Mineralogy of Soils Developed on Alluvium in the Indo-Gangetic Plain (India)
1977
Sidhu, P. S. | Gilkes, R. J.
X-ray diffraction, electron microscopic, and petrographic techniques have been employed to study the mineralogy of four soils developed on the Indo-Gangetic alluvium in northwestern India. Sand and silt fractions are dominated by primary quartz. Other minerals present in these fractions include muscovite, plagioclase and alkali feldspars, amphibole, biotite, and chlorite. Illite, chlorite, and kaolinite have been identified in the clay fraction of each soil with smectite being present in one soil. Both muscovite and illite belong to the dioctahedral 2M₁ polymorph, whereas chlorite is trioctahedral. Quartz and feldspar grains appear to be unaltered and very angular. Although the studied soils show morphological and physico-chemical evidence of pedogenesis, mineral alteration has been minimal. The mineralogy of all the soils is very similar and no changes in the mineralogical make-up with depth in a particular pedon have been observed. Soil mineralogy can be related to the mineralogy of rocks in the source areas which contributed sediments. It is considered that insignificant post depositional weathering of sediments has occurred.
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