川西李家沟伟晶岩型锂矿白云母短波红外光谱与矿物地球化学特性的相关性研究  

Examination of the Correlation Between Shortwave Infrared Spectra and Mineral Geochemical Characteristics of Muscovite in the Pegmatite-Type Lithium Deposit in Lijiagou,Western Sichuan

作　　者：韩警锐 冉凤琴 彭勃 陈燃 唐波 奉大博 杨阳[1] 赵媛 顾春进 陈浩 赵恒兵 HAN Jing-rui;RAN Feng-qin;PENG Bo;CHEN Ran;TANG Bo;FENG Da-bo;YANG Yang;ZHAO Yuan;GU Chun-jin;CHEN Hao;ZHAO Heng-bing(College of Earth and Planetary Sciences,Chengdu University of Technology,Chengdu 610059,China;Sichuan Institute of Comprehensive Geological Survey,Chengdu 610081,China;Department of Natural Resources of Sichuan Province,Chengdu 610072,China;The 5th Geological Brigade of Sichuan,Chengdu 610036,China;Sichuan Dexin Mining Resources Co.,Ltd.,Aba Tibetan and Qiang Autonomous Prefecture 624199,China)

机构地区：[1]成都理工大学地球与行星科学学院,四川成都610059 [2]四川省综合地质调查研究所,四川成都610081 [3]四川省矿床资源储量评审中心,四川成都610072 [4]四川省第五地质大队,四川成都610036 [5]四川德鑫矿业资源有限公司,四川阿坝藏族羌族自治州624199

出　　处：《光谱学与光谱分析》2025年第5期1355-1363,共9页Spectroscopy and Spectral Analysis

基　　金：基金资助:国家重点研发计划项目(2022YFC2905001);国家自然科学基金项目(42230813,42402078);四川省自然科学基金项目(2023NSFSC0791)资助。

摘　　要：李家沟花岗伟晶岩型锂矿是川西地区的超大型矿床。目前,李家沟矿床中白云母的短波红外光谱特征尚不清楚,其化学组分与光谱参数之间的相关性缺乏深入认识。本文以李家沟矿床伟晶岩中白云母为研究对象,开展显微结构观察、电子探针分析(EPMA)和短波红外光谱测量等工作。将伟晶岩中白云母划分为三个阶段:①原生白云母(MS),岩浆阶段产物,Al、K含量较高,白云母2200 nm吸收峰位(Pos2200)集中于2201~2202.8 nm,相应吸收峰的吸收深度(2200Dep)大多<0.25,伊利石结晶度(IC值)集中于1~1.5;②过渡白云母(TM),形成于岩浆-热液过渡阶段,由于富含挥发分的流体出溶导致Li元素的富集,Li2O含量为2.53%~6.22%,Pos2200集中于2200~2201 nm,2200Dep多<0.5,IC值最高(多>4);③热液白云母(HM),主要由流体交代作用形成,Pos2200最短,2200Dep多<0.4,IC值集中于2~4。李家沟伟晶岩中白云母的Al—OH吸收峰可以反映白云母Si、Al、Fe、Li等元素含量变化,从MS到TM,这些元素的含量变化和替换机制是控制白云母特征吸收峰波长位移的主要因素,而在热液阶段(HM)中控制因素以温度为主。综合研究表明,李家沟伟晶岩中白云母Al—OH特征峰吸收波长(2200~2201 nm)和伊利石结晶度(>4)可作为找矿标志。The Liajiagou deposit,a massive granite pegmatite-type lithium deposit,is located in the western part of Sichuan Province.Currently,the shortwave infrared spectroscopic properties of muscovite in the Liajiagou deposit remain unknown,and a deeper understanding of the correlation between its chemical composition and spectral characteristics is required.This study examines multiple generations and types of muscovite in the pegmatite of the Li Jiagou ore deposit.Microstructural observations,shortwave infrared(SWIR)spectroscopy,and electron probe microanalysis(EPMA)were performed.The muscovite in the pegmatite was classified into three generations:①Primary muscovite(MS),formed during the magmatic stage,is characterized by high concentrations of aluminum(Al)and potassium(K).The absorption peak of muscovite at 2200 nm(Pos2200)displays a limited variation range,ranging from 2201 to 2202.8 nm.The absorption depth at this peak(2200 Dep)often remains below 0.25.Additionally,the illite crystallinity index(IC value)typically falls within a narrow range of 1 to 1.5.②During the magma-hydrothermal transition stage,transition muscovite(TM)becomes enriched in Li elements as a result of the exsolution of volatile-rich fluids.The Li2O content in TM varies between 2.53%and 6.22%.Additionally,Pos2200 demonstrates a concentration peak centered at 2200~2201 nm.Most 2200 Dep values are below 0.5,whereas IC values remain consistently high,often exceeding 4.③Hydrothermal muscovite(HM),predominantly formed via fluid metasomatism,exhibits the shortest Pos2200 values,with 2200 Dep readings mostly below 0.4 and IC values ranging from 2 to 4.The Al—OH absorption peak of muscovite in the Lijiagou pegmatite indicates variations in the elemental composition,including Si,Al,Fe,Li,and other constituents.During the transition from the muscovite(MS)stage to the topaz-muscovite(TM)stage,changes in elemental composition and substitution mechanisms primarily influence the shift in muscovite's characteristic absorption peak wavelength.In contrast,

关 键 词：李家沟 花岗伟晶岩型矿床 白云母 短波红外 电子探针 

分 类 号：O657.33[理学—分析化学]