关键词: 红土, 网纹, 黏土矿物, 洞庭盆地

Abstract: The authors studied the characteristics of element geochemistry, mineral assemblage and microtexture of the white reticulate clay in the Quaternary laterite of the Dongting Basin with some experimental analysis methods, such as chemical analysis, X-ray diffraction analysis, IR and SEM analysis. The genesis of the vermiculate reticulate clay and the rhizomatic reticulate clay in the Quaternary laterite of the Dongting Basin are discussed. The formation of crannies or holes in the soil and the transference of soil elements are absolutely necessary conditions to form the white reticulate clay in laterite. The formation of crannies of the vermiculate reticulate clay results from the stratigraphical pressure and the seasonal fluctuating of the groundwater level. The formation of holes of the rhizomatic reticulate clay results from the decomposition of the botanic roots. The intense eluviation and weathering of soil with groundwater and run-off result in the enhancing of capacity of transference of some elements, such as Si, Al, Fe, Mn. The chemical reactions of the colloid particles in the soil water make those crannies or holes filled by some epigenetic clay minerals and quartz. Then a great deal of white reticulate clay comes into being in the Quaternary laterite of the Dongting Basin.

Key words: laterite, reticulate clay, clay mineral, Dongting Basin