• 首页
  • 学报简介
  • 编委会和伦理
  • 投稿指南
  • 订阅指南
  • 过刊浏览
  • 在线投稿
  • 联系我们
  • 网络预出版
  • English

本文将参加年度优秀论文评选,如果您觉得这篇文章很好,请投下您宝贵的一票,谢谢! 支持(7)   不支持(0)

LCT型伟晶岩及其锂矿床成因概述
投稿时间:2021-08-16  修订日期:2021-09-10  点此下载全文
引用本文:张辉,吕正航,唐勇.2021.LCT型伟晶岩及其锂矿床成因概述[J].地质学报,95(10):2955-2970.
Zhang Hui,Lü Zhenghang,Tang Yong.2021.A review of LCT pegmatite and its lithium ore genesis[J].Acta Geologica Sinica,95(10):2955-2970.
DOI:10.19762/j.cnki.dizhixuebao.2021093
摘要点击次数: 1149
全文下载次数: 1831
附件
作者单位E-mail
张辉 中国科学院地球化学研究所地球内部物质高温高压院重点实验室贵州贵阳550081 zhanghui@mail.gyig.ac.cn 
吕正航 中国科学院地球化学研究所地球内部物质高温高压院重点实验室贵州贵阳550081  
唐勇 中国科学院地球化学研究所地球内部物质高温高压院重点实验室贵州贵阳550081  
基金项目:本文为国家自然科学基金委“战略性关键金属超常富集成矿动力学”重大研究计划、国家自然科学基金项目 (编号 91962222、41873030)联合资助成果。
中文摘要:花岗伟晶岩具有与低共熔花岗岩相似的矿物和化学组成,通常与高分异花岗岩具有成因联系。花岗伟晶岩划分为富Li Cs Ta (LCT)、富Nb Y F (NYF)和混合的LCT+NYF型,其中LCT型伟晶岩以过铝质,富集助熔组分 (H2O、F、P、B)、稀有元素 (Li、Rb、Cs、Nb、Ta、Be、Sn),极其低的Nb/Ta比值 (<5)为特征。通常LCT型伟晶岩显示内部分带,主要包括边界带、壁带、中间带和核部带;此外,可能还发育交代体、层状细晶岩和晶洞。大多数LCT型伟晶岩形成与(同造山) 晚造山的过铝质S型、I型或混合的S+I型花岗岩具有成因联系。对于壳源沉积岩小比例部分熔融直接形成的伟晶岩,通常形成于伸展背景下的晚造山和造山后阶段,侵入于典型的低压角闪岩 高绿片岩相的变沉积岩中。伟晶岩外带 (包括边缘带、壁带、细晶岩)中的细粒和细晶岩结构、UST (单向固结结构)是液相线过冷所致,而伟晶岩内带 (中间带、核部带)中粗大矿物形成、矿物分带以及稀有金属矿物的饱和结晶是助熔组分 (H2O、B、P、F)、稀有金属 (Li、Rb、Cs、Be、Nb、Ta)通过组成带状纯化方式在边界层聚集的结果。伟晶岩分离结晶作用的开始与液相线过冷状态密切相关,晶体成核延迟、晶体生长速率、晶体成核密度取决于液相线过冷程度(△T)。针对LCT型伟晶岩,已提出的稀有金属成矿机制主要有分离结晶作用、岩浆不混溶、超临界流体和组成带状纯化。对于全脉矿化锂辉石伟晶岩成因,尚不清楚是岩浆液态分离还是Li强烈分配进入流体相所致?
中文关键词:组成特征  结构分带  岩石成因  成矿机制  LCT型伟晶岩
 
A review of LCT pegmatite and its lithium ore genesis
Author NameAffiliationE-mail
Zhang Hui Key Laboratory of High temperature and High pressure Study of the Earths Interior, Institute of Geochemistry, ChineseAcademy of Sciences, Guiyang, Guizhou 550081, China zhanghui@mail.gyig.ac.cn 
Lü Zhenghang Key Laboratory of High temperature and High pressure Study of the Earths Interior, Institute of Geochemistry, ChineseAcademy of Sciences, Guiyang, Guizhou 550081, China  
Tang Yong Key Laboratory of High temperature and High pressure Study of the Earths Interior, Institute of Geochemistry, ChineseAcademy of Sciences, Guiyang, Guizhou 550081, China  
Abstract:Granitic pegmatite shares similar modal and chemical compositions with eutectic granite, and has a genetic links with the highly fractionated granite. The LCT family, NYF family, and mixed LCT+NYF family pegmatites were classified petrogenetically, in which LCT pegmatites are peraluminous, characterized by enrichment of rare and alkali elements (Li, Rb, Cs, Be, Sn) and fluxing components (H2O, F, P, B), and very low Nb/Ta ratios (<5). In general, LCT pegmatite shows internal textural zonation, including the border, wall, intermediate and core zones; in addition, some of pegmatites maybe develop replacement bodies, layered aplites and miarolitic cavities. Most of LCT pegmatites intruded into metasedimentary rocks, typically at low pressure amphibolite to upper greenschist facies under tectonic setting of late syn collision to early post collision with respect to enclosing rocks. Aplitic textures in the outer zone (including border, wall zones and aplite) of pegmatites and UST (unidirectional solidification texture) have resulted from the liquidus undercooling of viscous granitic liquids prior to the onset of crystallization, while increasing crystal size in the internal zones (including intermediate and core zones), mineral zonations and crystallization of rare metal minerals have originated from a flux enriched (H2O, F, P, B) and pile up of rare metal (Li, Rb, Cs, Be, Nb, Ta) boundary layer of liquid developed adjacent to the crystallization front by constitutional zone refining CZR mechanism. The onset of crystallization is closely related to liquidus undercooling state, while nucleation delay, crystal growth rate and nucleation density are dependent on the degree of liquidus undercooling. Up to now, the four main metallogenic mechanism proposed for pegmatite type rare metal deposits include fractional crystallization, magmatic immiscibility, supercritical fluids and constitutional zone refining (CZR). For unzoned Li pegmatitic deposit (or whole vein Li mineralized pegmatite), ore genesis is unclear as it could have resulted either from the magmatic immiscibility or Li strongly partitioning into magmatic fluids.
keywords:composition  textural zonation  petrogenesis  metallogenic mechanism  LCT pegmatite
查看全文  查看/发表评论  下载PDF阅读器
您是第116415442位访问者  京ICP备05032737号-7  
版权所有:《地质学报》中文版
主管单位:中国科学技术协会 ; 主办单位:中国地质学会
地  址: 北京市西城区百万庄大街26号; 邮编:100037 ; 电话:010-68999025; E-mail: dizhixuebao@163.com
本系统由北京勤云科技发展有限公司设计 

京公网安备 11010202007916号

WeChat