投稿时间：2015-05-14
修订日期：2016-02-20
网络发布日期：2016-06-30
中文摘要:蒙其古尔铀矿床为大型层间氧化带砂岩型铀矿床,前人对其成矿流体来源的研究相对较少。为探讨其成矿流体的性质和来源,笔者利用显微测温学和激光拉曼光谱方法,对其流体包裹体的温度、盐度、密度和成分进行了系统的分析研究,并对其成矿流体的氢、氧同位素及含矿目的层砂岩方解石胶结物的碳、氧同位素组成特征进行了研究。研究表明,该矿床流体包裹体主要有气烃包裹体、液烃包裹体和盐水包裹体,成群分布于砂岩粒间方解石胶结物中,或沿切穿石英颗粒的微裂隙呈线状或带状分布,均一温度为56~76℃,盐度w(NaCleq)为1.23%~19.84%,密度为0.99~1.12 g/cm3,气体成分以CH4为主;成矿流体的δD(H2O)V-SMOW=-93.0‰~-48.3‰,δ18O(H2O)V-SMOW=-10.3‰~-5.1‰,方解石胶结物的δ13CV-PDB=-10.9‰~-7.2‰,δ18OV-SMOW=17.6‰~24.9‰。上述特征揭示出蒙其古尔铀矿床成矿流体是由大气降水性质的地表水和煤系地层有机质脱羧基作用产生的有机酸及伴生的CH4等还原性气体(煤型气)两部分组成,具有低温、盐度跨度大、中等密度及多期叠加等特点,明显有别于深部油气大规模充注。地表含铀含氧水层间渗入与煤系地层产生煤型气等还原性渗出流体的共同作用,形成了蒙其古尔铀矿床。
Abstract:The Mengqiguer uranium deposit is a large interlayer oxidation zone type uranium deposit, nevertheless, the research on its metallogenic fluids has been very insufficient. In order to discuss the characteristics and source of metallogenic fluids, the authors used microthermometry and laser Raman spectrum of fluid inclusions to systematically analyze the homogenization temperatures, salinities, densities and compositions of its fluid inclusions. The H-O isotope of its metallogenic fluids and the C-O isotopes of its carbonate cement from ore-bearing sandstone were also investiged. The results show that the fluid inclusions in the Mengqiguer uranium deposit include gas-hydrocarbon inclusions, liquid-hydrocarbon inclusions, brine-inclusions which are distributed in intergranular calcite filling the sandstone in groups and microcracks cutting quartz grains in banding or linear form, the homogenization temperatures, salinities and densities of its fluid inclusions range from 56℃ to 76℃, w(NaCleq) 1.23% to 19.84%, and 0.99 g/cm3 to 1.12 g/cm3 respectively, and the compositions are given priority to CH4. The δD(H2O)V-SMOW and δ18O(H2O)V-SMOW of its metallogenic fluids vary from -93.0‰ to -48.3‰ and -10.3‰ to -5.1‰ respectively. The δ13CV-PDB and δ18OV-SMOW of its carbonate cement from ore-bearing sandstone range from -10.9‰ to -7.2‰ and 17.6‰ to 24.9‰ respectively. These characteristics imply that the metallogenic fluids were mixed fluids consisting of surface-water stemming from meteoric water and organic acid associated with coal-formed gas (CH4) originating from coal measure strata and had such characteristics as low temperature, large salinity range, medium density and multiple superimposition. The Mengqiguer uranium deposit is different from the deposit of deep oil and gas filling. The combined action of oxygen- and uranium-bearing endosmic surface-water, coal-formed gas and other reducing fluids originating from coal measure strata led to the formation of the Mengqiguer uranium deposit.
文章编号：
中图分类号：P619.14
文献标志码：
基金项目:本文得到国家973计划项目(编号:2015CB453004)、国家863计划项目(编号:2012AA061801)和铀矿地质勘查项目"铀成矿作用模拟实验研究(编号:201489)"联合资助
引用文本：
丁波,刘红旭,修晓茜,刘涛,潘澄雨,张晓,李平.2016.新疆蒙其古尔铀矿床成矿流体特征及其与铀成矿的关系[J].矿床地质,35(3):559~572DING Bo,LIU HongXu,XIU XiaoQian,LIU Tao,PAN ChengYu,ZHANG Xiao,LI Ping.2016.Metallogenic fluid characteristics in relation to uranium mineralization in Mengqiguer uranium deposit, Xinjiang[J].Mineral Deposits35(3):559~572
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