Rapid flooding of the southern Vietnam shelf during the early to mid-Holocene.

ABSTRACT A new sea-level record derived from coastal deposits of the South Vietnam shelf covers the deglacial sea-level history between 13.0 and 9.0 ka BP. This record reveals a relatively constant rate of sea-level rise and matches well with model results based on the RSES-ANU global ice-sheet model. However, the sea-level observations reveal a significant discrepancy with model results based on the ICE-5G global ice-sheet model, which further questions the existence of Meltwater Pulse 1B The incised-valley deposits of the South Vietnam shelf also complete the deglacial coastal evolution of southern Vietnam. The regional sea-level records of the South Vietnam shelf, the Mekong Delta and the Cambodian lowlands reveal an offset of about 18 m between 9.0 and 8.2 ka BP. The shoreline retreat of more than 200 km related to this offset was mainly caused by the differential hydro-isostatic adjustment between the South Vietnam shelf and the Cambodian lowlands. However, the GIA-model results cannot fully explain this fast relative sea-level rise due to the topographic changes and, possibly, alternative melt-water sources not accounted for in the current models. [ABSTRACT FROM AUTHOR]