Geomorphology of Goa and Goa Coast. A review

Abstract

This review on the geomorphology of Goa and the Goa coast included studies on the interpretation of LANDSAT images, aerial photographs and extensive field work. Physiographically the region can be broadly classified into: 1) the coastal tract; 2) sub-ghat region and 3) the high ranges of the Western Ghats. The drainage is dominatEd. by two directions: 1) directly to the Sea (from E to W) and 2) the NW or NNW direction in accordance to the geological structure. The overall landforms are the result of a combination of structure, lithology, intrusions, volcanism, denudation and Quaternary sea level changes. Laterite covers the major portion of Goa snd typically occurs as plateau landforms. The different laterite levels observed from 120 m level to sea level was the result of sea level fall. Remnants of the plateau surfaces showing deep lateritic weathering profiles are common in the northern part of Goa. The southern part presents a rugged topography with hills having an altitude upto 600 m. The coast is prograding along beaches and retreating along the cliffs and headlands. Fluvial, marine and aeolian features are common along the coast. The presence of laterite beds along the estuaries at a depth of 27 to 35 m below present sea level indicates a drowned valley. Based on the disposition of landforms the present coast is neither emergent nor submergent but it is a combination of both. Occurrence of laterites conglomerate beds, beach rock, beach ridges, old tidal flats beyond the present day high water line are the evidences of the sea level oscillations during the Quaternary