PRELIMINARY RESULTS FOR INVESTIGATION OF QUATERNARY DEPOSITIONAL ENVIRONMENT IN SONGJIHO LAGOON, KOREA BY EXTERNAL BEAM PROTON INDUCED X-RAY EMISSION (PIXE)

The sediment sequences in isolated basins, like coastal lagoonal system, reflect environmental change and sea-level variation. Lithologic, geochemical, paleontological and elemental analysis data from sediment core which clearly devided lamination layer and massive layer was investigated to reconstruct the late Holocene depositional environmental changes of the Songjiho Lagoon on the eastern coast of Korea. These data provide the history of the lagoon related to Holocene sea-level changes. This study explores the use of the multielemental capability of the PIXE technique to study elements for Al, Si, P, S, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Rb, Sr, Zr, and Cl in Songjiho Lagoon sediments. The use of the PIXE technique which has been firmly established as a non-destructive, rapid and sensitie method for multielemental analysis of core sample. Since Songjiho Lagoon has been tectonically stable and its provenance has not been changed the depositional environmental changes of this lagoon are deeply related to the variation of marine water influxes from East Sea (Sea of Japan), corresponding to the sea level changes during the late Quaternary. Our previous result showed that the well-lamianted layer(SJ99-7) is consistent with the absence of mollusks indicating the oxygen poor condition in stagnant brackish lagoonal system. The massive layer(SJ99-9) of very low sulfur content indicates a fresh water lake system isolated by the sand barrier. Our preliminary results show that the feasibility and usefulness of elements analysis in sediment core samples using PIXE technique for reconstruct depositional environment of the Sonjiho Lagoon. We will present the depositional environment related to sea-level change both lamination and massive layer with multielements more specifically.