Neotectonic evolution of Coastal Rivers of Mangalore, Karavali Karnataka, India

Abstract

The geomorphic evolution of Mangalore is intimately influenced by Neo-tectonic activities that affected the West Coast and peninsular India that led to the upliftment of Sahyadri Range. Mangalore pediplain has preserved signatures of (1) An older cycle of River system that existed prior to the rise of Sahyadri and (2) Several phases of migration paths of the West flowing Sahyadri Rivers, reflecting geomorphic changes in the pediplain in response to the tectonic strains generated during the rise of the Sahyadri range and northward drift of the Indian subcontinent. The compressional stress derived from the phenomenon of Sea floor spreading is manifested in the Karavali pediplain, in the form of EW and NNW intersecting transform faults that activate periodically and trigger microseismic disturbances severe sea erosions or landslides under adverse hydrological conditions. Similarly under the regime of compressional stress, the Mangalore pediplain evinces evidences of sequential development of anticlinal upwarps that broke into horsts and grabens separated by escarpments. The Holocene fluvial evolution of Mangalore consisted of migration of the two Rivers in opposite directions with progressive passage of time in the Holocene. Fluvial geomorphology of Mangalore has also preserved evidences that substantiate shifting of trans-peninsular Mulki - Pulicat Ridge Axis from its original position northwards. The ongoing structural disturbances and micro-seismic and allied recent neo-tectonic activities imply that the processes responsible for the creation of the Sahyadri range have not died down yet and are very much in attendance even today. 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.