新疆阿尔泰伟晶岩型锂矿床磷的地球化学行为及其对锂成矿作用的指示意义  

Geochemical behavior of phosphorus and its implication for lithium mineralization in the pegmatite-type lithium deposit in Altai,Xinjiang

作　　者：陈剑争 张辉[3] 唐勇[3] 吕正航[3] 王惊涛 CHEN JianZheng;ZHANG Hui;TANG Yong;L ZhengHang;WANG JingTao(School of Jewelry,City Polytechnic of Shenzhen,Shenzhen 518116,China;School of Jewelry,Shenzhen Institute of Technology,Shenzhen 518116,China;State Key Laboratory for Critical Mineral Research and Exploration,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China)

机构地区：[1]深圳城市职业学院珠宝学院,深圳518116 [2]深圳技师学院珠宝学院,深圳518116 [3]中国科学院地球化学研究所,关键矿产成矿与预测重点实验室,贵阳550081

出　　处：《岩石学报》2024年第9期2925-2943,共19页Acta Petrologica Sinica

基　　金：国家自然科学基金重点项目(9196222);第三次新疆综合科学考察项目(2022xjkk1302);深圳技师学院校级科研项目(2314006)联合资助.

摘　　要：新疆阿尔泰造山带是我国重要的伟晶岩型稀有金属成矿带,分布有不同规模的多个伟晶岩型锂矿床,目前尚不明确岩浆-热液演化过程中磷的地球化学行为及其对锂成矿作用的指示意义。本文通过对可可托海3号脉、小虎斯特91号脉和塔拉提1号脉中碱性长石、磷灰石和磷锰(铁)锂矿等含磷矿物的微区结构和化学成分的对比研究,探讨上述科学问题。研究结果显示,随着岩浆分离结晶作用进行,磷逐渐在残余岩浆中富集,到达一定程度后会出现磷酸盐熔体与硅酸盐熔体的不混溶作用,由于锂更加倾向于进入磷酸盐熔体中,因此会形成磷锰(铁)锂矿等富锂的磷酸盐矿物。可可托海3号脉Ⅱ带中出现骸晶结构富锰磷灰石可能是由于岩浆过冷导致晶体快速结晶所致。此外,已经形成的磷锰(铁)锂矿等易被更晚期出溶的岩浆流体交代从而形成一系列复杂的次生磷酸盐矿物。The Altai orogenic belt is an important pegmatite-type rare metal metallogenic belt,with multiple pegmatite-type lithium deposits of various scales in Xinjiang,China.Currently,it is unclear about geochemical behavior of phosphorus during the magma-hydrothermal evolution and its indicative significance for lithium mineralization.This paper conducted a comparative study on the microstructure and chemical composition of phosphate-bearing minerals such as alkaline feldspar,apatite and lithiophilite(triphyline)in the Koktokay No.3 pegmatite,Xiaohusite No.91 pegmatite and Talati No.1 pegmatite,aiming to explore the above mentioned scientifical issues.The research results show that phosphorus gradually accumulates in the residual magma with the magma fractional crystallization.When it reaches a certain extent,immiscibility occurs between the phosphate melt and the silicate melt,and Li is preference for entering into the phosphate melt,leading to the formation of lithium-rich phosphate minerals such as lithiophilite(triphyline).The crystallization of Mn-rich apatite with skeletal texture in the zone II of Koktokay No.3 pegmatite may be attributed to rapid crystallization caused by magma undercooling.Moreover,the already formed lithiophilite(triphyline)are easily altered by the exsolved magmatic fluids in the later stage,resulting in a series of complex secondary phosphate minerals.

关 键 词：岩浆-热液演化过程 锂成矿作用 磷灰石 磷锰锂矿 碱性长石 阿尔泰伟晶岩 

分 类 号：P578.922[天文地球—矿物学] P588.131[天文地球—地质学] P618.71