川西可尔因地区伟晶岩型锂矿地球化学指标定位矿体的方法  

A method for locating ore bodies by geochemical indexes of pegmatite-type lithium deposits in the Ke’eryin area,western Sichuan,China

作　　者：唐文春[1] 段威 邹林 杨贵兵 张伟[1,2] 熊观 TANG Wenchun;DUAN Wei;ZOU Lin;YANG Guibing;ZHANG Wei;XIONG Guan(Geochemistry Exploration Team of Sichuan Bureau of Geology and Minerals Resources,Deyang 618000,Sichuan,China;Sichuan Deep Resource Geological Exploration Co.,Ltd.,Deyang 618000,Sichuan,China)

机构地区：[1]四川省地质矿产勘查开发局化探队,四川德阳618000 [2]四川省深地地质勘查有限公司,四川德阳618000

出　　处：《地质力学学报》2022年第5期765-792,共28页Journal of Geomechanics

基　　金：四川省地矿局科技计划项目(SCDKKJXM-2018002);四川省地矿局化探队自筹科研专项(HT-KY-2022-003)。

摘　　要：可尔因地区是松潘-甘孜成矿带的大型稀有金属矿集区之一,围绕可尔因岩体分布了大量花岗伟晶岩脉,如何在数百平方千米伟晶岩田中定位稀有金属矿脉一直是该区伟晶岩型锂稀有金属矿找矿难点之一。通过对可尔因岩体二云母花岗岩、伟晶相微斜钠长花岗岩、不同类型伟晶岩及典型矿床开展系统的岩石地球化学分析,总结了可尔因地区伟晶岩地球化学元素空间分布和变化规律,提出了寻找锂矿的特征元素指标、指示指标和品位指标等地球化学指标。特征元素指标包括Li、B、Sn、Rb、Be、Nb、Ta等元素;平面指示指标包括Cs、Tl、F、Zr、Y、ΣREE等元素及TiO_(2)/Ta、Zr/Hf、Ta/Zr、Nb/Ta、K/Na等值;垂向指示指标包括B、U、Zr、Be、Sn、Rb、Sr、Ba、Tl、In等元素。通过特征元素指标及指示指标的值和变化规律,可辅助定位稀有金属矿化伟晶岩位置,指示矿体深部延伸情况。品位指标主要包括铝饱和指数(A/CNK、A/NK)、里特曼指数(σ)、K+Na和K/Na值等,Li品位与铝饱和度呈正相关、与碱度呈负相关,品位指标的变化趋势指示了矿体中锂的富集部位。The Ke’eryin area in Sichuan province is one of the large rare metal ore concentration areas in the Songpan-Garze metallogenic belt.Numerous granite pegmatite dikes spread around the Ke’eryin mass.However,locating rare metal dikes in such a large pegmatite field has always been one of the challenges in this region.This paper summarized the geochemical element distribution in the Ke’eryin pegmatite and put forward geochemical indexes,e.g.,characteristic element indexes,indicator indexes and grade indexes,to locate rare metal ore in the Ke’eryin area based on a systematic petrogeochemical analysis of two-mica granite,pegmatite microcline albite granite,different pegmatite types and typical deposits.Characteristic element indexes include Li,B,Sn,Rb,Be,Nb and Ta,etc.Indicator indexes for lateral variation are Cs,Tl,F,Zr,Y and ΣREE elements as well as values,e.g.,TiO_(2)/Ta,Zr/Hf,Ta/Zr,Nb/Ta,K/Na,etc.,while indicator indexes for vertical variation include B,U,Zr,Be,Sn,Rb,Sr,Ba,Tl and In,etc.The variation in these indexes can be used to locate rare-metal-mineralized pegmatite,indicating ore bodies in a deep basin.Grade indexes are aluminum saturation index(A/CNK,A/NK)and rittmann index(σ),etc.Li ore grade is positively correlated with aluminum saturation but is negatively correlated with alkalinity.Grade index variation is a good indicator of lithium enrichment in ore bodies.

关 键 词：地球化学指标 伟晶岩 锂矿 矿体定位 可尔因 

分 类 号：P618.71[天文地球—矿床学] P59[天文地球—地质学]