Clay mineralogical studies are made on four granite soils (residual) derived soils from different bio-climatic zones, i.e.; the temperate, warm temperate, subtropical and humid torrid regions. The four soils studied can be classified as brown forest soil of temperate zone (Mt. Kamagadake, Mie pref.), yellow brown forest soil (tentative name) of warm temperate zone, Yamaguchi pref., yellow soil (tentative name, Ishigaki is., Okinawa pref.) and, red yellow podolic soil of humid tropical zone (Amason high way, Altamira-Maraba, PARA, Brazil).
In brown forest soil, the clay minerals consist mainly of montmorillonite, gibbsite and meta-halloysite with a small amount of chlorite and illite. In the yellow brown forest soil, predominant clay minerals are meta-halloysite, Al-interlayered vermiculite, gibbite and illite. A small amount of chlorite, goethite, and mixed layer clay minerals of vermiculite and illite are also present. Yellow soil contains a large amount of meta-halloysite, some goeethite, and a little illite, hematite and lepidocrocite like mineral. The clay minerals in red yellow podzolic soil are dominated by well crystalized kaolinite, with some goethite and hematite. A very small amount of gibbsite are found only in the A, horizon. The present clay mineralogical study on four soils derived from similar parent rocks (granite) shows that the mode and process of the weathering or soil formation seem to be remarkably affected by the climatic condition, especially, by temperature and precipitation.
It is shown that there are distinct difference in the clay minerals species, kind and their combination and are also the differences in the profile distributions of clay minerals. Farthermore the differences in clay mineral compositions among the four soils are interesting from soil geographical viewpoint.