Mineralogy, Genesis and Classification of Soils of North-West Himalayas Developed on Different Parent Materials and Variable Topography

Mineralogy of sand, silt and clay fractions of six soil profiles developed under different parent materials and topography from Kangra district (HP) has been characterized. The light mineral fraction comprised highest of the total sand with quartz, feldspar and muscovite, and heavy fraction constituting 11.3 to 0.7 per cent with a number of minerals. Plagioclase feldspar was highly weathered. Biotite, augite and hornblende were also of weathered nature. The mineralogical make-up of clays determined by XRD, DTAITGA and IRA indicated the dominance of mica with a complex of 14 A (chlorite, smectite and vermiculite) and mixed layers. Mica was both dioctahedral and trioctahedral, and the chlorite trioctahedral. DTA identified gibbsite while IRA indicated the presence of amorphous alumina/iron oxide and allophane. Similarity in clay mineralogy indicated the dominant influence of parent material. Generally the soil profiles developed under well leveled land and/or in low land topographic situation had well developed textural and structural horizons. The genesis of these soil profiles is expressed by calcification! decalcification, illuviation and humification. Soil Taxonomy of these profiles has also been described.