投稿时间：2020-11-24
修订日期：2021-03-08
网络发布日期：2021-05-17
中文摘要:新疆白杨河铀铍矿床是亚洲最大的铀铍矿床，矿化主要产在晚石炭世花岗斑岩与泥盆系晶屑凝灰岩的接触带以及花岗斑岩体内部。已有研究表明该矿床是多期次热液流体叠加的结果，但是关于成矿流体的来源及其成因还不清楚。文章在详细野外地质观察基础上，对白杨河矿床中矿化的和未矿化的花岗斑岩、晶屑凝灰岩进行了锂同位素及其成矿元素组成分析。结果显示，矿化的花岗斑岩和晶屑凝灰岩均富Li、U、Be、B、F等元素；未矿化的花岗斑岩与矿化的花岗斑岩δ7Li同位素组成相差不大（1.57‰~5.79‰），而未矿化的晶屑凝灰岩δ7Li同位素（22.77‰~23.96‰）与矿化晶屑凝灰岩δ7Li同位素（-6.89‰~-3.92‰）组成差异明显，显示贫7Li流体叠加。作者认为白杨河铀铍矿床的成矿流体是富含Be、U和B的流体，与花岗斑岩矿化有关的成矿流体来自岩浆分异作用，而与晶屑凝灰岩矿化有关的成矿流体可能来自深部岩浆房岩浆的分异作用。
Abstract:The Baiyanghe U-Be deposit is the largest subvolcanic U-Be deposit in Asia. Orebodies in the Baiyanghe deposit occur as fracture fillings along contact zones between the Yangzhuang granite porphyry and the Devonian volcanic rocks and also within the granite porphyry. Previous studies have revealed that the Baiyanghe U-Be deposit has experienced multiple hydrothermal alteration and mineralization, but the origin of the fluids remains unclear. Based on the detailed field geological investigation, the authors analyzed the composition of lithium isotope and ore-forming elements in the mineralized and unmineralized granite porphyry and crystalline tuff in the Baiyanghe deposit. The results show that the δ7Li isotopic composition of the unmineralized granite porphyry is similar to that of the mineralized granite porphyry (1.57‰~5.79‰), while the δ7Li isotopic composition of the unmi-neralized crystalline tuff (22.77‰~23.96‰) is significantly different from that of the mineralized crystalline tuff (-6.89‰~-3.92‰), which indicates that the ore-forming fluids of the Baiyanghe Be-U deposit were rich in Be, U, and B, with an obvious superposition of multi-stage ore-forming fluid activities. The lithium isotope results show that a part of ore-forming fluids came from the magma of the underlying deep magma chamber.
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基金项目:本文得到国家自然科学基金面上项目（编号：41972087）和中国科学院地质与地球物理研究所重点部署项目（编号：IGGCAS-201902）资助
引用文本：
朱艺婷,李晓峰,王果,杨文龙.2021.新疆白杨河铀铍矿床成矿流体深部来源的锂同位素证据[J].矿床地质,40(2):262~272ZHU YiTing,LI XiaoFeng,WANG Guo,YANG WenLong.2021.Deep sources of ore-forming fluids involved in formation of Baiyanghe U-Be deposit, Xinjiang: Evidence from lithium isotope[J].Mineral Deposits40(2):262~272
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