Holocene sediments in the Mekong delta are characterized by 5 stratigraphic units: Q21
Q22
Q23
Q24
Q25, and correspond to thickness intervals of 0.5-40 m, 1-33 m, 0.8-25 m, 0.5-22.5 m, 0.5-10 m respectively. The stratigraphic units are mainly found in boreholes (Q21, Q22) and exposed to surface (Q22, Q23 Q24)
section in coarse to fine grained interbedding type, fine to coarse grained interbedding type to which contains much organic matter. Some mainly sedimentary structures consist of bedding types as horizontal/cross bedding (Q21), parallel/cross bedding (Q22), discontinous parallel wavy bedding or chaotic structure (Q21), discontinous parallel wavy bedding (Q22), irregular parallel bedding and chaotic structure (Q23)
colors of sediments are white grey, greenish grey, yellow, brown and black. Sedimentary depositional environments are fluvial (a), fluvial - marine (am) and marine (m). The average rate of sedimentary accumulation changes from 0.11 mm/year minimum to 11.5 mm/year maximum, an average rate is 5.8 mm/year with decreasing trend from Middle Holocene to present.