Characterising the Ongole Coastal Dunefield of SE India: Formation and Temporal Constraints

Abstract

The Ongole coastal dunefield (OCD) is about 20 km long and 2.5 to 3 km wide, and is located to the east of Ongole town between the mouth of the Paleru river in the south and a small creek in the north. Much of the dunefield lies 3–5 m above sea level with some large dune ridges reaching 10–12 m. The area landward of the dune field consists of an extensive marsh. Optically stimulated luminescence (OSL) dating of 12 sub-surface sediments from three sites near the western edge of the dunefield gives almost concurrent age of 5.1±0.4 ka. Radiocarbon dating of one shell from a similar location also corroborates the OSL age while the age of another shell taken closer from the modern shoreline gives a date of 3.29±0.5 ka. The age of the deposits and morphology of the dunefield indicate that it was probably initiated on some form of barrier system at the end of the Holocene transgression.