The calcium-magnesium ratio of serpentinitic soils in various topographic locations in Sekinomiya, Japan: a potential criterion for the classification of the Dark-red Magnesian soils

in Foreign journals(other), 國外期刊(其他)
標題The calcium-magnesium ratio of serpentinitic soils in various topographic locations in Sekinomiya, Japan: a potential criterion for the classification of the Dark-red Magnesian soils
出版類型國外期刊(其他)
出版年度2011
AuthorsAtushi Nakao, 中尾淳, Tetsuhiro Watanabe 渡邊哲弘, T. Honda 本田竹義, Hseu 許正一, & 舟川晉也
開始頁30
頁數12
出版日期2011 / 6
其他編號0000
中文摘要

Four soil profiles at different topographic positions in Sekinomiya serpentinite terrain were investigated to understand in depth the characteristics of serpentinitic soils developed in Japanese climatic conditions. Their morphological, physicochemical, and mineralogical properties were characterized by way of comparison with those of typical serpentinitic soils previously investigated in other regions. Forest hill soils on summit, shoulder and footslope in the serpentinite terrain had a clayey cambic or argic subsurface horizons containing few amount of gravels. Their extremely low exchangeable Ca/Mg ratio (i.e. < 0.1) and clay mineralogy rich in chlorite are those typically shown in serpentinitic soils. On the other hand, soils in the paddy profile at alluvial fan indicated not only exchangeable but also total Ca/Mg ratios higher than empirical upper limit shown by serpentinitic soils in other regions. Furthermore, illite was dominant in their clay assemblages in spite of its negligible amount in serpentinite. These properties suggested a mixed parent material of serpentinite and felsic materials that had been carried as fluvial deposits from upper streams. Thus, the forest hill soils are recognized as a kind of serpentinitic soil while the paddy soil is not. Although transformation of chlorite into vermiculite or neoformation of smectite has been more or less observed in serpentinitic soils, such formations were not evident in the hill forest soils. It was unexpected that even at the surface horizon of Js F2 profile, which showed clay illuviation at subsurface horizon, secondary clay formation as described above was not evident. It seems that from the mineralogical point of view, the serpentinitic soils in the Sekinomiya serpentinitic terrain is at a very early wethering stage irrespective of their topographic positions.

期刊名稱Pedologist
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