The main sediments are made up of terrigenous clastic deposits. Other resedimented clastic constituents are: ooid, fossil clasts, plant clasts and glauconite, etc.

It is shown from the analysis results of grain size data that the sediments from the northern Okinawa Trough are mixture of terrigenous materials and volcanic ash during the Holocene epoch.

Elements are mainly terrigenous, clay (or fine muddy matter) is the major factor controlling the concentrations of heavy metals in sediments.