Characterization and Clay Minerals Composition of Soils Derived from Metamorphic Formation of Kumaon Himalayas

Mineralogical compositions of soils developed over metamorphic formation were carried out to know the physio-chemical bahaviour and mineralogical composition of clay fractions in soils of Kumaon Himalayas and their genesis. Soils vary greatly in their properties due to complex geology and geomorphology. Soils are mostly sandy loam to sandy clay loam in texture, strongly acidic to slightly acidic in reaction with pH varies from 4.8 to 6.3, rich in organic carbon, low in CEC. Clay mineralogical studies based on XRD analysis of surface and subsurface layers of selected pedons developed over Quartzite, granite, phyllites, schist and slate in soils of Kumaon hills of Uttarakhand were conducted and exposed to X-ray diffraction analysis. The x-ray diffraction pattern indicated that soils developed on quartzite contained highest amount of mica followed by interstratified and Kaolinite minerals. The content of kaolinite increased with soil formed through mixed layer phase. Kaolinite was the dominant mineral in soil-clay fraction of granite followed by interstratified minerals and micas. The content of interstratified minerals invariably decreased with depth, however it was observed reverse in case of soil development on quartzite where weathering is advance. However, soils developed on phyllites are dominant in interstratified minerals followed by Kaolinite and mica. Soils developed on slate were dominant in mica followed by Kaolinite. Interstratified minerals dominated in soils formed on schist followed by mica whereas, interstratified minerals followed by kaolinite and mica were abundant in soils formed on biotite-schist. The regular distribution of kaolinite and mica minerals in soil layers indicated the origin of clay minerals were pedogenic and the variations in clay minerals were caused by the parent material, weathering stage, topography and vegetation