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砂岩铀矿体定位条件的铀、钍含量及其放射性同位素研究 总被引:2,自引:2,他引:0
以512矿床为例,研究了砂岩铀矿体铀、钍含量及其放射性同位素分布规律,由此讨论铀矿体的定位条件。结果表明:①在整个层间氧化带中岩石的钍含量变化不大,表现出钍化学性质的不易被淋洗、迁移、富集的惰性特征;②铀含量从强氧化带到弱氧化带直至矿化带逐渐升高,由矿化带到还原带逐渐降低,铀含量分带性反映了氧化环境铀溶解迁移、还原环境水解沉淀的过程;③铀含量大于100μg/g是砂岩铀矿体的定位条件;④放射性同位素比值作为铀矿体定位条件因矿体所处时期不同而不同;后期矿体放射性同位素定位条件为1≤234U/238U≤2,0≤230Th/238U≤0·2,234U/230Th>1;前期铀矿体放射性同位素定位的标准为0·75≤234U/238U≤1,0·5≤230Th/238U≤1。 相似文献
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Five gas geothermometers based on the concentrations of CO2,H2S,H2,CH2,N2 and Ar in fumaroles and wet-stem wells are applied to estimating subsurface temperatures in the Hveragerdi high-temperature geothmal field,SW Iceland,The results for fumaroles indicate that the calculated subsurface temperatures decrase from the northern part to the southern part of the field.The CO2-geothermometer gives the highers temperature values,with an average of 256℃ for the northern part,and 247℃ for the southern part.The H2S-geothermometer reveals an aquifer temperature of 211℃ for the northern part,and 203℃ for the southern part.The H2-geothermometer gives an average subsurface temperature of 229℃ for the northern part,and 184℃ for the southern part,which agerees excellently with the measured temperatures in wet-steam wells.The measured borhole temperatures in the field range from 215℃ to 230℃ for the northern part,and from 167℃ to 198℃ for the southern part.The CO2/H2-geothermometer gives the lowest subsurface temperature values,with an average of 203℃ for the northern part,and 143℃ for the southern part,The CO2/N2-geothermometer gives 249℃ for the northern part and 235℃ for the southern part.For the data from wells,the CO2-, H2S-,and H2-geothermometers,give average subsurface temperatures of 247℃ for the northern part and 246℃ for the southern part,213℃ for the northern part and 220℃ for the southern part,and 217℃ for the northern part and 216℃ for the southern part,respectively.The CO2/H2-geothermometer indicates an average subsurface tem,perature of about 200℃ for both the northern part and the southern part.The CO2/N2-geothermometer gives an average subsurface temperature of 180℃ for the northern part and 259℃ for the southern part.The discrepancy between the estimeated subsurface temperatures obtained by the various gas geothermometers has been explained in this paper.By integrating the solute geothermometric results,mixing model studies and gas geothermometric results.the maximum subsurface temperatures of the Hveragerdi high-temperature geothermal system may be considered to be about 240-260℃, 相似文献
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在热勘探过程中 ,建立在水 -岩平衡基础上的地热温标方法 ,常被用来评价地下热储温度。本文采用多矿物平衡图解法和Na -K -Mg三角图解法 ,研究西藏高温及江西中低温地热流体的平衡状态 ,从而为地热温标的选择提供了理论依据。 相似文献
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江西省横迳温泉区地热气体地球化学 总被引:2,自引:0,他引:2
从赣南横迳温泉区采集10个水样并分析了温泉及冷泉的水化学成分,认为热水起源于大气降水补给。在此基础上,还在温泉区采集了4个气样,测定了气体组分的含量及氦同位素.以及CO2和CH4的碳同位素。研究结果表明:横迳地区温泉气中CO2的含量很高(>96%),δCCO2较重(-4.43‰~-5.50‰),属幔源CO2;He同位素特征值(R/Ra)变化于1.36~2.11之问.均大于1,有幔源He的加入;本区温泉气的的组合类型为二氧化碳幔源温泉气,从整体上来说属于幔源无机成因气,是地幔脱气的产物。 相似文献
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邹家山铀矿床碱交代蚀变广泛发育,与铀成矿作用关系极为密切。笔者通过野外宏观地质调查和室内岩相学、电子探针分析、常量及微量元素化学分析等方法,初步查明该矿床碱交代型矿石的矿物交代蚀变顺序为钠交代、钾交代、硅质交代。碱性成矿热液先是富Na,而后富K,且两者成分相似,但富K热液更利于铀成矿。与正常碎斑熔岩相比,碱交代型矿石SiO2含量减少,K2O或Na2O、Al2O3、Fe2O3、MgO、P2O5、CaO和U、Th、Zr、Hf、Sm、Ti及REE含量明显增高。与钾交代型矿石相比,钠交代型矿石Rb和REE含量较少,稀土分异强。碱交代作用有利于副矿物蚀变并释放铀,有利于对地层中铀的萃取,有利于铀的稳定迁移。 相似文献