Intertidal estuarine sediment grain size is one of the environmental parameters that can explain the interaction between the marine and terrestrial environments. Geostatistics has been widely used to model spatial distribution of many geological objects. However, there has been a few researches concerning with application to grain size distribution. The aim of this study is to clarify surface sediment distribution of tidal flats based on the geostatistical approach. A total of 116 surface sediment samples were collected from the tidal flats in Ba Lat estuary. Grain size of these samples was determined by means of sieve and pipette. Data of sand content (percent of fraction > 0.063 mm) in the sediments were characterized by ordinary kriging (OK) to model sediment distribution. In the study area, four sediment types could be recognized: sand, muddy sand, sandy mud and mud. The sandy sediment types are dominant from the near sea shoals (Con Mo, Con Vanh, Con Thu) to centre of study area. The muddy sediment types concentrate on from inner edge to centre of study area, where mangroves cover partly these tidal flats. These results can contribute to explain the hydro-dynamic and environmental pollution processes in the estuarine area.
