冕宁-德昌稀土成矿带碳酸岩流体研究

通过对四川冕宁-德昌稀土矿带主要矿物中包裹体岩相学、显微测温分析与包裹体成分分析,指出由岩浆碳酸岩分异出的成矿流体为富含高密度CO2、K、Na、SO42-和多种成矿元素的超临界流体,流体以高温、高压、超高盐度、富CO2为特征,从早期到晚期流体中CO2含量增加。结合前人对碳酸岩流体、稀土矿带周边新生代盆地中无机成因CO2气藏、富钾卤水、稳定同位素和隋性气体同位素研究成果,从碳酸岩流体的性质、流体体系、碳、氦同位素组成,初步探讨了碳酸岩流体与周边新生代盆地中CO2气藏、富钾卤水的成因联系。

A Study on the Fluids in Carbonatite of the Mianning-Dechang REE Metallogenic Belt

The fluid inclusion study,including petrography,microthermometry,compositional analysis of inclusions,of carbonatite in the Mianning-Dechang REE metallogenic belt indicates that the composition of the ore-forming fluids derived from carbonatite magma is a kind of supercritical fluid with high dense CO_2,high contents of K,Na,Ca,Ba,Sr,REE,SO_4,CO_3,Cl,F.The ore-forming fluid is characterized by its high temperature,high pressure,super high salinity and rich in CO_2,with CO_2 increasing from early to late stages.In combination with the stable isotopic results and noble gas isotopic results by other researchers on the carbonatite fluid,inorganic CO_2 gas reservoir and K-rich brine reservoir in the Cenozoic basin in the adjacent area of the REE belt,the authors have discussed the genetic relationship between the fluid derived from the carbonatite and the inorganic CO_2 gas and K-rich brine in the adjacent Cenozoic basin.