地质学报2023，Vol.97Issue(11)：3766-3785,中插46-中插52,27.DOI:10.19762/j.cnki.dizhixuebao.2023366
稀有金属花岗岩结晶分异过程中铷的富集与成矿:来自江西甘坊岩体的矿物学证据
Rb mineralization during magmatic differentiation:Insight from mineralogical study on the Ganfang rare metal granite,Jiangxi Province
摘要
Abstract
The Rb mineralization is associated with rare metal granites.However,widespread hydrothermal alteration in the late evolution of rare metal granites makes it difficult to distinguish the magmatic process from the hydrothermal process.It is still unclear whether the rare metal mineralization is dominated by magmatic differentiation or hydrothermal metasomatism.The Ganfang intrusion in the Jiangxi Province is an important rare metal metallogenic area,where a series of Li-Rb rare metal deposits(mineralization)have been discovered,and the mineralization mechanism of rare metals is not yet clear.This paper takes both granite-type Rb(Baiguo,Dagang,and Nanmukeng)and aplite-type Rb(Fuhua,Tongan)mineralization from the Ganfang intrusion for case studies.The detailed mineralogy texture and composition of feldspars and micas have been analyzed by automatic mineral scanning system,electron probe and LA-ICP-MS.The results show that micas are the main carriers of Rb(1683×10-6～12047×10-6),and the contents of Rb in feldspars are lower.The Rb content of K-feldspar is 1683×10-6～4051×10-6,whereas albite contains almost no Rb concentration(1.82 × 10-6～89.94×10-6).The Rb-bearing micas transfer from muscovite,though Li-phengite and zinnwaldite,to lepidolite,in which substituted mechanisms for Li are 2Li++ⅣSi4+↔ⅥAl3++ⅥAl3++□ and Li++Fe2+↔ ⅥAl3++□,and for Rb is Rb+/Na/Cs+↔K.The mineral textures and compositions record both magma crystallization differentiation and fluid metasomatism for Ganfang granites;however,the former was the key enrichment mechanism for Rb as well as Li.关键词
稀有金属/花岗岩/铷/富集机制/甘坊岩体/江西Key words
rare metals/granite/Rb/enrichment mechanism/Ganfang granite/Jiangxi Province引用本文复制引用
徐净,侯文达,王力圆,赵太平,陈素余,田立明..稀有金属花岗岩结晶分异过程中铷的富集与成矿:来自江西甘坊岩体的矿物学证据[J].地质学报,2023,97(11):3766-3785,中插46-中插52,27.基金项目
本文为南京大学内生金属矿床成矿机制研究国家重点实验室(编号2021-LAMD-K07)和中国地质调查局花岗岩成岩成矿地质研究中心开放基金(编号PMGR202004)联合资助的成果. （编号2021-LAMD-K07）
