Circum-Indian holocene sea-level database: a repository of distinct relative sea-level plots across the Indian Peninsula

Abstract

The Indian Peninsula is one of the most well-studied regions for Holocene sea-level fluctuations in the world, however, standardized relative sea-level datasets are missing. This study provides an archive of sea-level indicators (n = 162, 20 locations) along the western and the eastern sides of the peninsula, that have been used to develop Relative Sea Level (RSL) plots. Each dated sea-level indicator is recalibrated for its elevation based on tidal and tectonic correction, as well as age with reservoir correction, and have been separated into six zones based on coastal geomorphology and number of datasets. The database spans throughout the Holocene and covers sea-level depth/elevations from -45 m to +5 m from mean sea-level (MSL). Approximately 90 % of the dataset range from 8 ka to the present day. The first transgression is highly variable and identified between 8.5 - 8 ka BP in Gujarat (Zone 1), ~ 5.5 ka BP in Maharashtra (Zone 2), between 8 and 7 ka BP in Tamil Nadu (Zone 4) and between 8 and 7.5 ka BP in the Bengal coasts (Zone 6). No transgression above present sea-level is observed along Andhra Pradesh (Zone 5) (no data for Kerala - Zone 3). Further, Zones 1, 2, 4 and 6 show a strong uplift component (tectonic), whereas Zone 5 exhibits subsidence during the Holocene (Zone 3-insufficient data). Based on these findings, and given the region's coastal topography and tidal components, Zones 6 and 1 will likely undergo the largest coastal inundation, followed by Zones 5, 4, 2, and 3. These insights are critical in planning future coastal inundation measures across the Indian Peninsula.