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Mineralogy and Micromorphology of Soils from Volcanic Tuffs in the Humid Tropics

1989; Wiley; Volume: 53; Issue: 6 Linguagem: Inglês

10.2136/sssaj1989.03615995005300060049x

1435-0661

D. H. Goenadi, K. H. Tan,

Geotechnical and construction materials studies

Abstract An investigation was conducted to study mineralogy, chemical characteristics, and micromorphology of three pedons from andesito‐dacitic volcanic tuffs in Banten, West Java, Indonesia. The soils were strongly acid, had clayey textures, argillic horizons, and base saturations <35% in the control sections. The clay distribution suggested two of the soils to be Hapludults whereas the third was a Paleudult. Kaolinite was the dominant clay mineral, though the clay fractions did not meet the definition for low activity clays because of their relatively high cation exchange capacity (CEC) values. The sand and silt fractions contained substantial amounts of weatherable minerals (>10%). Micromorphic characteristics supported pedological features in the field. The Ap horizons exhibited soil fabrics composed of skeletal grains and plasma, and granular to crumb micropedal structures. In contrast, the Bt horizons had soil fabrics showing large amounts of plasma, angular blocky microstructures, and the presence of argillans.