沉积与特提斯地质2024，Vol.44Issue(4)：723-739,17.DOI:10.19826/j.cnki.1009-3850.2024.05004
西藏努日Cu-W-Mo矿床白钨矿原位微量元素、Sr同位素特征及其指示意义
In situ trace-element and Sr isotopic characteristics of scheelite and their implications for the genesis in the Nuri Cu-W-Mo deposit,Xizang
摘要
Abstract
The Nuri deposit in Xizang is currently the only large deposit with Cu-W-Mo mineralization discovered in the Gangdese metallogenic belt.However,since its discovery in the last century,its genetic type has been highly controversial.Based on geological features,this study precisely classifies the metallogenic stages of the deposit.As study objects,two types of scheelite(hereinafter referred to as Sch-A and Sch-B)in the oxide stage and quartz-sulfide stage are analyzed to investigate the origins of the metallogenic fluids,the deposit's evolutionary process,and its genesis utilizing Sr isotope and LA-ICP-MS trace element analyses.Scanning electron microscopy-cathodoluminescence(SEM-CL)reveals that Sch-A has two generations,with dark homogeneous Sch-A1 being irregularly replaced by light homogeneous Sch-A2;while Sch-B has a"core-edge"structure,with Sch-B1 possessing dark gray uniform growth rings in the core and light gray homogeneous Sch-B2 in the edge.The distribution pattern of rare earth elements standardized by chondrite in Sch-A and Sr isotope data indicate that the ore-forming fluid originated from granodiorite porphyry in the early stage,and in the late stage,mixed with surrounding rock materials due to strong water-rock interactions,which is a key mechanism for the massive precipitation of scheelite.The scheelite in this study has high Mo and low Sr contents,which is consistent with the characteristics of magmatic-hydrothermal scheelite.Therefore,combining the trace-element and Sr isotope geochemical characteristics exhibited by Nuri scheelite in this study and the indications of the source of ore-forming fluid,the evolutionary process,and the genesis of the deposit,all of these indicate that the Nuri deposit belongs to the porphyry-skarn type deposit.关键词
原位微量元素/原位Sr同位素/斑岩-夕卡岩型矿床/努日/冈底斯成矿带Key words
in situ trace element/in situ Sr isotope/porphyry-skarn type deposit/Nuri/Gangdese metallogenic belt分类
天文与地球科学引用本文复制引用
吴志山,汤立伟,巴桑元旦,陈文庆,陈斌,杜庆安,侯海峰,缪恒毅..西藏努日Cu-W-Mo矿床白钨矿原位微量元素、Sr同位素特征及其指示意义[J].沉积与特提斯地质,2024,44(4):723-739,17.基金项目
国家重点研发计划项目(2021YFC2901903,2023YFC2906805) （2021YFC2901903,2023YFC2906805）
中国冶金地质总局地质综合研究项目([2022]CMGBDZYJ005) （[2022]CMGBDZYJ005）
中国地质调查局地质调查项目(DD20240069,DD20240014) （DD20240069,DD20240014）
