Clay mineralogy of spodic horizons from cryorthods in Japan

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Abstract
Clay mineralogy of thirteen spodic horizon samples from seven Cryorthods developed on diverse materials (peridotite, andesite, lapilli, volcanic ash, slate, granite and granodiorite) in Chubu and Kanto, Japan was determined by successive chemical dissolutions with dithionitecitrate and 0.5 m NaOH-differential infrared spectroscopy in combination with chemical, X-ray diffraction, electron microscopic and thermogravimetric analyses. Thc major part of the soluble iron was found to be crystalline goethite. Presence of allophane (and imogolite) in the lower parts of the spodic horizons, but not in the upper parts, was interpreted as indicating a relatively limited supply of complexing fulvic acid from the overlying organic-rich horizons. The well-developed Al interlayers in the 2 : 1 type minerals associated with gibbsite suggest that the environment of the lower sub-horizons is rich in active aluminium,