| 中新生代构造演化对砂岩型铀矿床成矿的制约——来自伊盟隆起磷灰石裂变径迹的证据 |
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| 引用本文： | 王少轶,程银行,吏成辉,李艳锋,张天福,程先钰,杨君.中新生代构造演化对砂岩型铀矿床成矿的制约——来自伊盟隆起磷灰石裂变径迹的证据[J].大地构造与成矿学,2020(4):682-696. |
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| 作者姓名： | 王少轶 程银行 吏成辉 李艳锋 张天福 程先钰 杨君 |
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| 作者单位： | 中国地质调查局天津地质调查中心;中国地质调查局铀矿地质重点实验室;中钢集团天津地质研究院有限公司 |
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| 基金项目： | 国家重点研发计划项目(2018YFC0604200);中国地质调查局项目(DD20190813);国家重点基础研究发展计划项目(2015CB453000);国际地球科学计划(IGCP675)联合资助。 |
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| 摘 要： | 砂岩型铀矿床具有水成的、动态的、开放的特征,其形成及后期改造与盆地构造隆升关系密切。本文在热年代学研究的基础上,查明了伊盟隆起中生代以来具有四期构造抬升事件:150~126 Ma、110~100 Ma、100~75 Ma、50~35 Ma,且四期抬升事件隆升强度逐渐降低。其中第一期(150~126 Ma)抬升事件以南北向的差异性抬升过程为特征,第二期(110~100 Ma)抬升事件表现为东隆西降的掀斜过程,第三、四期(100~75 Ma和50~35 Ma)抬升事件表现为整体抬升。通过与伊盟隆起周缘地区对比,发现伊盟隆起与贺兰山地区作为统一的整体共同经历了四期抬升事件,30 Ma以来贺兰山快速隆升与鄂尔多斯盆地分离,并伴随银川盆地形成。在系统统计研究区内砂岩型铀矿成矿年代学成果基础上,总结出伊盟隆起内三期砂岩型铀矿床成矿过程:第一期为早白垩世128.2±4.2 Ma^120±11 Ma;第二期为晚白垩世90±5.3 Ma^71±8 Ma;第三期为古近纪古新世?新近纪中新世54.6±1.8 Ma^20±2 Ma。第一期成矿作用发生于第一期和第二期构造抬升转换期,第二期和第三期成矿作用分别与第三期和第四期抬升作用密切相关,构造隆升强度较大并不利于砂岩型铀矿床的沉淀和矿体就位。30 Ma以来发育于伊盟隆起的砂岩型铀矿床进入成矿后演化阶段。
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| 关 键 词： | 鄂尔多斯盆地 裂变径迹年代学 中新生代构造演化 砂岩型铀矿 |
Tectonic Evolution and its Controls on the Sandstone-type Uranium Mineralization in the Yimeng Uplift:Constraints from Apatite Fission Track Thermochronology |
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| WANG Shaoyi,CHENG Yinhang,LI Chenghui,LI Yanfeng,ZHANG Tianfu,CHENG Xianyu,YANG Jun.Tectonic Evolution and its Controls on the Sandstone-type Uranium Mineralization in the Yimeng Uplift:Constraints from Apatite Fission Track Thermochronology[J].Geotectonica et Metallogenia,2020(4):682-696. |
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| Authors: | WANG Shaoyi CHENG Yinhang LI Chenghui LI Yanfeng ZHANG Tianfu CHENG Xianyu YANG Jun |
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| Institution: | (Tianjin Center,China Geological Survey,Tianjin 300170,China;Key Laboratory of Uranium Geology,China Geological Survey,Tianjin 300170,China;Sinosteel Tianjin Geological Academy Co.,Ltd.,Tianjin 300181,China) |
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| Abstract: | Sandstone-type uranium deposits are characterized by hydrous,dynamic and open.The formation and the later transformation of the sandstone type uranium deposits are closely related to structural uplifts of the basins.Four tectonic uplift events since Mesozoic can be distinguished based on the geochronological study of the Yimeng Uplift,i.e.,150–126 Ma,110–100 Ma,100–75 Ma,and 50–35 Ma.The first uplift event is characterized by a North-South differential uplift.The second stage uplift is the lifting process of the East Longxi Depression,the third and fourth stages are overall uplifting,and the intensity of uplift diminished in the fourth stage.Compared with the peripheral area of the Yimeng Uplift,it can be inferred that the Yimeng uplift and the Helan Mountain area as a whole experienced four uplift events.Since 30 Ma,the rapid uplift of the Helan Mountain separated it from the Ordos Basin,and accompanied by the formation of the Yinchuan Basin.The geochronological results of sandstone type uranium deposits in the area show that there are three periods of sandstone type uranium mineralization in the Yimeng Uplift,i.e.,the Early Cretaceous(128.2±4.2 Ma–120±11 Ma),the Late Cretaceous(90±5.3 Ma–71±8 Ma),and the Paleocene Neogene Miocene(54.6±1.8 Ma–20±2 Ma).The first stage of mineralization occurred in the first and the second stages of the structural uplift,and the second and third stages of mineralization are closely related to the third and fourth stages of uplift,respectively.The strong tectonic uplift is not necessarily conducive to the deposition of sandstone type uranium deposits and the emplacement of ore bodies.The sandstone-type uranium mineralization in the Yimeng Uplift ended at ca.30 Ma. |
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| Keywords: | the Ordos Basin fission track chronology Meso-Cenozoic tectonic evolution sandstone type uranium deposit |
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