Mineralogical Characterization Using X-ray Diffraction for Laterites of Swarnagadde Plateau, Western Ghats, Karnataka

Abstract: Laterites comprising the Swarnagadde plateau of Western Ghats on the south-western margin of peninsular gneissic complex. Laterites generally cap the granitic-gneiss and found plateau and coastal plains of the study area. A thick residual laterite-cappings have been formed during the Tertiary period due to intense and prolonged tropical weathering is the only major geological event of the area. Laterites are the products of intense sub aerial weathering in which Fe and / or Al content is higher and Si content is lower than in merely Kaolinised parent rocks. XRD analyses for identification of different mineral phases taken up and gibbsite, boehmite, kaolinite, goethite, anatase, hematite and other minerals have been identified in most of the laterite and altered rock samples, comprehensive peak data is presented in tables. Gibbsite and anatase show a gradual increase from reddish brown phase to white phase. Goethite and hematite show a decreasing trend from reddish brown to white phases of laterites. Kaolinite remains more or less uniform in all the phases except the clay zone in which it decreases. It increases slightly in laterites and becomes predominant in this saprolite horizon.

Keywords: Gibbsite, Weathering, XRD analysis, Reddish brown, Laterites.