摘要
角西矿床是班公湖-怒江成矿带上目前发现的首例石英脉型钨矿床。本文对该矿床的地质特征及黑钨矿微量、稀土元素进行了系统的研究。结果表明,角西矿床主要发育与中新世花岗岩密切相关的含黑钨矿(±白钨矿)石英脉,矿脉主要受张性裂隙控制,宽度在0. 02～2m之间,"五层楼"分带模式较为明显,蚀变类型主要为云英岩化和角岩化。矿化可以分为氧化物阶段、硫化物阶段和萤石-碳酸岩阶段。与华南同类型矿床相比,角西黑钨矿的稀土元素含量极低(∑REE=0. 560×10^(-6)～1. 186×10^(-6)),具有较为明显的正Eu异常。黑钨矿中相对富集Sc元素(平均31. 15×10^(-6))的特征表明成矿流体富含F-和/或PO_4^(3-)离子。以上研究成果不仅有助于加深该矿床成因的认识,而且为后续矿床勘查提供了重要信息。
Jiaoxi deposit is the first discovered quartz-vein type tungsten deposit in the western Bangong-Nujiang metallogenic belt, which contains 39100 tons of mineral resources with a WO3 grade of 0.09%~3.20%. It provides a unique opportunity to learn more about quartz-vein type tungsten deposit in the orogenic belt. Based on the field geological investigation, petrographical and mineralogical studies, this paper revealed the geochemistry features of the wolframite and the geological characteristics of this deposit. Our research results indicate that alterations of greisenization, silicification as well as contact metamorphism (hornfels) are well developed in this deposit, especially the first one. The distribution of W mineralization is mainly controlled by tensional fractures which filled with wolframite and/or scheelite-bearing hydrothermal veins. Those veins have a width range of 0.02~2m, and mainly developed in shales. Similar to the "Five-floor" model, a vertical zonation in this deposit is clear. The mineralization of this deposit is mainly attributed to three stages:the oxides stage (wolframite, beryl, muscovite and quartz), the sulfides stage (galena, sphalerite, and chalcopyrite) and the fluorite-carbonate stage (scheelite, fluorite, quartz, and carbonates). Compared to the typical quartz-vein type tungsten deposits in South China, wolframites in Jiaoxi have extremely low contents of REE (∑REE=0.560×10^-6~1.186×10^-6) and obvious positive Eu anomalies. The positive Eu anomaly of the wolframite maybe related to the redox condition of the ore-forming liquids. The relatively enriched Sc contents in the wolframite (mean=31.15×10^-6) indicates that the F^- and/or PO4^3- in the ore-forming liquid were enriched.These results not only provide important informations for further exploring, but also deepen the understanding of the ore genesis.
作者
王勇
王立强
范源
李申
旦真王修
郑斯伦
高腾
WANG Yong;WANG LiQiang;FAN Yuan;LI Shen;DANZHEN WangXiu;ZHENG SiLun;GAO Teng(School of Earth Sciences and Resources, China University of Geosciences ( Beijing) , Beijing 100083 , China;MNR Key Ixiborator) of Metallogenv and Mineral Assessment, Institute of Mineral Resources, CAGS, Beijing 100037 , China;Geothermal Geology Team , Bureau of Geology and Exploration of Tibet, Lhasa 850000, China;College of Earth Sciences, Chengdu University of Technology,Chengdu 610059 , China)
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2019年第3期724-736,共13页
Acta Petrologica Sinica
基金
国家自然科学基金项目(41873046)
中国地质调查局地质调查项目(DD20160026)
国家留学基金委出归国留学人员基金项目(201806400017)联合资助
关键词
矿床地质特征
微量元素地球化学
石英脉型黑钨矿矿床
角西矿床
班公湖-怒江成矿带
Geological characteristics
Trace element geochemistry
Quartz-vein type tungsten deposit
Jiaoxi deposit
Bangong-Nujiang metallogenic belt
