排序方式： 共有36条查询结果，搜索用时 15 毫秒
1.
JIAO Yangquan WU Liqun RONG Hui PENG Yunbiao MIAO Aisheng WANG Xiaoming 《《地质学报》英文版》2016,90(6):2117-2132
Outcrop and drill hole data show that the Jurassic coal measures in the northeastern Ordos Basin are composed mainly of the Yan'an Formation and the lowstand system tract of the Zhiluo Formation,and there is a regional unconformity between them. The Dongsheng uranium deposit is associated with the Jurassic coal measures. Research data indicate that the Jurassic coal measures in the study area have a certain hydrocarbon-generating capacity,although the metamorphic grade is low(Ro=0.40%–0.58%). In the Dongsheng region alone,the accumulative amount of generated coalbed methane(CBM) is about 2028.29 × 108 –2218.72 × 108 m~3; the residual amount is about 50.92 × 108 m~3,and the lost amount is about 1977 × 108 m~3. Analysis of the burial history of the host rocks and the evolutionary history of the Dongsheng uranium deposit suggests that the Jurassic coal measures generated hydrocarbon mainly from Middle Jurassic to Early Crataceous,which is the main mineralization phase of the Dongsheng uranium deposit. By the Late Cretaceous,a mass of CBM dissipated due to the strong tectonic uplift,and the Dongsheng uranium deposit stepped into the preservation phase. Therefore,the low-mature hydrocarbon-containing fluid in the Jurassic coal measures not only served as a reducing agent for the formation of sandstone-type uranium deposits,but also rendered the second reduction of paleo-interlayer oxidation zone and become the primary reducing agent for ore conservation. Regional strata correlation reveals that the sandstone-type uranium reservoir at the bottom of the Zhiluo Formation is in contact with the underlying industrial coal seams in the Yan'an Formation through incision or in the form of an unconformity surface. In the Dongsheng region with poorly developed fault systems,the unconformity surface and scour surface served as the main migration pathways for low-mature hydrocarbon-containing fluid migrating to the uranium reservoir. 相似文献
2.
The Bayingobi basin is the Mesozoic-Cenozoic basin in North China in which the Tamusu uranium deposit is located.The ore-target layer of the deposit is the Lower Cretaceous Bayingobi Formation,which developed as a fan deltashallow lacustrine deposit.The distributary channel sand body of the fan delta plain and the underwater distributary channel sand body of the fan delta front formed a favorable uranium reservoir,so the study of sequence stratigraphy is extremely important to understanding the genesis of uranium deposits.On the basis of field investigation and a large number of borehole logs,the high resolution sequence stratigraphy of the Lower Cretaceous is divided and the system tracts of different periods are established.The relationship between deposition,interlayer oxidation and uranium enrichment is discussed.The Lower Cretaceous Bayingobi Formation can be divided into two fourth-order sequences(Sq1 and Sq2).The lower member of the Bayingobi Formation is referred to as Sq1,which is composed of a falling-stage system tract(FSST)on top.On the other hand,the upper member of the Bayingobi Formation is referred to as Sq2,which is composed of a lowstand system tract(LST),transgressive system tract(TST)and highstand system tract(HST).The lowstand system tract forms a favorable stratigraphic structure(mud-sand-mud formation)with the lacustrine mudstone of the overlying transgressive system tract,that is conducive for the migration of uranium-bearing oxygen water.The organic matter and pyrite in the fan delta sand body,as well as the dark mudstone in the distributary bay,provided a reducing medium for uranium mineralization.The ore body mainly occurs in the distributary channel,underwater distributary channel or the mouth bar of the fan delta.As a result of the moderate thickness,high permeability,favorable barrier and rich reducing medium,the rich ore body mainly occurs in the underwater distributary channel and mouth bar sand body of the delta front.Based on study of the sequence stratigraphy,the model of the sequence,sedimentation and mineralization of the uranium deposit is established,which enriches uranium metallogenic theory and provides a reference for exploration of the same type of uranium deposits. 相似文献
3.
巴音戈壁盆塔木素地区砂岩型铀矿目的层普遍固结,矿体多层但连续性差,分布不规律,后生改造特征明显。本文通过野外露头调查、岩芯观察和微观分析,发现该地区普遍发育穿层脉状石膏或方解石、热液金属硫化物矿物、矿物重结晶与新生胶结物等,出现硫酸盐-金属硫化物共生矿物和S同位素分馏,指示存在后生热流体活动。通过对矿体、矿石特征及铀矿物成因的分析,初步认为热改造对成矿控制主要发生在层间氧化作用后期,温度升高造成碳酸钙和硫酸钙沉淀、重结晶,破坏含矿溶液中碳酸铀酰络合物的平衡,造成U的沉淀,促使铀矿化进一步富集。 相似文献
4.
