江西科学2025，Vol.43Issue(2)：262-270,9.DOI:10.13990/j.issn1001-3679.2025.02.007
西藏荣那超大型Cu-(Au)矿床黑云母矿物学特征及其对成矿的指示
Mineralogical Features of Biotite from the Giant Rongna Cu-(Au)Deposit in Tibet and Their Implications for Mineralization
摘要
Abstract
The Rongna Cu-(Au)deposit is located in the western segment of the Bangong Lake-Nujiang metallogenic belt in Tibet.It is a telescoped porphyry high-sulfidation epithermal deposit,and its ore-forming rock is granodiorite porphyry.Based on the occurrence and genesis of biotite,the biotite in the Rongna deposit was divided into three types:disseminated biotite in porphyry(Bt Ⅰ),phenocryst biotite in porphyry(Bt Ⅱ)and newly-born biotite(replacing hornblende)(Bt Ⅲ).The biotites from the Rongna deposit are relatively rich in Mg,with XMg values ranging from 0.71 to 0.86,XMg=Mg/(Mg+Fe),in which Fe and Mg are calculated using the mole fractions.Compared with magmatic Bt Ⅰ and Bt Ⅱ,the contents of XMg,Al2O3,SiO2 and F in hydrothermal Bt Ⅲ are higher,while the contents of TiO2,FeO and Cl are lower.The log(f(HF)/f(HCl))values of Bt ⅠⅡ are lower than those of Bt Ⅰ and Bt Ⅱ,suggesting a decrease in f(HF)/f(HCl)from the magmatic to hydrothermal stage.This could arise from the different partition behavior of F and Cl during the exsolution of fluid from melt(Cl tends to enter fluid and F tends to remain in melt during the separation of melt and fluid).The ox-ygen fugacity of the three types of biotite is located between Ni-NiO(NNO)and Fe2O3-Fe3O4(HM)buffers,indicating that the magmatic-hydrothermal system of the Rongna deposit had relatively high oxygen fugacity.However,compared with magmatic Bt Ⅰ and Bt Ⅱ,the oxygen fugacity of hydrothermal Bt Ⅲ is relatively lower,which may be related to the precipitation of magnetite.关键词
Cu-(Au)矿床/黑云母/荣那/西藏/斑岩-浅成低温热液矿床Key words
Cu-(Au)deposit/biotite/Rongna/Tibet/porphyry-epithermal deposit分类
地质学引用本文复制引用
刘通,张夏楠,李光明,秦克章,李金祥,潘家永,余可龙,赵俊兴,罗辉..西藏荣那超大型Cu-(Au)矿床黑云母矿物学特征及其对成矿的指示[J].江西科学,2025,43(2):262-270,9.基金项目
国家自然科学基金项目(42102096,42462016) （42102096,42462016）
科技部第二次青藏高原科学考察研究项目(2019QZKK0806) （2019QZKK0806）
江西省自然科学基金项目(20242BAB27002). （20242BAB27002）
