流体包裹体在砂岩型铀矿成矿流体研究中的应用——以鄂尔多斯南部铀矿化区为例  

Research and Demonstration of Fluid Inclusions in Sandstone-type Uranium Ore-forming Fluid——A Case of Study in Uranium Mineralization Area of Southern Ordos

作　　者：邱林飞[1,2] 张字龙[1] 孙祥[1] 贺锋[1] QIU Lin-fei;ZHANG Zi-long;SUN Xiang;HE Feng(Beijing Research Institute of Uranium Geology,CNNC Key Laboratory of Uranium Resource Exploration and Evaluation Technology,Beijing 100029,China;School of Earth Sciences,East China University of Technology,Nanchang 330013,China)

机构地区：[1]核工业北京地质研究院中核集团铀资源勘查与评价技术重点实验室,北京100029 [2]东华理工大学地球科学学院,江西南昌330013

出　　处：《东华理工大学学报（自然科学版）》2020年第4期301-312,共12页Journal of East China University of Technology(Natural Science)

基　　金：中国核工业地质局项目(20190115,20193702)。

摘　　要：流体包裹体是目前研究成矿流体最直接、有效的方法。以鄂尔多斯南部典型铀矿化区为例,在野外地质调查工作的基础上,采集典型的富铀矿石进行流体包裹体研究。研究表明,鄂尔多斯盆地南部铀矿化与油气流体活动密切相关,直罗组含矿砂岩至少经历了两期次的油气充注过程,第1期以显示浅黄绿色荧光的中轻质油为主,第2期以显示浅蓝色荧光的轻质油和气为主,在热液活动后发生了大规模的裂解。砂岩成岩后发育2至3期次流体包裹体,第1期次主要为纯液相盐水包裹体和气液比小于5%富液盐水包裹体组合,沿石英加大边内侧成带状分布,包裹体均一温度为105~114℃;第2期和第3期主要为纯液相盐水包裹体、油气包裹体和气液比小于5%的富液盐水包裹体组合,沿切穿碎屑石英颗粒及其加大边,或切穿多个碎屑石英颗粒的成岩期后微裂隙成带状分布的,部分与黑色矿物包裹体共生,均一温度分别集中于60~80℃和90~120℃两个温度段。盐度变化范围较宽,反映了不同性质的流体经历了混合与演化。Fluid inclusions are currently the most direct and effective method for studying ore-forming fluids.The typical uranium mineralization area is taken as an example in the south of Ordos.Based on the field geological survey,the typical uranium-rich ore samples were used to study the fluid inclusions.The results showed that uranium mineralization in the southeastern Ordos Basin is closely related to oil-gas fluid activities.The ore-bearing sandstone of the Zhiluo Formation has been filled two stages of oil-gas at least.In stage 1,it is mainly light oil showing yellow-green fluorescence.In stage 2,it is mainly light oil-gas showing blue fluorescence,and large-scale cracking occurred in later stage.Two or three stages of fluid inclusions are developed.The first stage FIA(fluid inclusion assemblage)is a pure liquid inclusions and some liquid-rich fluid inclusions with gas-liquid ratios of less than 5%,which are distributed along the overgrowth of quartz edge.The homogenization temperature of these fluid inclusions are between 105℃and 114℃.The second stage FIA is pure liquid fluid inclusions+oil-gas fluid inclusion+liquid-rich fluid inclusions with gas-liquid ratios of less than 5%.These fluid inclusions are distributed along the micro-fractures which are cutting through the quartz particles and their overgrowth edges or multiple quartz particles.Sometimes,the fluid inclusions are intergrowth with the black mineral inclusions,and their homogenization temperatures are concentrated in 60~80℃and 90~120℃.The salinity varies in a wide range,which suggests that ore forming fluids may undergo mixing and evolution from different properties of fluids.

关 键 词：流体包裹体 成矿流体 砂岩型铀矿 鄂尔多斯南部 

分 类 号：P619.14[天文地球—矿床学]