塔里木盆地萨瓦甫齐铀矿床中黄铁矿成因特征及其对铀成矿作用的指示  

Discussion of the genetic relationship between pyrite and uranium mineralization in Sawafuqi sandstone-type uranium deposits of Tarim basin

作　　者：武勇 秦明宽 许强[1,2,3] 郭强 何升 蔡叶蕾[1,2,3] 林燕 WU Yong;QIN Mingkuan;XU Qiang;GUO Qiang;HE Sheng;CAI Yelei;LIN Yan(National Key Laboratory of Uranium Resources Exploration-Mining and Nuclear Remote Sensing,Beijing 100029,China;Beijing Research Institute of Uranium Geology,Beijing 100029,China;CNNC Key Laboratory of Uranium Resources Exploration and Evaluation Technology,Beijing 100029,China)

机构地区：[1]铀资源探采与核遥感全国重点实验室,北京100029 [2]核工业北京地质研究院,北京100029 [3]中核集团铀资源勘查与评价技术重点实验室,北京100029

出　　处：《世界核地质科学》2024年第6期1106-1117,共12页World Nuclear Geoscience

基　　金：核技术研发科研项目(编号:测HTLM2101-08)资助。

摘　　要：塔里木盆地北端的萨瓦甫齐砂岩型铀矿床是该地区侏罗系中重要的大型铀矿床,矿石显示黄铁矿与铀矿之间成因关系密切。本研究着重分析铀矿床中含矿层砂岩中黄铁矿、铀矿石的矿物组合及微观形态特征,黄铁矿的硫同位素组成,探讨黄铁矿的成因及其与铀成矿过程的联系。研究结果表明:1)矿石中黄铁矿与沥青铀矿、铀石和富铀的铁钛氧化物共生关系明显,铀矿物大多产在黄铁矿边缘;2)矿石中黄铁矿普遍以粒状和胶状出现,其硫同位素数值(δ^(34)S_(v-CDT))变化从-56.24‰至-11.44‰,平均为-25.79‰,较大变化幅度揭示它们具有多成因性;3)黄铁矿与沥青铀矿、有机质以及碎屑矿物共存,暗示黄铁矿的生成有细菌硫酸盐还原和有机质参与,推断黄铁矿在铀矿化过程中起到还原作用,提供必需的还原介质,黄铁矿与铀矿物的形成过程与研究区的含煤地层有着一定的成因联系。Sawafuqi sandstone-type uranium deposit is the main large uranium deposit in the Jurassic of northern Tarim basin,and in the ores presented the close relation of pyrite and uranium minerals.This study focused on the mineral association and microscopic morphological characteristics of the uranium-bearing layers in the sandstone,analyzed the sulfur isotope composition of pyrite to determine its origin and its relation to the uranium mineralization.The results showed that:1)pyrite was closely associated with uraninite,coffinite,and uranium-rich titanium-iron oxide in the ore body,and uranium minerals are mostly found on the edges of pyrite;2)pyrite was commonly found in the form of grains and colloidal particles in the ore body,sulfur isotope values of the pyrite ranged widley from-56.24‰ to-11.44‰ with an average of-25.79‰ indicating its multiple origins;3)the pyrite was coexisted with uraninite,organic matter and clastic minerals which suggest the formation of pyrite was involved with the bacterial reduction and organic matter participation.Therefore the pyrite played a reducing role in uranium mineralization,which resulted in the closely relation of pyrite and uranium minerals in the coal-bearing strata in the study area.

关 键 词：萨瓦甫齐铀矿床 黄铁矿 硫同位素 砂岩型铀矿 塔里木盆地 

分 类 号：P597.2[天文地球—地球化学]