摘要
为了解赣中金滩岩体黑云母花岗岩和二云母花岗岩的岩石成因及其差异,探讨二云母花岗岩中铀的富集机制,利用电子探针对两类岩石中的黑云母进行了分析,并进行了岩相学和矿物化学研究。结果显示,黑云母花岗岩中的黑云母为镁质黑云母和铁质黑云母,二云母花岗岩中的黑云母为铁质黑云母。黑云母花岗岩的结晶温度为660~722℃(平均692℃),二云母花岗岩的结晶温度为630~691℃(平均669℃);二云母花岗岩相对黑云母花岗岩具有更低的氧逸度条件,但二者都具有相当高的氟含量。综合黑云母化学成分和岩石地球化学特征,认为二云母花岗岩的源区富铀特征是导致铀富集并形成富铀花岗岩的物质前提,低温、低氧逸度和高F含量等物理化学条件是促使U富集的有利因素。
In order to understand petrogenesis of the biotite granite and two-mica granite in the Jintan pluton in central Jiangxi Province and petrogenetic differences between those two kinds of granites, and to explore the U enrichment mechanism in the two-mica granite, chemical compositions of biotites from the two types of granites are determined using electron microprobe in this paper. The results show that the biotites from the biotite granite belong to Mg-biotite and Fe-biotite, while the biotites from the two-mica granite belong to Fe-biotite. The chemical compositions of biotites suggest that the crystallization temperatures of the biotite granite vary from 660 ℃ to 722 ℃ with an average of 692 ℃;while those of the two-mica granite vary from 630 ℃ to 691 ℃ with an average of 669 ℃. Moreover, the two-mica granite was formed in relatively low oxygen fugacity than that of the biotite granite, though both of them contain relatively high F contents. Combined with chemical compositions of biotites and geochemical features of hosted rocks, we conclude that the uranium-rich source for the magma of two-mica granite is the material premise for the formation of uranium-rich granite. In addition, and physicochemical conditions of relatively low temperature, low oxygen fugacity and high F content are favorable to the uranium enrichment in the two-mica granite.
作者
陶继华
林秋伶
李鑫浩
曹俊
王安东
徐志添
TAO Ji-hua;LIN Qiu-ling;LI Xin-hao;CAO Jun;WANG An-dong;XU Zhi-tian(Fundamental Science on Radioactive Geology and Exploration Technology Laboratory,East China University of Technology,Nanchang 330013,China;School of Earth Science,East China University of Technology,Nanchang 330013,China;State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,China;Geologic Party No.293 of Guangdong Nuclear Industry Bureau,Guangzhou 510800,China)
出处
《矿物岩石地球化学通报》
CAS
CSCD
北大核心
2020年第2期267-282,共16页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
国家重点研发计划项目课题(2018YFA0404104)
国家自然科学基金项目(41303020,41763005)
东华理工大学放射性地质与勘探技术国防重点学科实验室开放基金项目(RGET1803)。
关键词
金滩岩体
华南
花岗岩
黑云母
U富集
the Jintan pluton
South China
granite
biotite
uranium enrichment
