Identification of grain size and mineral distributions in the surface sediments of Red river estuaries in Vietnam

Abstract

The mineral composition and grain size of 45 surface sediment samples from the estuaries of the Red River system were analysed to assess the dynamics and origin of the sediments. Five types of sediments are distributed in river mouths, which are coarse silt, very fine sand, very coarse silt, fine sand, and medium silt. The mineral contents in the sediment were as follows: quartz 46.0%, illite 18.3%, kaolinite 11.8%, chlorite 6.4%, feldspar 6.0%, goethite 4.4%, calcite 1.9%, gibbsite 1.7%, and amphibole 1.4%. Between grain size parameters and mineral compositions were positive and negative correlations. The positive correlations were between S0 and illite, kaolinite, goethite, calcite; between Md and quartz, feldspar, amphibole; between illite, kaolinite, chlorite, goethite together.  The
negative correlations were between quartz, feldspar, Md with illite, kaolinite, chlorite; between goethite with quartz, feldspar, Md; between amphibole with kaolinite; between gibbsite with quartz; between S0 and Md, quartz, feldspar, amphibole. There were two sediment groups: Group 1 was weakly dynamic, and Group 2 was strongly dynamic. The minerals in the sediments were mainly continental, characterised by illite, kaolinite, chlorite, quartz, feldspar, and amphibole, with other sources, including precipitation and weathering, being limited.