Research status and prospect of surface sediment types in the China-ASEAN seas and adjacent areas

The map of surface sediment types is one of the main components of marine geological series maps, which is used to describe the distribution characteristics and variation patterns of seafloor sediments. There are significant differences in the investigation and research levels of seafloor sediment types in the China-ASEAN seas and its adjacent regions. The investigation level in Chinese seas is relatively high, and the bottom data is detailed and reliable. The Malacca Strait and the western Indonesian sea areas are relatively well-investigated, while most of the data in the western Pacific and northern Indian Ocean are lacking. The surface sediments in those areas are mainly composed of terrigenous clastic sediments, biogenic-terrigenous clastic sediments, deep-sea sediments, biogenic sediments, and volcanogenic sediments, which are divided into three sedimentary areas based on the present data. The sedimentary area of the East Asian continental margin sea is dominated by terrigenous clastic sediments, while the sedimentary area of the western Pacific continental slope is dominated by terrigenous clastic sediments and biogenic-terrigenous clastic sediments. The pelagic sedimentary area of the western Pacific and northern Indian Ocean is significantly dominated by endogenic sediments. The main factors affecting the distribution of seafloor sediments in the areas are sediment sources, topography, hydrodynamic environment, and tectonic activity. The compilation of the map of surface sediment types in the China-ASEAN seas and adjacent areas helps us to understand the distribution and patterns of sediment in the Pacific and Indian Oceans under different geological and climatic backgrounds.