高校地质学报2018，Vol.24Issue(1)：13-32,20.DOI:10.16108/j.issn1006-7493.2017064
诸广南部产铀花岗岩长江岩体中的绿泥石和铀源矿物研究
Study on Chlorites and Uranium-source Minerals of Uranium-ore-bearing Changjiang Granite in Southern Zhuguang Composite
摘要
Abstract
Changjiang granite is one of important uranium-ore-bearing granites in the southern Zhuguang granitic composite,northern Guangdong province.In this paper,we present a systematical on mineralogical characteristics of chlorites and accessory minerals and their alteration in the Changjiang granite,by using electron-microprobe analysis and scanning electron-microscope analysis.We found that uranium mineralization was related to the chloritization of biotite by reducing-redox-state hydrothermal fluid in the pre-mineralization stage. The chloritization of biotite altered the original U-bearing accessory minerals of the granite and formed new U-bearing minerals such as coffinite near the chlorite.Uranium in the newly formed U-bearing minerals can be easily released into fluid under circumstance of later hydrothermal fluid being in slightly oxidizing state in the mineralization stage. Accessory minerals in the Changjiang granite include zircon, apatite, coffinite-thorite, uraninite and monazite. Among these accessory minerals, uraninite, uranothorite and coffinite are thought of important uranium-source minerals of the Changjiang granite because of their high uranium content that is readily released during later alterations by oxidizing fluids. Monazite has a moderate quantity of uranium that is potentially able to be liberated when it is altered to synchsite.Such a process only occurs during chloritization of major minerals such as biotite that enclosed the monazite. Therefore monazite is a potential uranium-source mineral. Zircon is not a uranium-source mineral because uranium in zircon remains stable and not released even under hydrothermal alteration.Other minerals like allanite and apatite have little uranium which is even below the detection limit of electron-microprobe, are thus not uranium-source minerals of the Changjiang granite.关键词
长江岩体/绿泥石/副矿物/热液蚀变/铀源矿物Key words
Changjiang granite/chlorite/accessory minerals/hydrothermal alteration/uranium-source minerals分类
天文与地球科学引用本文复制引用
张丽,孙立强,陈卫锋,伏顺成,付宏宁,高爽,魏文芳,沈渭洲,凌洪飞..诸广南部产铀花岗岩长江岩体中的绿泥石和铀源矿物研究[J].高校地质学报,2018,24(1):13-32,20.基金项目
中国核工业地质局十三五高校铀矿地质科研项目 （）
