湖南杉木溪超大型花岗岩型铷矿床成因

Studys on the Geological Characteristics and Zircon Morphology of Shanmuxi Super Large Rubidium Deposit,Hunan Province

湖南杉木溪矿床是新发现的超大型铷矿床,为花岗岩体型铷矿床,岩体即为矿体。铷金属赋存在尖峰岭岩体深部的黑云母花岗岩中,铷金属品味从岩体底部向上有增加的趋势。矿化花岗岩中锆石形态特征复杂,综合其外部形态特征和内部结构研究表明锆石主体为岩浆结晶锆石,但普遍受到岩浆期后富F热液的改造作用。铷在岩浆结晶分异演化过程中在残余熔体中富集,富F热液存在会延长岩浆分异演化时限,使铷在残余熔体中大量富集,且F在岩浆热液阶段有助于Rb交代长石中的K进入晶格,最终形成花岗岩型Rb矿床。

Rubidium is an important strategic metal,which is widely used in aircraft industry.Shanmuxi deposit is a newly discovered super large rubidium deposit in Hunan Province.It is a granite type rubidium deposit.The rock body is the ore body.Rubidium metal occurs in the biotite granite in the deep part of Jianfengling rock mass,and the grade of rubidium metal increases from the bottom of the rock mass to the top.Zircons in mineralized granites are characterized by complex morphology.The study of their external morphology and internal structure shows that the zircons are mainly magmatic crystal zircons,but they are generally transformed by post magmatic F-rich hydrothermal solution.Rubidium is enriched in residual melts in the process of magma crystallization and differentiation evolution.The existence of F-rich hydrothermal solution will prolong the time limit of magma differentiation and evolution,which makes rubidium enriched in residual melts.In addition,F helps K in Rb metasomatic feldspar to enter the lattice in the magmatic hydrothermal stage,and finally forms granite Rb deposits.