Morphostructural features of the lower Mekong plain

Abstract

For the first time a morphostructural scheme of the lower Mekong plain has been compiled based on new geological, geomorphological and geophysical data and space photoes as well as on deep drilling data. Three units have been recognised, such as structural-erosional low mountains, basalt plateau and marginal continental plain corresponding to tectonic down warping. The latter consists of denudational and erosional-accumulative plains, and sedimentary delta plain. Both positive and negative neotectonic structures are identified within the sedimentary plain, they are well pronounced in the topography and to a certain extent in geophysical fields pattern.

Comparative analysis of morphostructures of Mekong and Hanoi (North Viet-Nam) plains indicates moderate down warping at vast areas of Southern Viet-Nam, the process rate increasing through the Quaternary. The climatic factor significance for morpho- and lithogenesis is elucidated.

The author puts the Mekong plain to the class of down warping plains adjoining marginal seas (Western Pacific type).