伟晶岩型锂矿床研究现状及其在中国西部的找矿前景  

Research Status of Pegmatite-hosted Li Deposits and Their Exploration Prospect in West China

作　　者：孔会磊 李文渊[2] 任广利[2] 李侃[2] 王志华[2] 赵辛敏[2] 张江伟 彭素霞[2] KONG Huilei;LI Wenyuan;REN Guangli;LI Kan;WANG Zhihua;ZHAO Xinmin;ZHANG Jiangwei;PENG Suxia(Chinese Academy of Geological Sciences,Beijing 100037,China;Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits,MNR,Xi'an Center of China Geological Survey,Xi’an 710054,Shannxi,China)

机构地区：[1]中国地质科学院,北京100037 [2]中国地质调查局西安地质调查中心,自然资源部岩浆作用成矿与找矿重点实验室,陕西西安710054

出　　处：《西北地质》2023年第1期11-30,共20页Northwestern Geology

基　　金：国家重点研发计划课题“西部锂、铍等战略性金属矿产资源成矿规律与预测评价”(2019YFC0605201);第二次青藏高原综合科学考察研究专题“昆仑-阿尔金-柴北缘成矿带战略储备综合评估”(2019QZKK0806);中国地质调查局项目“西昆仑大红柳滩-甜水海地区大型矿产资源基地综合调查”(DD20190143);“西北地区铜镍稀有金属等矿产地质调查”(DD20221691)联合资助。

摘　　要：锂现为全球战略性关键金属矿产,花岗伟晶岩型锂矿是锂资源的重要类型之一,也是当前国际矿床学的研究热点。花岗伟晶岩划分为LCT(Li-Cs-Ta)、NYF(Nb-Y-F)及二者混合的LCT+NYF型,其中LCT型伟晶岩富集稀有元素Li、Rb、Cs、Be、Ga、Sn、Ta、Nb及B、P、F等助熔剂,通常与伸展背景下的晚造山和造山后阶段过铝质S型花岗岩具有成因联系。笔者分析了全球伟晶岩型锂矿床的时空分布特征,发现锂矿成矿事件主要发生在超大陆会聚造山作用的中晚期。研究表明中国花岗伟晶岩型锂矿空间分布相对集中,主要分布在9个锂成矿带,成矿期以三叠纪为主。花岗质岩浆结晶分异和下地壳物质低程度的部分熔融是伟晶岩两种主要的形成方式。稀有金属伟晶岩的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。总结分析了中国西部西昆仑、川西松潘-甘孜、阿尔泰等3个典型伟晶岩型锂矿带的的成矿特点、分布特征、研究进展及找矿前景,并提出了构造-岩浆-变质-成矿的耦合关系是制约锂成矿过程和富集规律的关键科学问题。Lithium has become an important strategic critical metal in the world,and the granitic pegmatite type lithium deposit is one of the important types of lithium resources,which is also a popular interest in the current international ore deposit research.The granitic pegmatites are classified into LCT(Li-Cs-Ta),NYF(Nb-Y-F)and mixed LCT+NYF type.The LCT type pegmatites are characterized by enrichment of rare elements Li,Rb,Cs,Be,Ga,Sn,Ta>Nb and fluxing components B,P,F,usually related to late orogenic and post-orogenic per-aluminous S-type granites in extensional background.In this paper,we review the temporal and spatial distribu-tion characteristics of pegmatite type lithium deposits in the world.It is noted that the lithium mineralization events mainly occurred in the middle and late period of convergent orogeny associated with the supercontinent assembly.The study shows that the spatial distribution of granitic pegmatite lithium deposits in China is relative-ly concentrated,mainly distributed in nine lithium metallogenic belts,of which the main mineralization period is Triassic.Fractional crystallization of granitic magma and partial melting of lower crust material are the two sig-nificant formation modes of pegmatites.The four metallogenic mechanism of rare metal pegmatite mainly in-clude fractional crystallization,magmatic immiscibility,supercritical fluids and constitutional zone refining(CZR).We summarize the metallogenic characteristics,distribution characteristics,research progress and explo-ration prospect of the three typical pegmatite type lithium metallogenic belts,West Kunlun,Songpan-Ganze and Altay,in western China.The coupling relationship of structure-magmatism-metamorphism-mineralization is the key scientific problem that restricts the mineralization process and enrichment regularity of lithium.

关 键 词：锂矿床 LCT型伟晶岩 成矿机制 关键金属 锂矿带 

分 类 号：P618.71[天文地球—矿床学] P612[天文地球—地质学]