Lateritic and Bauxitic Materials

摘要: Abstract Lateritic profiles are very complex and mostly polygenetic. They have been widely studied but no generally accepted definition or classification of laterite exists. This chapter presents a review the various micromorphological characteristics lateritic bauxitic materials, without following specific genetic model. A standard profile includes several layers, from bottom to top: soft (mottled clay zone), hard (laterite sensu strictum for some authors), gravel-rich layer. The is characterised by redistribution hematite, forming network hypocoatings surrounding isolating kaolinitic cells. either nodular vermicular, with high concentrations hematite goethite common corrosion quartz grains. Nodules channels coated goethite-kaolinite coatings, whose genesis in not well understood. layer an accumulation allochtonous iron oxide nodules internal fabrics. In bauxites Al-rich laterites, types gibbsite enrichment, partly marked different crystal size ranges, observed thin sections. Although many descriptions laterites published disciplines, such as geology, pedology geomorphology, lack coherent concepts terminology greatly complicates attaining comprehensive view their characteristics.