Mineralogy of two soil profiles—a black beidellite soil and a red fire-clay soil—from Madurai, India
Titel:
Mineralogy of two soil profiles—a black beidellite soil and a red fire-clay soil—from Madurai, India
Auteur:
Tomar, Krishan Pal Bystrom-Brusewitz, Ann Marie
Verschenen in:
GFF
Paginering:
Jaargang 99 (1977) nr. 3 pagina's 278-286
Jaar:
1977-09-30
Inhoud:
The results of a study of two soil profiles from Madurai, India, are presented. X-ray, DTA, EM and chemical methods have been used to evaluate the clay minerals present. Minerals in the coarser fractions have been studied. The main clay minerals have been classified with respect not only to group affiliation but also to a definite species within a group. The clay fraction of the black soil was found to be dominated by beidellite. The following formula was arrived at for the smectite clay of the upper horizon: (Si3.65Al0.35)(Al1.37Fe0.4334 Fe0.0224 Mg0.27)O10(OH)2M0.45+. The coarse-clay fraction contains chlorite, kaolinite, quartz, feldspar, rutile and anatase, in addition to the beidellite. The coarse-silt and the fine-sand fractions are dominated by quartz. Plagioclase and a smaller amount of potassium feldspar of both microcline and orthoclase types are present. Accessory minerals, such as amphiboles, garnet, zircon, rutile and sillimanite, have been identified. The red soil contains a fire-clay-type kandite mineral, as well as a more or less interstratified smectite mineral and illite. In the coarser fractions, quartz is abundant and a monoclinic potassium feldspar with all the characteristics of a high-temperature phase of sanidine type was identified.
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