The geomicrobiology of bauxite deposits

作     者：Xiluo Hao Kwunlun Leung Rucheng Wang Weidong Sun Yiliang Li 

作者机构：Key Laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of SciencesGuangzhou 510640 China Department of Earth Sciences The University of Hong Kong Pokfulam Road Hong Kong China Graduate School of the Chinese Academy of Sciences Beijing 100039 China School of Geological Sciences ＆ Engineering Nanjing University Nanjing 210093 China 

出 版 物：《Geoscience Frontiers》 (地学前缘（英文版）)

年 卷 期：2010年第1卷第1期

页      面：81-89页

学科分类：0820[工学-石油与天然气工程] 081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程] 082002[工学-油气田开发工程] 

基　　金：supported by the Hong Kong University General Research Fund HKU703008P on‘Planetary Evolution of Ferric Iron Metabolism 

主　　题：Geomicrobiology Bauxite Microbial activity Microbial-mediated release of elements Biomineralization 

摘      要：Bauxite deposits are studied because of their economic value and because they play an important role in the study of paleoclimate and paleogeography of continents. They provide a rare record of the weathering and evolution of continental surfaces. Geomicrobiological analysis makes it possible to verify that microorganisms have played a critical role during the formation of bauxite with the possibility already intimated in previous studies. Ambient temperature, abundance of water, organic carbon and bioavailable iron and other metal substrates provide a suitable environment for microbes to inhabit. Thiobacillus, Leptospirilum, Thermophilic bacteria and Heterotrophs have been shown to be able to oxidize ferrous iron and to reduce sulfate-generating sulfuric acid, which can accelerate the weathering of aluminosilicates and precipitation of iron oxyhydroxides. Microorganisms referred to the genus Bacillus can mediate the release of alkaline metals. Although the dissimilatory iron-reducing and sulfate-reducing bacteria in bauxites have not yet been identified, some recorded authigenic carbonates and ＂bacteriopyrites＂ that appear to be unique in morphology and grain size might record microbial activity. Typical bauxite minerals such as gibbsite, kaolinite, covellite, galena, pyrite, zircon, calcium plagioclase, orthoclase, and albite have been investigated as part of an analysis of microbial mediation. The paleoecology of such bauxitic microorganisms inhabiting continental （sub） surfaces, revealed through geomicrobiological analysis, will add a further dimension to paleoclimatic and paleoenvironmental studies.