Abstract
(1) This paper deals with the serpentinization of amphibolite and the weathering of the serpentine derived from this amphibolite in Wakasa-machi, Tottori Prefecture (annual mean temperature 14℃, annual rainfall 1876 mm). (2) In the Serpentinization there are marked decrease of Si, Al, Ca, and alkali, and the increase of Mg and H_2O, in the weathering of serpentine Al and Fe increase, Mg decreases, and the following soils are formed : (I) dark green layer (below the subsoil) with coars granular structure, (II) redish-brown compact clayey subsoil, and (III) dark redish-brown clayey surface soil with granular structure and small humus (3.5%). (3) The Ni content of the amphibolite is 0.08% and it is increased to 0.14〜0.48% by serpentinization and weathering. Ni in the soils increases with depth. (4) In the early stage of weathering of serpentine the predominant clay mineral is halloysite, and with the progress of weathering kaolinite increases. The complex B consists of kaolinite, and the complex A_2 determined by the author's method consists of halloysite. (5) The free iron oxide in the dark green layer exists mainly in the form of limonite, and the iron of hematite form increases with the progress of weathering. (6) The serpentine soils are not rich in exchangeable bases but they have the high or moderate degree of saturation.
