抄録
Weathering products in a brown soil (sample S3) and in a partially weathered antigorite in yellowish brown color (sample A59b) were collected from the serpentinite zone in Sasaguri area, Fukuoka Prefecture, Japan. The products were studied by X-ray diffraction, transmission electron microscopy, analytical electron microscopy, infrared absorption spectrumand differential thermal analysis. Mineralogical composition of the brown soil are 14Å intergrade, halloysite, goethite and ferrihydrite associated with Si, and hematite. Si-containing goethite, Si-containing ferrihydrite, hematite and hisingerite were found in the weathered antigorite. The results suggest that leaching of Mg and Si from the serpentine minerals occurred at initial weathering stages. Precipitation of hydrous iron oxides and hydrous iron silicates may occur after the leaching of Mg and Si. Poorly crystallized iron minerals showed aggregate of microcrystalline materials (<100Å). The result suggests that the 14Å intergrade and halloysite were produced from weathered chlorite and/or mica minerals in the crystalline schist, or weathered chlorite in the vein at the serpentinite zone, or 2 : 1 layer silicates in eolian dust.
