陕西小花岔铀矿床岩浆演化及其对铀成矿作用的制约

发布时间：2018-03-26 09:54

本文选题：锆石U-Pb年龄　切入点：地球化学特征　出处：《现代地质》2017年05期

【摘要】：陕西小花岔铀矿床位于北秦岭造山带的东北部,矿体产于黑云母花岗伟晶岩和黑云斜长片麻岩的接触带同化混染区。为了厘定研究区花岗质岩浆演化与铀矿化作用的关系,对矿区内出露的花岗岩、花岗伟晶岩开展了详细的年代学和岩石地球化学研究。LA-ICP-MS锆石U-Pb定年结果表明:灰池子花岗岩体的形成年龄为(444±4.0)Ma;高山沟花岗岩株的形成年龄为(422±0.82)Ma;产铀黑云母花岗伟晶岩的形成年龄为(417±2.6)Ma;非含矿黑云母花岗伟晶岩的形成年龄为(413±1.8)Ma。地球化学数据表明:矿区花岗质岩石富集大离子亲石元素Rb、Ba、K,亏损高场强元素Nb、Ta。含矿黑云母花岗伟晶岩由于同化混染作用及与围岩的元素交换等原因,其基性组分Fe、Mg和挥发分F-含量较高,同一条黑云母花岗伟晶岩脉元素组成的差异是由于伟晶岩浆的同化分离结晶所致,在伟晶岩-黑云斜长片麻岩的接触带发生化学组分的元素交换,使得伟晶岩浆中U-F络合物发生分解,并且在良好的成矿条件下(围岩的铀含量较高、较好的构造环境)使得铀饱和沉淀形成铀矿物,如晶质铀矿等。小花岔铀矿床的形成主要受到了伟晶岩浆、围岩成分、岩浆热液中挥发分共同的作用,最终导致了铀矿床的形成。
[Abstract]:The Xiaohuacha uranium deposit in Shaanxi is located in the northeast of the North Qinling orogenic belt, and the orebody occurs in the contact zone of biotite granitic pegmatite and biotite plagioclase gneiss. In order to determine the relationship between granitic magmatic evolution and uranium mineralization in the study area, For granite exposed in the mining area, Detailed geochronological and petrogeochemical studies of granitic pegmatites. The results of U-Pb dating of zircon from LA-ICP-MS indicate that the age of formation of the Liqizi granite body is 444 卤4.0 MaA, the age of formation of the Gaoshanggou granite strain is 22 22 卤0.82 Ma, and the uranium-producing biotite granitic granitic granitic pegmatite. The age of formation of granitic pegmatite and biotite granitic pegmatite is 417 卤2.6 Ma and 413 卤1.8 Ma, respectively. Geochemical data show that granitic rocks are rich in large ion lithophile elements RbsBaNK, and depleted in high field strength elements, and depleted in ore bearing biotite granitic pegmatite. The geochemical data show that the granitic rocks are rich in large ion lithophile elements, and depleted in high field strength elements. Because of assimilation and contamination and element exchange with surrounding rock, The difference of elemental composition of the same biotite granitic pegmatite vein is due to the assimilation, separation and crystallization of pegmatite magma. Element exchange of chemical components occurs in the contact zone between pegmatite and biocline gneiss, which results in the decomposition of U-F complex in pegmatite magma and the higher uranium content in surrounding rock under good metallogenic conditions. The formation of Xiaohuacha uranium deposit is mainly influenced by pegmatite magma, composition of surrounding rock and volatile matter in magmatic hydrothermal solution. Finally, the formation of uranium deposits.
【作者单位】：中国地质大学地质过程与矿产资源国家重点实验室;中国地质大学(北京)地球科学与资源学院;陕西省核工业地质局二二四大队;
【基金】：中国地质调查局地质调查项目(12120114014401) 国家重点基础研究发展计划项目(2014CB440903)
【分类号】：P619.14

【相似文献】