QUATERNARY GEOLOGICAL MAP OF THE CONTINENTAL SHELF OF VIETNAM AT THE SCALE OF 1:1,000,000

Abstract

Eastern Sea of Vietnam is the world's largest semi-open sea and is bounded by archipelagos, islands, mainland and connected partially with Pacific and Indian Ocean. Its total water surface area is about 2,974,600km2. Vietnamese and foreign geoscientists have researched, got samples and mapped the geological map of Eastern Sea since 1960s but no guidance or right method was carried out to map, especially in presenting geological units on geological map. So that, in this article, the Geological Quaternary map of Eastern Sea is created by using group of methods, methodology and literatures for sediment, geophysics,... The methodology is systematization of research results of Vietnamese and foreign scientists on Quaternary geology in mainland and continental shelf. One of those results is the classification of sedimentary cycles in relation to sea level change in Quaternary. In seabed of Eastern Sea, there are 25 geological units of 7 sedimentary cycles, which includes 4 lithofacies Pliocene - Quaternary, 14 lithofacies in Pleistocene and 6 lithofacies in Holocene, coral reefs and volcanic rocks. Especially, there are 8 ancient shoreline zones that acted as geological boundary from 3500m to 25m water depth in the sea bottom.