9:15 AM - 9:30 AM
[MIS32-02] Past 60 kyr changes in the diatoms and glacial sediment supply to the Gulf of Alaska (IODP Exp. 341 Site U1419)
Keywords:IODP Exp. 341, Diatom fossils, Paleoenvironmental chang, Glaciation, Gulf of Alaska
In this presentation, we will present preliminary outlines, including analyses of diatoms, physical properties and foraminiferal oxygen isotopes, using the Holocene sediment samples drilled at the continental shelf (Site U1419). According to off-shore analyses, the estimated sedimentation rate at this site was 200 m/100 kyrs. The fossil diatom assemblages consists not only of several taxa which indicate the paleoceanographic changes but also of coastal and freshwater species and resting spores, which show the influences of continental environments and the nutrient fluctuation in water column. Their abundances with significant fluctuation show the paleoceanographic variation, changes in the development of ice sheets, the sedimentation rate with erosion and supply, and grain size of supplied sediments affecting the volume of pore water, as well as the dissolution of siliceous/calcareous microfossils during 100 ka to the present in the GoA.