IMPACT OF SEAFLOOR TOPOGRAPHY ON DISTRIBUTION OF CLAY MINERALS IN THE EAST PHILIPPINES SEA

We analyzed the clay mineral assemblages, contents and mineralogical characteristics for the 125 surface sediments recovered from the Parece Vela Basin. It is found that the clay minerals are mainly composed of smectite (average 49%), illite (average 35%) and chlorite (average 11%) with minor kaolinite(average 5%).Comparing the clay mineral assemblages and their crystallographic characters with the potential provenances, we suggest that smectite is mainly from the volcanic arc materials around the Parece Vela Basin and its distribution pattern may be mainly controlled by deep currents. Illite and chlorite are mainly derived from the Asian eolian deposits transported by wind. The spatial distribution of clay minerals indicates that illite dominates the lower terrain, while smectite is concentrated in the higher places near the Palau ridge and the Yap ridge. With the minimal effects of the volcanic material dilution and the influence of deep current erosion, the eolian flux in the deep East Philippine Sea can represent the actual contribution of Asian wind dust to the study area. It will be of great significance to extract the wind dust from the East Philippine Sea sediments for the further study of the paleoclimate evolution in the Asian continent.