Petrogenesis of Granites Containing Tungsten and Tin Ores in the Baiganhu Deposit, Qimantage, NW China: Constraints from Petrology, Chronology and Geochemistry

详细信息   

• 责任者：Gao Yongbao (College of Earth Science and Resources ; Chang’an University ; Xi’an 710054 ; China) ; Li Wenyuan
• 刊名：Geochimica
• 出版年：2011
• 卷期：40(4)
• 关键词：钨矿 ; tungsten ores ; 锡矿 ; tin ores ; 花岗岩矿床 ; granite deposit ; 昆仑山 ; Kunlun Mountains
• 页码：p.324-336
• 图表：illus., 3 tables, 36 refs.
• 分类号：1001
• issnNo：ISSN0379-1726
• isbnNo：CN44-1398/P

摘要

 The granites in Baiganhu deposit are closely related to W-Sn mineralization.The results of LA-ICPMS U-Pb isotope dating show that oligoclase granite containing tungsten and tin ores was formed at(429.5±3.2) Ma,and the monzonite granite was formed at(430.5±1.2) Ma.The εHf(t) values of monzonite granite vary from –2.31 to 5.57,and the T2DM varies mainly from 1188 to 1390 Ma.The εHf(t) values of oligoclase granite vary from –2.17 to 1.19,and T2DM varies mainly from 1338 to 1552 Ma.The similar Hf isotopic compositions indicate similar origins of their parental magmas.Major and trace element data of monzonite granite show that it is a weakly metaluminous or peralumious A-type granite,characterized by high ∑REE,LREE enrichment,medium to strong negative Eu anomalies,rich Y,Zr,Hf,Th and U,depleted Rb,Nb and Ta.The oligoclase granite show geochemical characteristics different from those of the monzonite granite,probably because of crystal fractionation and fluid activity during the late stages of magma evolution.Both of the granites were derived from the melting of ancient felsic crust because of mantle underplating during the extension environment.There are two ore-forming stages in the Baiganhu W-Sn deposit.In the first stage,during the intruding process of magmas containing tungsten and tin into wall rocks in Early Silurian period,the skarn-type and greisen-type tungsten ore bodies were formed in the top and contact belt of the granites.In the second stage,metals from wall rocks,such as W and Sn,were leached out by magmatic fluids of the 第 4 期 高永宝等: 东昆仑造山带祁漫塔格地区白干湖含钨锡矿花岗岩: 岩石学、年代学、地球化学及岩石成因 325 late stage magma evolution,the quartz-veined tungsten ore bodies were formed along the fractures.