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81.
82.
鄂尔多斯深盆气与铀矿化关系初探 总被引:24,自引:4,他引:24
深盆气是非常规的天然气藏。鄂尔多斯深盆气与铀矿化有密切关系,上古生界气源层铀含量丰富、易浸出,故也为铀源层。在铀源层成岩时所形成的压榨水(即深层水),经燕山期热事件快速增温增压,使铀的溶解度大大增加。此时也正是盆地生气高峰期,气压远远大于水压,气体推动深层水沿断裂向上扩散。在上覆透水层,由于地表水的参与形成复杂的气水地球化学垒,使铀沉积成矿。本文还总结了该类型铀矿的找矿准则。 相似文献
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东秦岭上宫金矿流体成矿作用:矿物学研究 总被引:6,自引:2,他引:6
通过对上宫金矿矿物学资料的研究,确定其成矿过程具有3阶段演化特征。早阶段以粗粒乳白色石英脉为标志,矿物破碎、变形明显,金和杂质成分含量低,形成于挤压构造背景下静岩压力的变质流体。中阶段发育细粒多金属硫化物-碲化物-自然元素组合,呈微细网脉浸染于共轭节理或裂隙,没有遭受变形,金和杂质成分含量高,自然金与其他矿物属共沉淀关系,由变质流体沸腾导致,而流体沸腾则由造山过程的地壳快速隆升剥蚀引起。晚阶段发育具梳状构造的石英-碳酸盐网脉,含金性较低,由静水压力的大气降水热液在伸展构造背景下贯入张性裂隙形成。矿床地质地球化学特征与造山型金矿一致,成矿过程同步于陆陆碰撞造山作用,属于典型的断控脉状造山型金矿,成因适合于CMF模式。 相似文献
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An experimental study on reduction of U (Ⅵ) by anaerobic bacteria, Shewane//a putrefaciens, is first reported here in China. The experimental conditions were: 35℃ and pH =7.0-7.4, corresponding to a physicochemical environments in which the sandstone-hosted interlayer oxidation-zone type uranium deposit formed in Northwest China's Xinjiang. Bacteria adopted in the present experiment, Shewanella putrefaciens, occur extensively in natural environment. Our study shows that nano-crystal precipitates of uraninite quickly occurred on the surface of the cells within one week. It was found that the pitchblende was characterized by a random arrangement of uraninite nanocrystals (2-4 nm) in it, significantly different from natural pitchblende in which uraninite nanocrystals are arranged in order. Finally, a possible mechanism of uranium biomineralization by microorganisms in the deposits is discussed. Our investigation may supply a technical train of thoughts for bioremediation of nuclear-contaminated water environments and for underground dissolving extraction of the sandstone-hosted uranium ores. 相似文献
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A simulated experimental reduction of U^v1 and the synthesis of uraninite by a sulfate-reducing bacteria,Desulfovibrio desulfuricans DSM 642, are first reported. The simulated physicochemical experimental conditions were:35℃, pH=7.0-7.4, corresponding to the environments of formation of the sandstone-hosted interlayer oxidation-zone type uranium deposits in Xinjiang, NW China. Uraninite was formed on the surface of the host bacteria after a one-week‘s incubation. Therefore, sulfate-reducing bacteria, which existed extensively in Jurassic sandstone-producing environments,might have participated in the biomineralization of this uranium deposit. There is an important difference in the orderdisorder of the crystalline structure between the uraninite produced by Desulfovibrio desulfuricans and naturally occurring uraninite. Long time and slow precipitation and growth of uraninite in the geological environment might have resulted in larger uraninite crystals, with uraninite nanocrystals arranged in order, whereas the experimentally produced uraninite is composed of unordered uraninite nanocrystals which, in contrast, result from the short time span of formation and rapid precipitation and growth of uraninite. The discovery has important implications for understanding genetic significance in mineralogy, and also indicates that in-situ bioremediation of U-contaminated environments and use of biotechnology in the treatment of radioactive liquid waste is being contemplated. 相似文献
88.
潮水盆地铀成矿水文地球化学研究 总被引:1,自引:0,他引:1
在分析潮水盆地自然地理、地质背景及水文地质特征的基础上,对盆地铀成矿水文地球化学特征进行了探讨。结果表明:潮水盆地为-渗入型自流水盆地,其深层地下水中铀存在形式为UO2(CO3)n^2-2n。;从盆地边缘到盆地中心具有明显从氧化环境到还原环境的水文地球化学分带特征,水中铀经历了由溶滤迁移到还原沉淀的矿化过程;在盆地北缘的照壁山-白芨芨、阿右旗-陶家井地区,西南部的平易-平山湖地区具备十分有利的铀成矿条件和良好的铀成矿远景。 相似文献
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从分析ETM各波段图像的信息特征入手,在黄土覆盖等环境因素干扰严重的地区,利用遥感技术对其铀矿化的信息进行了提取.在ERDAS软件的支持下,应用图像融合、波段比值、主成分分析、光谱指数等技术方法,对ETM遥感影像数据进行增强处理.其中,图像融合与传统的图像融合略有不同,是在进行图像融合前将原始图像(ETM1~5,7)进行低通滤波处理,使得融合后的图像既保留高分辨率数据的空间信息,又保留低分辨率数据的光谱信息.在对研究区的遥感数据进行增强处理后,选取有利波段组合,圈定了有利铀成矿的远景区. 相似文献
90.
M. A. Elburg P. D. Bons J. Foden J. Brugger 《Australian Journal of Earth Sciences》2013,60(4):611-631
Magmatism,metamorphism and metasomatism in the Palaeoproterozoic‐Mesoproterozoic Mt Painter Inlier and overlying Neoproterozoic Adelaidean rocks in the northern Flinders Ranges (South Australia) have previously been interpreted as resulting from the ca 500 Ma Delamerian Orogeny. New Rb–Sr, Sm–Nd and U–Pb data, as well as structural analysis,indicate that the area also experienced a second thermal event in the Late Ordovician (ca 440 Ma). The Delamerian Orogeny resulted in large‐scale folding, prograde metamorphism and minor magmatic activity in the form of a small volume of pegmatites and leucogranites. The Late Ordovician event produced larger volumes of granite (the British Empire Granite in the core of the inlier) and these show Nd isotopic evidence for a mantle component. The high‐temperature stage of this magmatic‐hydrothermal event also gave rise to unusual diopside‐titanite veins and the primary uranium mineralisation in the basement, of which the remobilisation was younger than 3.5 Ma. It is possible that parts of the Mt Gee quartz‐hematite epithermal system developed during the waning stages of the Late Ordovician event. We suggest that the Ordovician hydrothermal system was also the cause of the commonly observed retrogression of Delamerian metamorphic minerals (cordierite, andalusite) and the widespread development of actinolite, scapolite, tremolite and magnetite in the cover sequences. Deformation during the Late Ordovician was brittle. The recognition of the Late Ordovician magmatic‐hydrothermal event in the Mt Painter Province might help to link the tectonic evolution of central Australia and the southeast Australian Lachlan Fold Belt. 相似文献