南秦岭双元沟铜矿床成矿斑岩的黑云母和角闪石成分特征及成矿意义  

Compositions and metallogenic significance of biotite and amphibole from fertile porphyry in the Shuangyuangou copper deposit in South Qinling

作　　者：赵江林 唐利[1] 田浩浩 赵凤芸 盛渊明 曾涛 陈龙龙 张寿庭[1,3] ZHAO Jianglin;TANG Li;TIAN Haohao;ZHAO Fengyun;SHENG Yuanming;ZENG Tao;CHEN Longlong;ZHANG Shouting(School of Geosciences and Resource,China University of Geology,Beijing 100083,China;China Shaanxi Nuclear Industry Group Comprehensive Analysis and Testing Co.,Ltd.,Xi’an 710024,China;Frontiers Science Center for Deep-time Digital Earth,China University of Geosciences(Beijing),Beijing 100083,China)

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]中陕核工业集团综合分析测试有限公司,西安710024 [3]中国地质大学(北京)深时数字地球前沿科学中心,北京100083

出　　处：《成都理工大学学报（自然科学版）》2024年第5期867-879,共13页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：国家重点研发计划(2022YFF0809902);中国地质大学(北京)求真学人项目(590223001)。

摘　　要：南秦岭山阳—柞水矿集区发育多个斑岩-夕卡岩型Cu-Mo矿床,其中双元沟斑岩型铜矿床的矿体主要赋存于岩体及其与围岩的接触带中。选取双元沟矿床的石英闪长斑岩和花岗闪长斑岩开展岩相学、电子探针和LA-ICP-MS原位微区成分分析,揭示黑云母和角闪石的成分特征及成矿指示意义。双元沟石英闪长斑岩与花岗闪长斑岩的黑云母主量成分特征相近,且具有富Mg,Al,Ti,K,F,Cl和贫Si,Na的特征。角闪石主微量元素差异较大,石英闪长斑岩中角闪石相对花岗闪长斑岩更富Si,Mg,而贫Al,Fe。两类岩体中的角闪石均具轻稀土元素富集,重稀土元素亏损的特征。石英闪长斑岩具有较高的氧逸度,位于HM(Fe_(2)O_(3)-Fe_(3)O_(4))高氧化区。两类斑岩均富挥发分,且花岗闪长斑岩的岩浆更富水(平均为5.30%),指示花岗闪长斑岩更具成矿潜力,含水量是造成二者成矿差异的主要因素。The Shanyang-Zhashui area of ore concentration is located in South Qinling,which is the site of porphyry-skarn copper-molybdenum deposits in which the ore body occurs in the porphyries,and its zone of contact with the wallrock of the Cu deposit in the Shuangyuangou porphyry.In this study,we selected quartz diorite porphyry and granodiorite porphyry from the Shuangyuangou deposit,and subjected them to petrographic analysis,electroprobe-based micro-analysis,and LA-ICP-MS analysis to reveal their composition as well as the implications of the mineralization of biotite and amphibole.The biotites of quartz diorite porphyry and granodiorite porphyry in Shuangyuangou were found to have similar compositions:they were rich in Mg,Al,Ti,K,F,and Cl,and depleted in Si and Na.The major and trace elements of the amphiboles had different compositions,whereby the amphiboles in quartz diorite porphyry had higher contents of Si and Mg,and lower contents of Al and Fe than those in the granodiorite porphyry.The amphiboles in the two types of porphyries were rich in light rare-earth elements and depleted in heavy rare-earth elements.The quartz diorite porphyry had high oxygen fugacity,and was in the high-oxidation HM zone(Fe_(2)O_(3)-Fe_(3)O_(4)).Both porphyries were rich in volatile matter,and the magma of the granodiorite porphyry had a higher water content(average,5.30%).The latter had a higher potential for mineralization,which was primarily influenced by the water content of magma.

关 键 词：秦岭造山带 双元沟矿床 黑云母 角闪石 成矿指示意义 

分 类 号：P611[天文地球—矿床学]