| 何大芳,邹明亮,于玉帅,欧阳平宁,王前林,李杰.桂东北紫花坪岩体富Li淡色花岗岩岩石地球化学特征及其与铀成矿关系[J].地质找矿论丛,2018,33(3):335-345 |
| 桂东北紫花坪岩体富Li淡色花岗岩岩石地球化学特征及其与铀成矿关系 |
| Petrogeochemistry of Li-rich Zihuaping leuco-granites in northeastern Guangxi and the relation to uranium metallogenesis |
| 投稿时间：2017-05-18 |
| DOI：10.6053/j.issn.1001-1412.2018.03.002 |
| 中文关键词: 越城岭岩体 富Li淡色花岗岩 结晶分异 花岗岩成因 铀成矿作用 桂东北 |
| 英文关键词:Yuechengling pluton Li-rich leucogranite fractional crystallization genesis of the granite uranium mineralization the northeast Guangxi |
| 基金项目:国家重点研发计划"深地资源勘查开采"重点专项（编号：2016YFC0600205）、中国核工业集团公司项目（编号：地LTD1602）联合资助。 |
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| 中文摘要: |
| 锂、铀作为重要矿产资源，且在花岗岩中的富集部位存在交集，其成因问题长期备受关注。桂东北紫花坪岩体中的淡色花岗岩Li含量（质量分数）高达678.7×10-6（中细粒二云母花岗岩和中细粒白云母花岗岩），具有富集Li元素的特征。通过对其岩石地球化学特征及与铀成矿关系研究表明：淡色花岗岩具有相对较高的Na2O、Al2O3和F含量，以及较低的K2O、FeO、MgO和CaO含量，属于过铝质花岗岩；以离子电位5.7为界，淡色花岗岩中的微量元素随Li含量的增加，呈现出高离子电位元素含量增加而低离子电位元素降低的趋势，相对富集Rb、Ta和Hf，具有低ΣREE及重稀土富集特征；岩体中元素富集分带从早到晚、自下而上依次为LREE→Y→HREE→U（Ⅳ）→Zr-Hf→Nb-Ta→Li，花岗岩中的晶质铀矿早于稀有金属形成；铀矿石中As、Ni等元素富集，见地开石及钾交代现象，表明铀成矿过程中经历了热流体作用；结合区域成矿资料及上述结论认为，紫花坪岩体中的淡色花岗岩为泥质源区重熔的产物，其形成与岩浆高程度的结晶分异作用有关，相对靠近重熔界面顶部；淡色中细粒二云母花岗岩为区内主要含铀花岗岩，经历了晚期热流体作用，深部存在铀成矿的可能。 |
| 英文摘要: |
| Lithium and uranium are the main mineral resources and their enrichment positions in granite are related with each other. Leuco granite in Zihuaping pluton is characterized by Li enrichment, 678.7×10-6(in medium-fine grained mica-muscovite granite) and 1 092.0×10-6(in medium-fine grained muscovite granite). Study on relation between petrogeochemistry of the granite and Uranium metallogenesis shows that the leuco-granite is relatively higher in Na2O、Al2O3 and F and relatively lower in K2O、FeO、MgO and CaO and that they are peraluminous granites. Demarked by ionic potential value 5.7 trace elements get higher with increase of Li content in the granite, i.e. a tendency of increase of elements with high ion potential with decrease of elements with low ion potential. Elements. In addition Rb, Ta, Hf are relatively enriched and HREE concentration lower. The element concentration zoning in the granite is temporally (from early to late) and spatially (from top to bottom) LREE→HREE→U(IV)→(Zr, Hf)→(Nb,Ta)→Li. The uraninite was formed before rare metal minerals. see to the dickite formation and potassium replacement in uranium ore for enrichment of As, Ni and other elements which indicates that hydrothermal fluid incorporated in the U-ore-forming process. Combined with the regional metallogenic data it is considered that the Li-rich leucogranite in Zihuaping pluton are the products of the remelting of the muddy source region, and the formation is close to the top of the remelting interface and related to the high degree of crystallization of the magma. The medium-fine grained two mica granite is the main uranium-bearing granite in this region, which was exposed to late thermal fluid. U-prospecting is potential to depth. |
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