Late Pleistocene forced-regressive deposits on the Sunda Shelf (Southeast Asia)

Regressive siliciclastic deposits from the central Sunda Shelf (Southeast Asia) were investigated by seismic surveying and sediment coring. High-resolution stratigraphy is favoured by the low shelf gradient and by a strong and focused sediment supply during periods of lower sea level. Three types of regressive deposits formed over the past fifty thousand years can be distinguished: (1) thick lens-shaped clinoform sediment ‘bodies’ up to 30 km wide which fill gentle depressions; (2) thin horizontally bedded deposits between the lens-shaped ‘bodies’; and (3) a thick progradation sediment wedge on the outer shelf and upper slope. The sediment cores reached the upper part of the regressive deposits and contain a regressive–transgressive succession of terrestrial, tidal and shallow-marine sediment facies. The lens-shaped sediment ‘bodies’ are interpreted as regressive deposits detached from each other, probably reflecting the interplay of low morphological gradient and minor sea-level fluctuations during Marine Isotope Stage 3, which resulted in the reduction of accommodation space and local depositional stacking. The Late Pleistocene sedimentation on the outer shelf was partly controlled by differential subsidence of the margin or by wave and wind-induced current action.