摘要
为了解矿化白岗岩是否遭受后期热液的叠加改造及铀成矿期次,对纳米比亚欢乐谷地区白岗岩稀土元素和微量元素地球化学特征进行了详细研究。研究表明,从未矿化到富矿白岗岩,稀土元素总量有明显的增长趋势,说明稀土元素的富集与白岗岩铀矿化具有同步性。该地区白岗岩铀矿化作用至少存在两期:一是岩浆结晶分异作用所形成的,为主成矿期,其球粒陨石标准化稀土元素分布模式表现为Eu亏损的轻稀土富集右倾型,U与Pb、Th、Co、Rb、Sr、Ni、Sb、Cs、Zr、Hf及REE关系密切,说明它们具有同源性;二是热液叠加改造作用形成的,主要发育于构造破碎带,其球粒陨石标准化稀土元素分布模式表现为Eu亏损的重稀土富集左倾型,U与Pb、Th、Sc、Cr、Co、Zn、Nb、Mo、Ta、Yb及HREE相关性高。
This paper focuses on the effect of later hydrotherm on mineralized alaskites and the stages of uranium mineralization. Here, we have reviewed the trace element and REE geochemical characteristics of alaskites and their relations with uranium mineralization in the Gaudeanmus area, Namibia. The results show that there is a significantly increasing amount of rare-earth elements from non-mineralized to mineralized alaskites, indicating the synchronization of REE enrichment and uranium mineralization. There are at least two stages of uranium mineralization： firstly, due to magmatic crystallization differentiation, the REE pattern is characterized by the right-inclining type with obvious Eu negative abnormity and LREE enrichment. This is the main mineralization stage, and uranium enrichment may have close relations with Pb, Th, Co, Rb, Sr, Ni, Sb, Cs, Zr, Hf and REE in this area, so they are evidently of homology; secondly, due to superimposed hydrothermal alteration, the REE pattern manifests as the left-inclining type with obvious Eu negative abnormity and HREE enrichment. At this stage, the correlations between U and Pb, Th, Sc, Cr, Co, Zn, Nb, Mo, Ta, Yb, HREE are excellent.
出处
《地球化学》
CAS
CSCD
北大核心
2016年第5期486-498,共13页
Geochimica
基金
非洲中南部古老地块铀矿综合识别评价技术及应用研究项目
关键词
稀土元素
微量元素
铀矿化
热液
白岗岩
欢乐谷地区
纳米比亚
rare-earth element
trace element
uranium mineralization
hydrotherm
alaskite
Gaudeanmus area
Namibia
