开鲁盆地位于松辽盆地西南部，是中国北方砂岩型铀矿勘查的重点地区。自钱家店铀矿床发现以来，盆地内上白垩统姚家组中相继发现了一系列具有工业价值的铀矿床，显示其勘探潜力。为查明研究区目的层砂岩的沉积物源和铀源特征，本文对开鲁盆地宝龙山地区姚家组砂岩进行了碎屑组分、全岩地球化学和碎屑锆石LA-ICP-MS定年分析。结果表明：研究区砂岩主要为岩屑砂岩，成分成熟度低，具有近物源，沉积较快的特征。样品轻稀土元素（LREE）含量为80.27×10-6～ 184.67×10-6，平均119.21×10-6；重稀土元素（HREE）的含量为11.38×10-6至23.31×10-6(平均15.02×10-6)，LREE/HREE为6.91～8.93（平均7.92），表明轻稀土富集，重稀土亏损，轻重稀土高度分馏。稀土元素球粒陨石标准化曲线具有明显的右倾及负Eu异常（δEu=0.49～0.84，平均0.57）。CIA指数（58.41～74.80）及CIW指数（74.52～95.74）指示姚家组母岩经历了中等至强烈的风化蚀变。物源主要形成于上大陆地壳活动大陆边缘环境。碎屑锆石U-Pb年龄为126～2501 Ma，具有两个主要的年龄范围：126～155 Ma和245～276 Ma，此外还有少量早古生代及古元古代的锆石。通过区域对比分析，明确了姚家组碎屑物质主要来自大兴安岭南段，少量来自燕山造山带的贡献。母岩主要为物源区广泛出露的长英质火成岩，并混合有少量变质岩组合。除了为研究区提供碎屑物质外，源区富含铀的长英质火成岩还提供了长期、稳定和良好的铀源，表明研究区的铀矿勘探潜力巨大。

The sandstone-hosted uranium deposits in the SW Songliao Basin differ from typical sandstone-hosted uranium deposits in terms of the geological features of the ore-deposits, including the geometry of the orebodies, mineral assemblage and petrography. Detailed drill core and microscopic observations, scanning electron microscopy (SEM), electron microprobe analysis (EMPA), heavy mineral concentrates, and fluid inclusion studies of the Upper Cretaceous Yaojia Formation, i. e., the uranium-bearing layer, were integrated to investigate the roles of hydrothermal fluids in the formation of these uranium deposits. We found that the kaolinite alteration is developed in the mineralized zones, but it is less common in the peripheral areas. The fluid inclusions are hydrothermal fluids with a medium-low temperature (67 to 179 degrees C) and a high salinity (5.9 wt.% to 20.1 wt.%). According to the analyses, three kinds of hydrothermal fluids, i.e., the acid fluid, the groundwater heated by the mafic magma, and the alkaline fluid rich in Ca2+ and CO32-, were identified. The fluids might have low U content, but they have participated in the formation of the uranium deposits successively. Kaolinite formed by the acid-hydrothermal fluid absorbed large amounts of uranium. Subsequently, the thermal energy from the hydrothermal fluids changed the intrastratal redox environment and increased the solubility of the uranium minerals in the fluid. The alkaline-hydrothermal fluid rich in Ca2+ and CO32- facilitated the formation of stable Ca-U(VI)-CO3 complex, which led to the enrichment of soluble uranium in solution, and final precipitation as pitchblende, brannerite and Ti-bearing uranium minerals in the uranium ores.

二连盆地在近20年已探明多个砂岩、泥岩型铀矿床,是我国重要的产铀盆地。位于二连盆地边缘西北部隆起区的卫镜岩体,是一个多期次（海西—燕山期）的复式岩体。其分布面积广（>1000km^2 ）且有多个铀矿床围绕分布。为查明卫镜岩体与盆地内铀成矿之间的关系,开展了详细地野外地质调查,采取了卫镜岩体出露地表、钻孔中揭露的岩石以及盆地内含矿目的层砂岩样品。露头观察和镜下鉴定结果表明,卫镜岩体主要为中粗粒黑云母似斑状花岗岩。其在地表已被强烈风化、剥蚀乃至夷平。含矿目的层砂岩中主要碎屑颗粒为石英、长石（斜长石与钾长石）,部分为花岗岩岩屑,它们主要来自花岗岩岩体。卫镜岩体和哈达图铀矿床目的层（赛汉组）砂岩样品稀土元素及其参数对比表明,含矿层砂岩物质成分来自于卫镜岩体。卫镜岩体与赛汉组砂岩样品Pb同位素分析结果表明,卫镜岩体原始铀含量（U 0 ）较高,平均达15.17×10^–6 ,丢失的铀含量平均达到–45.47%。赛汉组氧化带砂岩中铀明显丢失,平均铀的丢失率为–41.42%,而还原带砂岩中铀多为获得,平均铀获得率达66.80%。由此可知,目的层铀矿化中铀的来源有2方面:一是富含铀的卫镜岩体,二是含矿目的层砂岩（其物源来自卫镜岩体）本身。磷灰石裂变径迹模拟结果揭示,包括卫镜岩体在内的二连盆地西部隆起区快速抬升始于晚白垩世,止于始新世（76.7～53.8Ma）,这一结果与盆地中砂岩、泥岩型铀矿化时代基本一致。因此,抬升作用诱发了二连盆地外生铀矿床的形成。

