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| 吐哈盆地西南缘砂岩型铀矿地质地球化学基本特征 | |
| 引用本文： | 吴伯林,权志高,魏观辉,彭新建,王金平,李占游,徐高中,刘池阳,张复新.吐哈盆地西南缘砂岩型铀矿地质地球化学基本特征[J].矿床地质,2005,24(1):34-43. |
| 作者姓名： | 吴伯林 权志高 魏观辉 彭新建 王金平 李占游 徐高中 刘池阳 张复新 |
| 作者单位： | 1. 西北大学大陆动力学教育部重点实验室,陕西,西安,710069;中国核工业地质局203研究所,陕西,咸阳,712000 2. 中国核工业地质局203研究所,陕西,咸阳,712000 3. 核工业总公司地质局,北京,100013 4. 西北大学大陆动力学教育部重点实验室,陕西,西安,710069 |
| 基金项目： | 核工业地质局科技基金(200010100001)，科技部科技攻关项目(2001BA609A_07_13)，国家重点基础研究发展计划(973计划)项目(2003CB214607)联合资助 |
| 摘 要： | 文章通过对含矿目的层及其渗透性的分析、与成矿作用有关的常量和微量元素及部分特征性地球化学指标如有机碳含量、全硫含量、三价铁和二价铁比值的分析，以及流体包裹体成分和物理化学参数的测试，配合铀、铅、碳、氧、硫同位素的分析等方法，综合分析研究区内砂岩型铀矿的地质地球化学基本特征，认为：吐哈盆地西南缘砂泥岩互层地层结构完整且延伸稳定，属弱渗透一渗透性地层，对砂岩型铀矿成矿比较有利。据常量和微量元素分析，认为铀成矿存在着明显的地球化学分带性，其中，氧化带以有机碳和全硫(∑s)含量低、Th／u和Fe2O3／FeO及Ra／U比值高为特征；过渡带(成矿带)以Th／U比值低、∑S、Mo、Re含量高为特征；还原带则以明显的低Fe2O3／FeO、Ra／U比值，高有机碳含量为其特征。其他微量元素如Cu、Pb、Zn、Cr、Co、Ni、zr等及稀土元素在成矿过程中并未得到明显富集。经对相关岩石的铀．镭平衡、气液包裹体及相关同位素的研究，认为铀成矿具有多期次、年代新且集中于第三纪的特点；含矿目的层煤成气提供了成矿所需的还原环境；成矿作用铀源主要来自于含矿目的层本身；铀成矿古流体属低温浅成热液且主要来源于大气降水。 |
| 关 键 词： | 地球化学 砂岩型铀矿 铀成矿 地球化学分带 古流体 同位素 渗透性 煤成气 |
| 文章编号： | 0258-7106(2005)01-0034-10 |
Basic geological and geochemical characteristics of sandstone type uranium deposits in southwestern margin of Turpan_Hami Basin |
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| WU Bo_lin,QUAN Zhi_gao,WEI Guan_hui,PENG Xin_jian,WANG Jin_ping,LI Zhan_you,XU Gao_zhong,LIU Chi_yang and ZHANG Fu_xin.Basic geological and geochemical characteristics of sandstone type uranium deposits in southwestern margin of Turpan_Hami Basin[J].Mineral Deposits,2005,24(1):34-43. | |
| Authors: | WU Bo_lin QUAN Zhi_gao WEI Guan_hui PENG Xin_jian WANG Jin_ping LI Zhan_you XU Gao_zhong LIU Chi_yang and ZHANG Fu_xin |
| Institution: | WU Bo_lin~1,2,QUAN Zhi_gao2,WEI Guan_hui2,PENG Xin_jian3,WANG Jin_ping2,LI Zhan_you2,XU Gao_zhong2,LIU Chi_yang1 and ZHANG Fu_xin1 |
| Abstract: | In order to understand clearly the favorable geological and geochemical factors for mineralization and reveal the physical_chemical characteristics or genesis of ore fluids as well as the metallogenic environment and its dynamic evolutionary process in this area, the authors have studied comprehensively geochemical characteristics of the sandstone type uranium deposits. The means adopted included the analysis of the target stratum and its permeability, the determination of major and minor elements and the analysis of partial characteristic geochemical indexes such as organic_carbon, total sulfur and Fe~3+ /Fe~2+ ratios as well as physical_chemical parameters, together with the uranium, carbon, lead, oxygen and sulfur isotopic determination. It is held that the stratigraphic structure of the interbedded sandstone and mudstone on the southwestern margin of Tupan_Hami basin is perfect and stretches persistently, and that the weak to strong stratigraphic permeability is favorable for the formation of sandstone type uranium deposits. According to the analysis of major and minor elements, the authors considered that there exists prominent geochemical zoning in the uranium deposit. The oxidized zone is characterized by low organic carbon and sulfur and high Th/U, Fe_2O_3/FeO and Ra/U ratios. The transitional zone is noted for low Th/U ratio and high S, Mo and Re contents. The reduction zone is featured by low Fe_2O_3/FeO and Ra/U ratios and high organic carbon content. Other minor elements such as Cu, Pb, Zn, Cr, Co and Ni as well as REE like Zr were not obviously concentrated in the process of mineralization. According to equilibrium coefficients of uranium and radium, features of fluid inclusions, isotopic characteristics of lead_uranium ratio, carbon, hydrogen, oxygen and sulfur, it is thought that the uranium mineralization is relatively young in age and multiple in stage, with the main ore_forming phases concentrated in Tertiary period, that the coal bed gas in the ore_bearing target stratum provided the reduction environment for mineralization, that the ore source was from the ore_bearing target stratum itself, and that the paleo_fluid was the low_temperature epithermal hydrothermal solution derived mainly from meteoric water. |
| Keywords: | sandstone type uranium deposit geology and geochemistry mineralization of uranium deposit geochemical zonation paleo-fluid isotope permeability coal bed gas |
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