Mineralogical properties of andisols of the Kitakami mountain range, Northeastern Japan
1999
Adjadeh, T.A. (Iwate Univ., Morioka (Japan). Faculty of Agriculture) | Inoue, K.
We studied the mineralogical properties of Andisols of the Kitakami mountain range. Soils of the northern and central parts of the mountain range contained higher levels of acid oxalate extractable silicon (Sio), aluminum (Alo), and iron (Feo) but smaller amounts of sodium pyrophosphate-extractable aluminum (Alp), iron (Fep), and carbon (Cp) than those of the southern part. Consequently, the soils of the northern and central parts of the mountain range contained large amounts of allophane and ferrihydrite whereas in the soils of the southern part Al (Fe)-humus complexes and 2:1 and 2:1:1 clays predominated. The amount of sand (20-2,000 mu-m) in the soils tended to decrease sharply from the north to the south of the mountain range. The soils of the northern and central parts of the mountain range contained larger amounts of heavy minerals in their fine sand fraction (20-200 mu-m). The soils of the southern part, on the other hand, contained larger amounts of fine-grained quartz (2-20 mu-m). All the soils of the mountain range contained substantial amounts of volcanic glass in their sand fraction. However, on a total soil basis, the amount of volcanic glass in the soils decreased from the north to the south of the mountain range and the trend was parallel to that of the sand content of the soils. From these results, we concluded that (i) the soils of the northern and central parts of the mountain range were derived mainly from tephras and (ii) the soils of the southern part were strongly influenced by long-range eolian dust
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