华阳川碳酸岩流体包裹体研究  

A Study of Fluid Inclusion from Huayangchuan Carbonatite

作　　者：王林均[1,2] 许成[3] 吴敏[1,2] 宋文磊[3] 

机构地区：[1]中国科学院地球化学研究所地球深部物质与流体作用地球化学研究室,贵州贵阳550002 [2]中国科学院研究生院,北京100049 [3]北京大学造山带与地壳演化教育部重点实验室,北京100871

出　　处：《矿物学报》2011年第3期372-379,共8页Acta Mineralogica Sinica

基　　金：国家自然科学基金(批准号:40973040);北京大学青年人才计划项目

摘　　要：华阳川碳酸岩位于秦岭造山带与华北地块的交接部位的小秦岭,呈脉状产出,主要由方解石组成。通过流体包裹体测温和拉曼研究显示,华阳川碳酸岩流体包裹体主要由CO2-H2O两相、CO2-H2O三相(LH2O+VCO2+LCO2)和含天青石子矿物三种类型组成,并且具有中低温(138～357℃)、中低盐度(11.05%～0.43%NaCl)特征,这说明该碳酸质流体富含CO2和Sr等不相容元素,这与典型的碳酸岩流体包裹体特征相似,且该区碳酸岩C-O同位素组成也完全落在原始的火成碳酸岩范围内,并未受明显的后期热液作用,这也进一步表明,华阳川碳酸岩脉在侵位结晶前,已经发生了大量的矿物相的分离结晶,导致其富集挥发分和不相容元素,且具有温度和盐度相对较低的特征,因此它们可能是方解石的堆积体。The Huangyangchuan carbonatite is located in Lesser Qinlin which is the joint of the Qinlin Orogenic belt and North China block. It occurs as veins and principally consists of calcite. Based on the study of microthermometry and laser Raman microprobe of the fluid inclusions from the carbonatite, there are three types of fluid inclusions have observed, including two phases of CO2-H20, three phases of C02-H20 （LH2O ＋ Vco2 ＋ Leo2） and celestite-bearing in- clusion. The fluid inclusions are characterized by moderate-low temperature （138 - 357 °C ） and salinity （11.05wt% - 0. 43wt% NaC1） indicating the Huangyangchuan carbonatitic fluids are rich in CO2 and Sr. It is as same as the typical fluid inclusions in carbonatite. The carbonatite is also characterized by primary mantle-derived C- O isotopic compositions, indicating it is not affected by alteration processes. This implies that there were much abun- dant fractional crystallization of the mineral phases before the emplacements and crystallization of the Huangyang- chuang carbonatite veins, which led to the fluids enrichment in vapor and incompatible elements. Therefore their flu- id inclusions display comparatively low temperature and salinity. The Huangyangchuang carbonatite may be the cal- cite cumulates.

关 键 词：碳酸岩 流体包裹体 方解石堆积体 华阳川 

分 类 号：P579[天文地球—矿物学] P581[天文地球—地质学]