摘要
The mineral composition of the bulk samples of the surface sediment in the eastern area off the Ryukyu Islands is studied with X-ray diffraction(XRD).It is found that the sediment consisting of smectite,illite+mica,kaolinite+chlorite,quartz,potash feldspar,plagioclase and calcite,is dominated by quartz,illite+mica,calcite and plagioclase,and kaolinite+chlorite and smectite occupy the second place with potash feldspar occasionally observed.According to the mineral composition,it is deduced that the sediment came from terrigenous,volcanic and biogenic sources.