Metallogenic mechanism of Pingguo bauxite deposit,western Guangxi,China:Constraints from REE geochemistry and multi-fractal characteristics of major elements in bauxite ore  

作　　者：CAO Jing-ya WU Qian-hong LI Huan OUYANG Cheng-xin KONG Hua XI Xiao-shuang 曹荆亚;吴堑虹;李欢;欧阳承新;孔华;奚小双

机构地区：[1]Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring of Ministry of Education(Central South University),Changsha 410083,China [2]School of Geosciences and Info-Physics,Central South University,Changsha 410083,China [3]Department of Resources Science and Engineering,Faculty of Earth Resources,University of Geosciences,Wuhan 430074,China [4]Engineering Research Center of Hunan Earthquake Administration,Changsha 410001,China

出　　处：《Journal of Central South University》2017年第7期1627-1636,共10页中南大学学报（英文版）

基　　金：Project(GX2007CAQB01)supported by the Key Research Project of Aluminum Corporation of China Limited;Project(41502067)supported by the National Natural Science Foundation of China

摘　　要：Major and REE geochemistry and multi-fractal analysis of two types of bauxite(primary bauxite and accumulated bauxite) ores were studied in Pingguo bauxite orefield in western Guangxi,China.The results of geochemical data show that the accumulated bauxite has a feature of high Al_2O_3 whereas relative low Fe_2O_3 and SiO_2 contents compared to the primary bauxite.The similar chondrite-normalized rare earth element(REE) patterns illustrate that they have a cognate relationship.However,the negative Ce anomalies of primary bauxite and positive Ce anomalies of accumulated bauxite indicate that the ore-forming system changed from reducing environment to oxidation environment.The results of multi-fractal spectrum and parameters of Al_2O_3,Fe_2O_3 and SiO_2 between primary bauxite and accumulated bauxite show that the distinct multi-fractal spectrum parameters reflect the different grade distribution between accumulated and primary bauxite ores.Metallogenic process from primary bauxite to accumulated bauxite is accompanied by the loss of diffluent elements(e.g.,Si and S) and enrichment of stable elements(e.g.,Al and Fe) in the surface environment.Among the rest,the migration mechanism of iron during the evolutionary process from primary ore to accumulated ore can be described as combined leaching and chemical weathering action with participation of sulfur.Major and REE geochemistry and multi-fractal analysis of two types of bauxite (primary bauxite and accumulated bauxite) ores were studied in Pingguo bauxite orefield in western Guangxi, China. The results of geochemical data show that the accumulated bauxite has a feature of high Al2O3 whereas relative low Fe2O3 and SiO2 contents compared to the primary bauxite. The similar chondrite-normalized rare earth element (REE) patterns illustrate that they have a cognate relationship. However, the negative Ce anomalies of primary bauxite and positive Ce anomalies of accumulated bauxite indicate that the ore-forming system changed from reducing environment to oxidation environment. The results of multi-fractal spectrum and parameters of Al2O3, Fe2O3 and SiO2 between primary bauxite and accumulated bauxite show that the distinct multi-fractal spectrum parameters reflect the different grade distribution between accumulated and primary bauxite ores. Metallogenic process from primary bauxite to accumulated bauxite is accompanied by the loss of diffluent elements (e.g., Si and S) and enrichment of stable elements (e.g., Al and Fe) in the surface environment. Among the rest, the migration mechanism of iron during the evolutionary process from primary ore to accumulated ore can be described as combined leaching and chemical weathering action with participation of sulfur.

关 键 词：GEOCHEMISTRY multi-fractality boxing-counting method METALLOGENIC mechanism Pingguo BAUXITE 

分 类 号：P618.45[天文地球—矿床学]