GEOMORPHOLOGY OF GARHWAL HIMALAYA, PARTS OF CHAMOLI TEHRI UTTAKASHI & PAURI UTTAR PRADESH (UTTRARKHAND) INDIA

The Geological and Geomorphological study in Upper Ganga basin has been attempted in parts of de Uttarkashi,Chamoli, Pauri and Tehri districts an area of 10000 Sq.kms in parts of QA sheet 53Jand 53 N on 1:50000 scale of Garhwal Himalaya U.P presently known as Uttrakhand State of Union of India. Out of total area of study, an area about 3500 sq.Kms has been selected for detailed Geological, Geomorphological and Sedimentological study. The area of Upper Ganga basin consisting of Alaknanda,Bhagirathi,Bhilangna, Nandakini, Mandakini, Pindar, Dhauli- Ganga Bal- Ganga , Madhmeshwar Ganga and Berhi Ganga The Alaknanda is chracterised by six terraces followed by Bhagirathi with five terraces , Bhilangna Nandakini four terraces Mandakini /Pindar/Dhauli-Ganga /Balganga three terraces , Madhmshwar Ganga two terraces and Bberhi Ganga one terrace,amidst these Alaknanda is trunk stream and others are tributaries. Geomorphologically the area is divided in to seven geomorphic units viz High relief formerly glaciated area, Structural hills, Denudational hills, Area of mass wasting, High level dissected fans, river Terraces and Present day flood plain of Alaknanda and its tributaries . These units area developed in response to lithology to erosional land depositional activities and tectonic in which they are embedded. Each unit is characterized by drainage, diagnostic geomorphic landform elements and features, photo charcters and morphogenetic expression. The other geomorphic features and elements identified in the area are point bar, channel bar, alluvial fans ,talus cone , rock cut terraces fan cut terraces , abandoned channel ,epigenetic gorges, strand lines landslides ,rock fall scree and scree slope, retreating scarp, abandoned cirque, arêtes, threshold, horn peak and glacial lake. The area genetically comprised of terraces of three domains, viz. Glacial, Fluvio-glacia and Fluvial which represent distinct environment of sedimentation of Pleistocene, late Pleistocene and Holocene time during Quaternary period. The Glacial terraces are identified at an average elevation of 1150 m above MSL, the fluvio-glacial terraces at an average elevation of 975m above MSL and Fluvial terraces at an average elevation between 650 to 900 m above MSL.