The Paleo-Lupar: Bathymetric and seismic evidence for a submerged Late Pleistocene river valley on the Sunda Shelf, off Sarawak

Abstract

This article presents bathymetric and seismic evidence of a submerged Late Pleistocene river valley on the Sunda Shelf, off Sarawak. The submarine feature identified as the Paleo-Lupar is detectable in digital elevation models (DEM) at water depths of about 40 m near the Lupar river mouth to more than 100 m to the north nearer the shelf edge. Bathymetric profiles revealed an ~30 km-wide submarine valley, with individual channels that, in places, can be more than 80 m deeper than the surrounding seabed. The Paleo-Lupar is one of several major paleo-rivers that drained the Sunda Shelf when sea level was lowest during the Last Glacial Maximum (LGM) around 21 ka BP and were subsequently submerged due to the sea level rise that has since occurred.