准噶尔盆地西北缘下白垩统吐谷鲁群沉积特征及铀矿找矿方向  

Sedimentary characteristics of Lower Cretaceous in Wuerhe-Huanghuagou area,northwestern margin of Junggar Basin

作　　者：冀华丽 何中波[1,2] 钟军 陈虹[3] 朱斌 吴玉[1,2] 东前 耿英英[1,2] JI Huali;HE Zhongbo;ZHONG Jun;CHEN Hong;ZHU Bin;WU Yu;DONG Qian;GENG Yingying(Beijing Research Institute of Uranium Geology,Beijing,100029;CNNC Key Laboratory of Uranium Resources Exploration and Evaluation Techniques,Beijing,100029;Geologic Party No.216,CNNC,Urumqi,830011)

机构地区：[1]核工业北京地质研究院,北京100029 [2]中核集团铀资源勘查与评价技术重点实验室,北京100029 [3]新疆核工业二一六大队,乌鲁木齐830011

出　　处：《地质论评》2024年第4期1267-1290,共24页Geological Review

基　　金：中核集团集中研发项目“砂岩型铀矿多重耦合地质成矿作用与时空定位”专项(编号:中核科发2021-143号);中核集团青年英才“菁英”项目(编号:地QNYC2201)的成果。

摘　　要：笔者等通过对准噶尔盆地西北缘乌尔禾—黄花沟地区的露头和钻孔岩芯、钻测井综合分析,结合镜下观察,对下白垩统吐谷鲁群主要岩石学特征、地层结构、沉积相类型及其展布特征进行了综合分析。以砂岩型铀矿成矿理论为指导,从沉积学角度,探讨了研究区下白垩统吐谷鲁群有利成矿砂体的类型及分布情况。结果表明:(1)下白垩统吐谷鲁a亚群岩石类型主要为长石岩屑砂岩和岩屑长石砂岩,吐谷鲁b、c和d亚群则以长石砂岩和长石岩屑砂岩为主;(2)下白垩统吐谷鲁群发育冲积扇、辫状河、三角洲和湖泊等4种沉积相类型,以德伦山为界,乌尔禾—夏子街一带发育远源弱流的浅水三角洲相,物源来自北西的雪米斯坦,而德伦山—黄花沟一带以发育高能量的辫状河沉积为主,物源应来自盆地北部;(3)下白垩统有利找矿层位为吐谷鲁a+b亚群的原生灰—灰绿色粗碎屑建造。乌尔禾—油砂山一带的三角洲平原亚相分支河道是重要的找矿方向;夏子街一带广泛发育的三角洲前缘水下分流河道和席状砂厚大砂体具备形成一定规模砂岩型铀矿的能力;黄花沟一带在吐谷鲁a+b时期发育宽广且具有较大规模的辫状河砂体是寻找层间氧化和潜水氧化的有利区域。Objectives:By combining outcrop,core,and logging,the sedimentary characteristics and sand body development characteristics of the Lower Cretaceous were finely characterized,and the exploration direction of sandstone type uranium deposits in the Wuerhe-Huanghuagou area was explored.Methods:Based on the comprehensive analysis of outcrops,drilling cores,drilling and logging in the Wuerhe-Huanghuagou area on the northwestern margin of the Junggar Basin,combined with microscopic observation,the main petrological characteristics,stratigraphic structure,sedimentary facies types and distribution characteristics of the Lower Cretaceous Tugulu Group were comprehensively analyzed.Guided by the metallogenic theory of sandstone-type uranium deposits,the types and distribution of favorable ore-forming sand bodies in the Lower Cretaceous Tugulu Group in the study area were discussed from the perspective of sedimentology.Results:①The rock types of the Lower Cretaceous Tugulu-a Subgroup in the study area are mainly feldspar lithic sandstone and lithic feldspar sandstone,while the Tugulu-b,Tugulu-c and Tugulu-d subgroups are mainly feldspar sandstone and feldspar lithic sandstone.②There are four types of sedimentary facies in the Lower Cretaceous Tugulu Group in the study area,which are alluvial fan,braided river,delta and lake,its provenance is from the northwest of Semistan Mountain.With the Delunshan as the boundary,the Wuerhe-Xiazijie area is dominated by shallow-water delta deposits with far-source weak current,while the Delunshan-Huanghuagou area is dominated by high-energy braided river deposits,its provenance should come from the northern part of the basin.③The favorable prospecting horizon of the Lower Cretaceous is the primary gray-gray green coarse clastic formation of the Tugulu-a+Tugulu-b Subgroup.Conclusions:The branch channel of delta plain subfacies in Wuerhe-Youshashan area is an important prospecting direction.The underwater distributary channel of delta front and the thick sand body of sheet sand widely de

关 键 词：沉积特征 沉积相 砂岩型铀矿 下白垩统吐谷鲁群 乌尔禾—黄花沟地区 准噶尔盆地 

分 类 号：P619.14[天文地球—矿床学]