5.
经过近年来的区域评价工作,在内蒙古二连盆地那仁地区赛汉组上段发现了铀矿化信息,但由于工作程度较低,铀成矿条件分析及远景预测明显不足。通过对钻孔、地震等资料的综合整理,结合系统取样、分析测试结果,对那仁地区铀源、构造、地层、沉积相、氧化-还原及古气候条件进行了全面分析。研究认为该区铀源充足,在温暖半湿润—干热气候转变期,蚀源区大量的铀被活化、迁移;晚白垩世—新生代的构造活动提供了适宜氧化带发育的斜坡带及深部还原流体上逸通道;赛汉组上段一亚段辫状河三角洲砂体规模大,具备稳定的泥-砂-泥结构和有利的氧化-还原条件,是铀矿形成的理想空间。在铀成矿条件最佳部位预测Ⅰ级远景区1片,有望落实为新的铀矿床。 相似文献
6.
7.
通过研究努和廷铀矿床地质特征、成矿作用及地球化学特征,认为努和廷矿床为同生沉积后生改造型铀矿床。晚白垩世二连期湖泊发育区控制了矿床定位。矿床成矿作用经历了同生沉积成矿、后生改造和表生作用3个阶段,成矿年龄为85Ma、（41±5）Ma和6～13Ma。在总结矿床成矿地质特征、成矿作用及地球化学特征基础上,建立了努和廷铀矿床成矿模式。 相似文献
8.
常规化探方法勘查砂岩型铀矿难以奏效。应用深穿透地球化学方法系列中的元素活动态测量法在鄂尔多斯盆地砂岩型铀矿上的试验结果表明,几种U元素活动态在矿体上方都有异常出现,特别是其中的粘土吸附态U含量级别高、异常衬度大。因此,土壤粘土吸附态U测量法是本区化探找铀矿的有效方法;取样深度和取样粒级分别以60～90cm和-120目为宜;采用400m的取样点距基本不影响本区砂岩型铀矿的找矿效果。在盆地东北部应用土壤粘土吸附态U测量法预测了3个有利地段,并在其中1个地段的深部发现了较好的铀矿化。 相似文献
9.
沽源-红山子地区中生代火山作用与铀成矿关系 总被引：1，自引：0，他引：1
根据沽源-红山子地段中生代火山作用的时间,火山岩的主量元素、微量元素、稀土元素构成等特点,笔者将区内火山活动划分为早白垩世早期和早白垩世晚期两个旋回,将火山岩划分为以粗面质岩石为主的碱性系列和以流纹质岩石为主的亚碱性系列。本区中生代岩浆作用与铀成矿的关系主要表现在：（1）铀成矿受多岩浆系列共存地段控制;（2）铀成矿受晚期岩浆旋回的超浅成酸性斑岩体控制;（3）与铀成矿密切的斑岩体表现为壳幔作用的成因特点;（4）成矿火山岩表现出高硅和高钾的化学成分特点。 相似文献
10.
铀储层结构与成矿流场研究:揭示东胜砂岩型铀矿床成矿机理的一把钥匙 总被引：2，自引：0，他引：2
以鄂尔多斯盆地北部的砂岩型铀矿为目标,在铀储层形成发育的沉积学背景研究基础上,重点通过砂分散体系、沉积物粒度、隔挡层厚度和孔隙度的定量分析,精细地刻画了直罗组铀储层的外部几何形态和内部复杂结构,充分展示了铀储层的定量非均质性。依据盆地构造充填演化阶段、铀成矿年代学和地学空间信息三维可视化平台,分别对5个演化阶段的古地貌进行了恢复,并对不同演化时期的铀储层空间位置给予了准确定位,从而揭示了直罗组铀储层从沉积到接受铀成矿再到铀矿被改造期间的空间形态演化历史。在盆地构造充填演化研究、古地貌恢复和铀储层定量非均质性分析的基础上,重建了5个不同时期古地下水系统结构和参数的空间变化面貌,并运用地下水数值模拟方法再现了研究区5个演化阶段成矿古流场的特征及其演化规律。综合分析认为,铀储层的空间演变和内部非均质性制约了成矿流场的基本格局,成矿流场又无疑控制着层间氧化带的发育和铀成矿。当铀储层形成期的古水流方向与主成矿期地下水流场方向总体一致时有利于铀成矿,而当两者流向垂直时则成矿效率降低。 相似文献