Early human settlement and appearance oflarge-scale salt production in SE-Asia:Reconstruction of the coastline evolution and the palaeoenvironmental conditions in the north-eastern Mekong River Delta, Vietnam

Abstract

The Mekong River Delta in southern Vietnam is one of the Asian megadeltas that are hotspots for a growing population and intensified agriculture. As with other deltas worldwide, the evolution of the Mekong River Delta is closely linked to variations in sea-level, the amount of sediment discharge by the river system and the oceanographic properties off the river mouths. During the Holocene, all of these factors varied substantially and only in the mid- to late Holocene were environmental conditions favourable for delta progradation. The initial delta development was fast and rapidly formed a large delta plain. The new land offered an opportunity for prehistoric settlers, that inhabited adjacent areas since ca. 4000 years before present, to expand their living space southwards and to take advantage of the fertile soils. One of the outstanding places is the ca. 3000 year old site of Go O Chua in the northernmost delta. This site was potentially used to refine salt from seawater on an industrial scale and thusrepresents the oldest large-scale salt production centre in SE Asia. To manufacture salt on an industrial scale, the sea, as the source for the brine, ought to be close to the site in order to keep the transport routes short. The only available coastline reconstruction, however, suggests that the shoreline was far away from the site. To solve the problem of the spatial discrepancy between site and shoreline, it is necessary to re-evaluate thegeological and palaeoenvironmental evolution of the area. This is the major aim of this thesis.