RECORDS OF TERRIGENOUS DUST IN LACUSTRINE SEDIMENTS FROM DONGDAO ISLAND,SOUTH CHINA SEA

A lacustrine sediment core (DY6) was collected from the "Nietang Pond" on Dongdao Island,South China Sea (SCS). Geochemical,morphological,and mineralogical analyses were performed for the sediment samples. The results of major elements showed that the concentrations of Ti and Al in the sediment samples were much higher than those in three end-members (coral sand,guano and plants). Hierarchical clustering analysis of geochemical elements indicated that Al and Ti were exogenetic. Furthermore,according to the microscopic analysis,there are more acid-insoluble particles in the subsamples with high Ti (Al) contents,some of which showed similar morphological characters with the eolian dusts from Hefei,the loess-paleosol particles from Korea and the dust deposits from the north of SCS. The major elements concentrations of the acid-insoluble particles surfaces detected by X-ray energy spectrum revealed that these particles were mainly made up of silicate and quartz. Consequently,the accumulation of Ti and Al in the lacustrine sediments of Dongdao Island was quite possibly caused by the input of the terrigenous dust from the interior of Asia continent. The East Asian Winter Monsoon might be the transportation medium.