摘要
通过对大田铝土矿矿床钻孔岩芯样品进行地球化学分析,探讨了矿床铝土矿矿石和围岩中的Li、Sc、Ga和稀土元素(REE)的分布特征。大田矿床赋矿层位为二叠系梁山组,研究发现含矿岩系中Li、Ga等元素有一定的富集特征。Li主要聚集在铝含量相对较少的的黏土矿物中,Ga在Al含量较高的土状铝土矿中未发生富集,但在剖面上与Al具有一定的相关性特征,并主要富集于含碎屑块状铝土岩下部,推测其分布形式受矿源岩演化作用的影响,与其它含铝矿物一起向下迁移富集。Sc主要以离子赋存的形式存在,其次为类质同象替代形式。对剖面上REE研究显示,含矿岩系在矿源岩风化淋滤过程中轻稀土元素(LREE)和重稀土元素(HREE)发生了一定程度的分馏,致使铝土矿层显示左倾的配分模式。虽然剖面上的脱硅作用未发育,但去铁作用使得含矿岩系中稀土元素与含铁矿物一起迁移,在底部的铁矿层中发生异常富集。
Based on geochemical analysis of samples of the bauxite ores and wall-rocks from drill cores of the Datian bauxite deposit,in this study,we have explored the enrichment and distribution characteristics of Li,Sc,Ga,and rare earth elements(REE).The bauxite orebodies occurred in the Permian Liangshan Formation(Fm.),with a certain enrichment of Li and Ga in the ore-bearing rock series.Li is mainly enriched in clay minerals with relatively low Al concentration.Ga was not enriched in the earthy bauxite with relatively high Al content,though Ga contents are certainly correlated with Al contents in bauxite ores and bauxite-baring rocks in the profile of the deposit,and Ga was mainly enriched in the lower part of the clastic bauxite layer.It is inferred that the Ga distribution was influenced by the evolution of bauxite source rocks and was migrated and enriched with other al-bearing minerals down to the lower part.Sc mainly existed in the form of ion-adsorption,followed by the isomorphism.The left-inclined REE distribution patterns of bauxite ores suggest that the bauxite ore-bearing rock series experienced a certain fractionation between the light rare earth elements(LREE)and heavy rare earth elements(HREE)in the weathering and leaching processes of bauxite source rocks.Although the desilication was not developed,the de-iron activity resulted in the downward migration of Fe and REE of the bauxite-bearing rocks series to the bottom of the bauxite layer for the extreme enrichment of Fe and REE.
作者
陈健
向震中
万斌
吴龙
万将
吴涛
周恩泽
赵龙桥
杨如春
谷静
CHEN Jian;XIANG Zhen-zhong;WAN Bin;WU Long;WAN Jiang;WU Tao;ZHOU En-ze;ZHAO Long-qiao;YANG Ru-chun;GU Jing(The Sixth Geological Team,Guizhou Province Bureau of Nonferrous Metals and Nuclear Industry Geological Exploration,Kaili 556000,China;State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《矿物学报》
CAS
CSCD
北大核心
2021年第4期485-493,共9页
Acta Mineralogica Sinica
基金
矿床地球化学国家重点实验室领域前沿项目(编号:SKLODG-2018-01)
贵州省科技支撑项目(编号:黔科合支撑[2019]2859号)。
