Geological setting, petrography and mineralogy of laterites from Swarnagadde plateau of Western Ghats, Karnataka

Abstract

The word “laterite” has been applied to such a diverse range of geomorphic features that it no longer has value as a precise descriptive term (Paton and Williams, 1972) [19]. The present paper gives an account of Geological Setting, Petrography and Mineralogy of Laterites from Swarnagadde Plateau of Western Ghats, Karnataka. The most widespread occurrences of laterites within the Western India have been recognized in a series of different geological-geomorphological settings, and are found in two distinct geomorphological zones. Mineralogical characterization of laterite and parent rocks could help in understanding the process of Lateritisation and bauxitization. While genesis of laterite is subjected to the process of alteration and it mainly decipher by the composition of preexisting rocks and also processes involved in lateralization/bauxitization. Mineralogy of lithomarge zone is predominated by kaolinite that of aluminous laterite zone by gibbsite. But, laterite and ferruginous laterite zones are predominated by both gibbsite and goethite with good amount of heamatite. In the entire lateritic weathering profile quartz occurs ubiquitously as the main resistant relic mineral. The occurrence of anatase and ilmenite is restricted to aluminous laterite zone.