Evolution of late Holocene coastal dunes in the Cauvery delta region of Tamil Nadu, India

Abstract

Widespread occurrences of coastal dunes are observed in the Cauvery delta region of Tamil Nadu in Vedaranniyam in the south east coast of India. These dunes were studied to establish the chronology of their formation and to understand their evolution using optically stimulated luminescence (OSL) dating in combination with sedimentological studies (quartz grain surface morphology using scanning electron microscope, grain size and heavy mineral analysis). The study shows that on the south-east coast of India widespread periodic dune formation/reactivation has taken place during the late Holocene to very recent times due to a variety of reasons such as climatic variation and land use changes. The sand mobility index shows that the dunes in the area have been largely active during the past century in the southern part in Nagapattinam region and many of the crests were active in the northern Cauvery delta in Cuddalore region. The angularity and fresh appearance of sand in the inland dunes suggest a short distance of sand transport and a source proximal sand deposition was proposed for the dune formation. The study demonstrates the sensitivity of sand dunes on the south east coast of India to varying climatic conditions and changes in regional land use.