Himalayan Geology, Vol. 42 (2), 2021, pp. 312-320, Printed in India
Glacial deposits from Changme Khangpu glacier in Sikkim Himalaya, India and their mineralogical characterization
AMRITA SINGH1*, R.K. RANJAN2, V.C. TEWARI3, U. LAL4, A.G. BADEKAR5
1,4Dept. of Geography, Sikkim University, Gangtok, Sikkim, 737102, India
2,3,5Dept. of Geology, Sikkim University, Gangtok, Sikkim, 737102, India
*Email (Corresponding author): amritasingh.geo@gmail.com
Abstract: Glacial debris or till from Changme Khangpu Glacier catchment area has been studied for linkage between textural and bulk mineralogical characterization. Systematic sampling was done from the accumulation zone, snout, lateral moraine and outwash plains of the Changme Khangpu glacier. The textural studies using grain size analysis have been carried out for understanding the transportation and depositional processes, whereas, the mineralogical assemblages are investigated for tracing the provenance of glacial sediments. The results of textural analysis indicate that the high energy glacio-fluvial condition was responsible for the transport and deposition of sediments from accumulation zone and lateral moraine of the region, whereas the sediments from snout and outwash plain area reflects dominance of fluvial processes. The p-XRD analysis shows mineral assemblage of quartz, albite, anorthite, orthoclase, microcline, biotite, muscovite, and phlogopite, garnet, magnetite and goethite. These assemblages indicate sources for sediments from medium to high grade metamorphosed terrain of Central Crystalline Gneissic Complex (CCGC) of the northern Sikkim, whereas goethite indicates chemical alteration. Further, the finer size fraction contribution in these deposits suggest that glacial as well as fluvial processes are operating in the region while the mineralogical composition of finer fraction is similar to source rock mineralogy with no or very less alteration indicating dominance of physical weathering compared to the chemical weathering in the region.
Keywords: Changme Khangpu glacier, glacial deposits, mineralogy, fluvial process, Sikkim Himalaya
