钱家店铀矿床层间氧化带中铁钛氧化物的赋存状态及其对铀成矿的响应  

Occurrence State of Fe-Ti Oxides and Its Response to Uranium Mineralization Process in Interlayer Oxidation Zone of Qianjiadian Uranium Deposit

作　　者：张宇辰 荣辉[1] 焦养泉[1] 曹民强 李清春 郭亮亮 郭长琪 周明旺[3] Zhang Yuchen;Rong Hui;Jiao Yangquan;Cao Minqiang;Li Qingchun;Guo Liangliang;Guo Changqi;Zhou Mingwang(Key Laboratory of Tectonics and Petroleum Resources,Ministry of Education,China University of Geosciences,Wuhan 430074,China;Tongliao Uranium Industry Branch of Liaohe Petroleum Exploration Bureau Co.,Ltd.,Panjin 124010,China;Liaohe Oilfield Exploration and Development Research lnstitute,Panjin 124010,China)

机构地区：[1]中国地质大学构造与油气资源教育部重点实验室,湖北武汉430074 [2]辽河石油勘探局有限公司通辽铀业分公司,辽宁盘锦124010 [3]辽河油田勘探开发研究院,辽宁盘锦124010

出　　处：《地球科学》2024年第6期2024-2043,共20页Earth Science

基　　金：国家重点研发计划项目(No.2018YFC0604202);国家青年科学基金项目(No.41502105);中国地质大学(武汉)学科杰出人才基金项目(No.102-162301192664)。

摘　　要：铁钛氧化物对氧化-还原环境的变化极为敏感,是砂岩型铀矿成矿作用研究极为重要的标型矿物.然而,国内外对铁钛氧化物在砂岩型铀矿层间氧化带不同分带中形貌、含量及组合特征的研究却缺少量化数据的约束.鉴于此,本文以松辽盆地钱家店铀矿床层间氧化带中铁钛氧化物为研究对象,通过偏光显微镜、扫描电镜、电子探针等手段,识别出6种铁钛氧化物:钛铁矿、钛赤铁矿、钛磁铁矿、白钛石、金红石和锐钛矿,其中完全氧化亚带和部分氧化亚带以钛赤铁矿、钛磁铁矿为主,微弱氧化亚带以金红石、锐钛矿、钛磁铁矿为主,过渡带以白钛石、锐钛矿为主,还原带以金红石、锐钛矿、钛铁矿与白钛石为主.从钛铁矿氧化物与铀矿物的产出关系来看,锐钛矿、白钛石与金红石与铀成矿关系最为密切.根据各个分带中铁钛氧化物之间的穿插包裹关系,识别出7种蚀变序列,其中,完全氧化亚带、部分氧化亚带与微弱氧化亚带中以钛铁矿→钛磁铁矿→磁铁矿、钛铁矿→钛赤铁矿、白钛石→钛磁铁矿→磁铁矿以及白钛石→钛赤铁矿4种蚀变序列为主,记录了铀矿床的大规模层间氧化事件;过渡带中主要表现为白钛石→锐钛矿和金红石→锐钛矿两种蚀变序列,体现了晚期成矿阶段该矿床受到低温热液流体改造事件;还原带中主要表现为钛铁矿→白钛石的蚀变序列,反映了成岩时期弱酸性-弱碱性的环境.研究成果为铁钛氧化物作为标型矿物研究砂岩型铀矿床层间氧化带精细分带及铀成矿作用过程奠定了基础.Fe-Ti oxides are extremely sensitive to changes in the redox environment and are extremely important indicator minerals for studying the mineralization of sandstone-type uranium deposits.However,there are few quantitative data constraints on morphology,contents and compositions of Fe-Ti oxides in the interlayer oxidation zone of sandstone-type uranium deposits.Therefore,in this study it focuses on illustrating Fe-Ti oxides in the interlayer oxidation zone of Qianjiadian uranium deposit in Songliao basin.Six types of Fe-Ti oxides including ilmenite,titanohematite,titanomagnetite,leucoxene,rutile and anatase have been identified by polarizing microscope,SEM and electron probe microanalyzer.The titanohematite and titanomagnetite mainly occur in the strong oxidised subzone and weak oxidised subzone;the leucoxene,anatase and titanium magnetite are mainly distributed in the faint oxidised subzone;the leucoxene and anatase are primarily formed in the transition zone,and the rutile,ilmenite and leucoxene are frequently found in the reduction zone.Seven alteration sequences are identified according to the interspersed wrapping relationship between Fe-Ti oxides in each zone.Four alteration sequences composed of ilmenite→titanomagnetite→magnetite,ilmenite→titanohematite,leucoxene→titanomagnetite→magnetite and leucoxene→titanohematite are mainly found in the strong oxidised subzone,weak oxidised subzone and faint oxidised subzone,and these sequences record a large-scale interlayer oxidation event.Two alteration sequences including leucoxene→anatase and rutile→anatase primarily occur in the transition zone,these sequences reveal that the deposit was transformed by low-temperature hydrothermal fluids.The last alteration sequence is ilmenite→anatase which mainly occur in the reduction zone,and this sequence reflects a weakly acidicweakly alkaline environment during diagenesis.The research provides a foundation for the studying Fe-Ti oxides as indicator minerals to study fine zoning of interlayer oxidation zone

关 键 词：铁钛氧化物 砂岩型铀矿 层间氧化带 姚家组 松辽盆地 铀储层 沉积学 矿床 

分 类 号：P611.2[天文地球—矿床学]