二连盆地在近20年已探明多个砂岩、泥岩型铀矿床,是我国重要的产铀盆地。位于二连盆地边缘西北部隆起区的卫境岩体,是一个多期次(海西—燕山期)的复式岩体。其分布面积广(>1000km~2)且有多个铀矿床围绕分布。为查明卫境岩体与盆地内

松辽盆地西南缘近年来铀找矿获得重要突破,预示着盆地蕴藏丰富的铀资源。而铀的成矿机理有待查明,尤其是矿床中广泛发育的辉绿岩,是否对成矿有改造作用,辉绿岩、反转构造及铀元素聚集之间的关系目前尚不十分清楚,制约了进一步找矿的思

Apatite fission track (AFT) sampled from Helan Mountain, of the western Ordos Basin, North China shows that the study area located in the western part of the North China Craton (NCC) has undergone four-stage exhumation since Mesozoic time, that is, Late Jurassic to Early Cretaceous, Late Cretaceous, Early Cenozoic, and post-late Miocene. Helan Mountain had slowly uplifted and eroded from the Late Jurassic to the beginning of the Cenozoic. The intensive deformation within NCC is attributable dynamically to the gently angular subduction of the Pacific Plate under the Eurasian Plate (EP). Helan Mountain has undergone sinistral strike-slipping with a 60-km maximum displacement caused by the collision of the southeast margin of EP during the Late Cretaceous. The Early Cenozoic tectonic event in the study area is respondent to collision between the Indian Plate and Eurasian Plate, whereas, the post-late Miocene event is likely related to the eastward extension of Tibet Plateau. Based on the available AFT ages, the partial annealing zone for the palaeo-Helan Mountain is ascertained to elevation similar to 1,200 m to similar to 2,100 m. The tectonic events occurring from Mesozoic to Cenozoic in Helan Mountain is directly related to the plate margin tectonism and representative for the intracontinental deformation of Eurasian Plate convergence. The sandstone-type uranium deposits in the western margin thrust belt of Ordos Basin are related to the Late Jurassic to Early Cretaceous and Late Cretaceous exhumation events. Immediately after the host rock, the Zhiluo Formation sedimentation during the Middle Jurassic, the Late Jurassic similar to Late Cretaceous exhumations resulted in north-south-trending anticlines, synclines, and thrust faults; meanwhile, the Zhiluo Formation was uplifted to the surface and infiltrated by uranium-bearing oxidized fluids originated from the Helan Mountain. Uranium deposits were formed in both east and west limbs of folds. Finally, uranium mineralization ceased since the Cenozoic because the Yinchuan and Hetao faulted grabens have separated the Helan Mountain provenance from the western margin thrust belt.

开鲁盆地位于松辽盆地西南部,是中国北方砂岩型铀矿勘查的重点地区,自钱家店铀矿床发现以来,盆地内上白垩统姚家组目的层中相继发现了一些具有工业价值的铀矿床。为查明该层位中黄铁矿成因及其形成机制,探讨其与铀矿化之间的关系,本研究对含矿层砂岩中黄铁矿与铀矿物矿物学特征、黄铁矿S同位素开展细致研究。研究表明:（1）开鲁盆地姚家组砂岩中铀主要以独立铀矿物及吸附铀形式存在,独立铀矿物以沥青铀矿为主,含少量的钛铀矿及部分铀石,多数沿黄铁矿周边生长。吸附态的铀与黏土矿物密切相关。（2）姚家组砂岩中黄铁矿主要以草莓状、胶状及粒状产出,多与沥青铀矿共生,其中黄铁矿S同位素(d34S=–55.6‰～23.2‰),平均值–20.87‰,变化范围很大,说明硫的分馏程度较高,硫的来源范围较广。（3）分析表明黄铁矿具有细菌硫酸盐还原作用及热化学硫酸盐还原作用两种成因,并探讨了这2种成因黄铁矿的形成机制。综合前人研究,结合研究区成矿地质背景,认为黄铁矿为铀成矿作用提供了发生还原反应所需要的还原剂,且黄铁矿及铀矿物的形成与区内热流体存在紧密联系。

