Holocene Sedimentation on the Vietnamese Shelf: From Source to Sink

25 sediment cores from modern water depths between 21 m and 169 m and two river samples from the Mekong and Red River have been investigated in order to characterize sedimentary processes, stratigraphy, provenance, distribution and sediment budget during the Late Pleistocene and Holocene on the Vietnamese Shelf. A stratigraphy, based on 45 AMS 14C dates was developed. The sediments could be assigned to 3 areas which are characterzied by different sedimentological conditions resulting in varying sedimentation rates (Northern Shelf 10 cm/kyr, Central Shelf 50 - 100 cm/kyr, Southern Shelf 5 - 10 cm/kyr). Investigations of major- and trace element as well as Sr- and Nd-isotopic composition of shelf and river sediments showed, that the sediments on the Vietnamese Shelf are mainly delivered by the small mountainous rivers and the Mekong. Together with denudation data taken from the literature a conceptual sediment buget for the Vietnamese Shelf was calculated. It shows that the small mountainous rivers of central Vietnam deliver the equivalent of ca. 25 - 60 % of the amount of sediment transported by the Mekong