Occurrence of submerged Pleistocene stony corals and marine molluscs at Vazhakala near Cochin and their significance on sea level changes

Abstract

A well preserved, submerged assemblage of Scleractinian corals and marine molluscs was observed from a well cutting at a depth of 8 m from the present MSL and about 8 km inland, at Vazhakala near Cochin (Kerala). Based on the determination of age of a sample of Goniastrea retijonnis-a reef coral, it is suggested that the deposit is of Pleistocene Era. The sea level circa 40000 y B.P. at this region was about 7-8 m than the present and the coastline extended up to 8 krn eastward than the current. The Pleistocene coral and molluscan fauna reported herein do not display much variation from the present faunal elements known from the seas around India. It is suggested that a regression of sea during the Late Pleistocene resulted in the emergence of Cochin and suburbs and the physiography was subsequently modified by alluvial deposits from the rivers.