"向地球深部进军是我们必须解决的战略科学问题"是习近平总书记提出的重要论断,也是国家对地学工作者提出的新要求。深部地质作用地球行星作为载体在太阳恒星系统及其更大尺度空间综合作用的结果。从短周期的月球-地球作用的潮汐,到地球-太阳作用的四季更替,再到较大尺度的冰期-间冰期更替,乃至更大周期,无一不影响到地球自身,诸如膨胀-收缩,海平面升降,活火山爆发与宁静,成灾-成矿/成藏,生存环境的毁灭与再造,深刻地影响着我们地球家园的生态环境。战略性关键矿产多受控于深部地质作用。金刚石产在金伯利岩-钾镁煌斑岩-橄榄玄武岩中,新能源矿产铀矿产于深源断裂控制的火山岩或砂岩中,锂-铷-铯和铌-钽-锆-铪等稀有金属多产于深源流体控制的伟晶岩中,金、银、铂族元素、钴、铼等稀贵金属多受控于深源流体,稀土元素多产于深源的碳酸岩-碱性杂岩中。这些矿产大多数对于新兴产业是必不可少的原料。同时,深部地质作用及其浅部产物是人类认识地核-地幔物质组成的窗口。战略性关键矿产历史性地将深部地质作用研究的重任交给地学工作者。近年来,多家科研单位、高等院校和地勘单位对深部地质作用及相关的战略性关键矿产开展了地质调查和科学研究,在金伯利岩、钾镁煌斑岩、玄武岩等深部地质作用和金刚石、贵金属、铀矿、稀土稀有稀散矿产等成矿作用等方面取得了一系列新进展。为了更好地推动深部地质作用和战略性关键矿产相关的学术研究和应用转化应用,服务国家需求,《地球学报》组织了"深部地质作用及战略性关键矿产"专辑,服务于深部探测和战略性关键矿产（金刚石、铀矿、稀土-稀有-稀散-稀贵金属）相关研究和勘查工作的专家、学者。

长期以来,盆地中砂岩型铀矿的成矿与找矿仅关注表生低温氧化作用形成的铀矿化,忽视了复杂地质演化过程中多阶段、多模式的成矿作用。中国北方东部盆地自晚中生代以来经历了伸展-挤压-伸展的多阶段演化过程,铀成矿作用必将对这种多阶段构造演化密切响应。本研究通过中国北方东部巴音戈壁盆地塔木素矿床、二连盆地哈达图矿床、松辽盆地南部钱家店—白兴吐矿床等大型、巨型砂岩型铀矿床的精细解剖,分析矿床中矿体的变化特征和含矿目的层流体-岩石相互作用的标记,探索矿床形成的构造、沉积、铀源、还原剂等成矿控制因素,尤其是（古）太平洋板块在不同阶段、以不同的方式俯冲给研究区盆地带来的深刻影响。以区域构造演化为主线,确定早白垩世至晚白垩世早期,盆地在古太平洋板块高角度俯冲下发生伸展裂陷和拗陷作用,厘定砂岩型铀矿含矿目的层巴音戈壁组（K1b）辫状三角洲、赛汉组（K1bs）辫状河、姚家组（K2y）辫状河及曲流河等沉积环境。晚白垩世晚期,由于古太平洋板块的俯冲由高角度转变为低角度,盆地首次出现由伸展裂陷转变为挤压抬升的正反转演化,表生含铀含氧流体与砂岩相互作用,形成以赤铁矿、褐铁矿化等氧化作用为标志的早期氧化带型"卷状"铀矿化。始新世以来,太平洋板块的俯冲再次由低角度转变为高角度,盆地构造由挤压抬升转变为伸展张裂的负反转演化,导致正断层与基性岩浆活动,并伴随热流体与含矿目的层砂岩相互作用,出现大量的Fe、Mg碳酸盐、热液硫化物、绿泥石、绢云母等蚀变组合,铀矿体形态由原来的"卷状"变成了"透镜状"、"囊状"、"板状",并伴有高温钛铀矿的出现,形成晚期热液叠加铀矿化。两个成矿时期和两种不同方式的成矿作用被本文凝练为"双阶段双模式"铀成矿。结果表明,针对在中国北方东部提出的"双阶段双模式"铀成矿作用模型,下一步找矿上既要关注早期的氧化带型铀矿化,更要注重晚期的热流体叠加改造型铀矿化。