摘要
晚泥盆世五指山组是桂西南地区重要的含锰地层,为一套硅质-泥质-灰质及其过渡相组成的深水台沟相沉积。锰矿体的形态和展布受岩相组合和构造条件的控制。本文分析了含锰岩系的主量及微量元素地球化学:含锰岩系的V/(V+Ni)、V/Cr、U/Th、Ni/Co值,U、V和Mo等氧化还原敏感元素的富集程度显示研究区含锰岩系形成于弱氧化-富氧环境。另外,含锰岩系的Fe/Ti、Al/(Al+Fe+Mn)、Si O2/Al2O3、Ba/Sr及Co/Zn比值及稀土元素Eu正异常特征均显示热水沉积物的特征,在Si O2-Al2O3、Fe/Ti-Al/(Al+Fe+Mn)、log U-log Th、(Ni+Cu+Co)×10-Fe-Mn关系图解中,样品投影点均落在热水沉积区内,反映锰的富集和成矿过程与热水活动的参与密切相关。含锰岩系的La/CeAl2O3/(Al2O3+Fe2O3)、100×(Fe2O3/Si O2)-100×(Al2O3/Si O2)、Fe2O3/(100-Si O2)-Al2O3/(100-Si O2)、Fe2O3/Ti O2-Al2O3/(Al2O3+Fe2O3)图解及稀土元素特征,均指示含锰岩系形成于被动大陆边缘背景。
The Xialei manganese deposit of southwest Guangxi occurs in the Wuzhishan formation of Late Devonian, which formed in a deep-water and trench setting, composed of a set of siliceous shale-gray matter and its transition phases.The morphology and distribution of manganese ore are controlled by lithofacies combination and tectonic conditions. This paper analyzes geochemical characteristics of major and trace elements of the manganese-bearing rock series.The results show that some geochemical parameters such as the ratios of V/（ V＋Ni ）, V/Cr, U/Th and Ni/Co, as well as the enrichment of redox sensitive elements （U, V and Mo） of the manganese-bearing rock series indicate that the deposit was formed in a weak oxidation to oxygen-rich environment. In addition, the ratios of Fe/Ti, At/（AI＋Fe＋Mn） , SiO2/Al2O3 , Ba/Sr, Co/Zn and positive Eu anomalies observed in REE patterns suggest typical hydrothermal sedimentary characteristics ; and the diagrams of SIO2-Al2O3, Fe/Ti-Al/（Al＋Fe＋Mn） , logU-logTh, （Ni＋Cu＋Co） ×10-Fe-Mn also show hydrothermal sedimentary characteristics, implying that hydrothermal activity played a vital role in the enrichment of manganese and the formation of the deposit. Furthermore,the REE characteristics and the diagrams of La/Ce-Al2O3/（ Al2O3 ＋Fe2O3 ） , 100×Fe2O3/SiO2-100×Al2O3/SIO2, Fe2O3/（ 100-SiO2 ）- Al2O3 / （ 100-SiO2 ） and Fe2O3/TiO2 -Al2O3 / （ Al2O3 ＋Fe203 ） all suggest that the manganese-bearing rock serious might formed at a passive continental margin.
出处
《地质与勘探》
CAS
CSCD
北大核心
2016年第1期25-39,共15页
Geology and Exploration
基金
国家“十二五”科技支撑项目(编号:2011BAB04B10)资助
关键词
晚泥盆世
锰矿床
地球化学特征
硅质岩
大地构造背景
Late Devonian, manganese ore, geochemical characteristics, siliceous rock, tectonic background
