Ages of Molybdenum and Gold Mineralization in the Huanxiangwa Gold Deposit, Western Henan

作　　者：高亚龙[1,2] 叶会寿[3] 戴富余 牛英杰[1] 耿延光 陈志国[1] 李强 GAO Yalong;YE Huishou;DAI Fuyu;NIU Yingjie;GENG Yanguang;CHEN Zhiguo;LI Qiang

机构地区：[1]天津华北地质勘查局,天津300000 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]中国地质科学院矿产资源研究所,国土资源部成矿作用与资源评价重点开放实验室,北京100037 [4]河南省栾川县鑫鑫矿业有限公司,河南洛阳471500

出　　处：《大地构造与成矿学》2018年第2期291-304,共14页Geotectonica et Metallogenia

基　　金：项目资助:国家重点研发计划项目(2016YFC0600106)、中国地质调查局项目(1212011220869)和公益性行业科研专项经费项目(K0801)联合资助。

摘　　要：萑香洼大型金矿床位于华北陆块南缘熊耳山台隆五丈山花岗岩基西南部中元古界能耳群火山岩中。矿区主要发育金矿化,少量的钼矿化。其中金矿体主要产于NW向和近EW(NWW)向断裂带中,矿化类型主要为蚀变岩型和少量石英脉型,蚀变自矿体中心向外具分带现象,依次为黄铁绢英岩化带、黄铁钾硅化带、青磐岩化带。钼矿化主要产于靠近五丈山岩体的辉钼矿化花岗伟晶岩脉中,并被F8断裂错动破坏,和含金黄铁矿-石英细脉穿切。辉钼矿化整体较弱,多呈粗粒,浸染状、团块状或辉钼矿-石英细脉产出。为了探讨金、钼矿化之间的关系,确定二者是否是同期成矿作用的产物,作者在矿床地质特征研究的基础上,选取辉钼矿和与金矿化有关的蚀变钾长石分别开展Re-Os同位素和Ar-Ar同位素测年。结果表明,辉钼矿的Re-Os年龄为155.0±2.2 Ma,钾长石Ar-Ar坪年龄为133.2±1.3 Ma,分别与区内晚侏罗世五丈山花岗岩体、早白垩世花山花岗岩体形成时代相近,分属于不同期次构造-岩浆-流体成矿事件。结合区域构造,矿区钼矿化和金矿化分别对应于晚中生代伊佐奈歧板块俯冲弧后陆缘环境和之后的岩石圈大规模减薄的成矿动力学背景。The Huanxiangwa gold deposit in the Xiong’ershan area is located southwest of the Wuzhangshan granite and hosted by the Proterozoic volcanic rocks of the Xiong’er Group.The Xiong’ershan area tectonically belongs to the southern margin of the North China Craton.This deposit has a gold reserve of 27 tons with minor molybdenum mineralization.The gold ore bodies mainly occur in the NW-EW(NWW)trending fault zones.Gold ores mainly consist of altered rock type and minor quartz vein type.The ore related hydrothermal alteration exhibits obvious zonation.Three distinct zones can be recognized from the center out,i.e.,beresitization zone,pyritization-potassic-silicification zone,and propylitization zone.Molybdenum mineralization is relatively weak,and mainly occurs in the molybdenitebearing granitoid pegmatite vein near the Wuzhangshan granite.Molybdenite mostly occurs as coarse grain,disseminated,cloddy,or molybdenite-quartz veinlet in the granitoid pegmatite which is cut by the F8 fracture and gold-bearing pyrite-quartz veinlet.In order to delineate the temporal relationship between gold and molybdenum mineralization,two molybdenite samples from granite pegmatites and one K-feldspar sample from the wall rock of a gold-bearing quartz vein were collected for dating.The two molybdenite samples yielded Re-Os model ages of 155.0?2.2 Ma,which are similar to the emplacement age of the Late Jurassic Wuzhangshan granite.The K-feldspar sample yielded a 40Ar/39Ar plateau age of 133.2?1.3 Ma,which is similar to the emplacement age of the Early Cretaceous Huashan granite.Geochronological data indicate that the molybdenum mineralization and gold mineralization at the Huanxiangwa gold deposit are likely related to two different episodes of magmatic-hydrothermal events.

关 键 词：辉钼矿RE-OS年龄 钾长石Ar-Ar年龄 构造蚀变岩型金矿 钼矿化 萑香洼 熊耳山 

分 类 号：P597[天文地球—地球化学]