盆山耦合机制驱动下的库车坳陷铀成矿作用响应  

Response of Uranium Mineralization in Kuqa Depression Driven by Basin⁃Mountain Coupling Mechanism

作　　者：吴立群[1,2] 焦养泉[1,2] 王国荣[3] 王强强[3] 荣辉[1,2] 阿种明[3] 张帆[1,2] 鲁克改 陶振鹏[4] 孙潇 向尧[1,2] Wu Liqun;Jiao Yangquan;Wang Guorong;Wang Qiangqiang;Rong Hui;A Zhongming;Zhang Fan;Lu Kegai;Tao Zhenpeng;Sun Xiao;Xiang Yao(School of Earth Resources,China University of Geosciences,Wuhan 430074,China;Key Laboratory of Tectonics and Petroleum Resources,Ministry of Education,China University of Geosciences,Wuhan 430074,China;Geologic Party No.216,CNNC,Urumqi 830011,China;School of Architectural Engineering,Huanggang Normal University,Huanggang 438000,China)

机构地区：[1]中国地质大学资源学院,湖北武汉430074 [2]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 [3]核工业二一六大队,新疆乌鲁木齐830011 [4]黄冈师范学院建筑工程学院,湖北黄冈438000

出　　处：《地球科学》2022年第9期3174-3191,共18页Earth Science

基　　金：核工业二一六大队地勘费项目(Nos.201907,201907‐4);国家重点研发计划项目(No.2018YFC0604202).

摘　　要：库车坳陷周缘的铀矿化非常活跃,蕴藏于上新统库车组下段的砂岩型铀矿的控矿要素、成矿机理、成矿规律,特别是远景选区是近年来铀矿地质学家关注的重点.笔者充分依据区域地质资料、野外地质调查和勘查钻孔资料,通过综合分析,试图在构造‒沉积‒地形地貌的盆山耦合机制中,遵循砂岩型铀矿的普遍成矿机理、按照由源到汇的研究思路,剖析砂岩型铀矿形成发育的关键控矿要素、时空配置关系,从铀成矿系统分析的角度揭示库车组关键控矿要素的协同控矿机理,以期为铀矿勘查提供战略服务.主要认识有:新生代南天山造山带的大规模陆内逆冲推覆作用既控制了库车组含铀岩系的充填演化过程,也制约了库车组下段铀成矿的基本格局和成矿作用过程,盆山耦合机制是驱动砂岩型铀矿形成发育的原始驱动力.南天山造山带岩浆岩分布规模虽然有限,但在托木尔峰一带存在富铀花岗岩.充分发育的地表水流域系统,一方面能够携带造山带的碎屑物堆积于库车坳陷,从而分阶段形成系列的大型物源‒沉积朵体,造就了潜在的含铀岩系和优质的铀储层.另一方面,穿越造山带富铀花岗岩的流域系统,不仅通过物理搬运为铀储层提供了原始微量铀的积累,而且通过衍生的地下含矿流体系统促进了区域层间氧化带的发育以及成矿所需的溶解铀质.在库车坳陷,近东西向展布的构造行迹限定了含矿流场和层间氧化带的发育空间(拜城凹陷),铀矿化集中发育于区域层间氧化带前锋线附近(特别是南部“阻水面”一侧).在拜城凹陷南部边缘,随着具有同沉积生长性质的秋里塔格构造带的不断隆升,区域的含矿流场和层间氧化带被迫向北迁移并发生“左旋”,从而造就了包括日达里克铀矿床在内的“新”“老”两个铀成矿系统.Uranium mineralization around Kuqa depression is very active.The ore-controlling factors,metallogenic mechanism and metallogenic law,especially the prospective selection,of sandstone‐type uranium deposits in the lower member of Pliocene Kuqa Formation have become the focus of uranium geologists in recent years.Based on the regional geological data,field geological survey and exploration drilling data,through comprehensive analysis,the author attempts to analyze the key ore-controlling factors and spatial and temporal collocation relationship of the formation and development of sandstone‐type uranium deposits in the context of basin‐mountain coupling mechanism(tectonics&sediments&geomorphology),following the general metallogenic mechanism of sandstone‐type uranium deposits and the research idea from source to sink.From the perspective of uranium metallogenic system analysis,the cooperative ore control mechanism of key ore‐controlling elements of Kuqa Formation is revealed in order to provide strategic services for uranium exploration.It is found that large-scale intracontinental thrust nappe of the Cenozoic South Tianshan orogenic belt not only controls the filling evolution process of the uranium bearing rock series of the Kuqa Formation,but also restricts the basic pattern and metallogenic process of uranium mineralization in the lower member of the Kuqa Formation.The basin‐mountain coupling mechanism is the original force driving the formation and development of sandstone‐type uranium deposits.Although the distribution scale of magmatic rocks in the South Tianshan orogen is limited,Urich granites exist in the Tomur peak area.The fully developed surface water drainage system,on the one hand,can carry the debris of the orogenic belt to accumulate in the Kuqa depression,thus forming a series of large provenance-sedimentary lobes in stages,creating potential uranium bearing rock series and high-quality uranium reservoir.On the other hand,the drainage system crossing the U-rich granites in the orogenic

关 键 词：砂岩型铀矿 控矿要素 铀成矿系统 盆山耦合 库车组下段 库车坳陷 矿床学 

分 类 号：P619.14[天文地球—矿床学]