Pilot Study On Quaternary Sedimentary Diatoms In Okinawa Through And The Variability Of The Kuroshio Current

Diatom　is　one　of　the　dominant　microfossil　groups　found　in　marine　sediments.　The　ecological　distributions　of　recent　diatoms　are　closely　related　to　physical,　chemical　and　hydrological　properties　of　the　water　masses　and　controlled　mainly　by　ocean　circulation.　The　diatoms　in　sediments　can　provide　lots　of　information　on　paleoceanographical　environments　and　paleoclimate　variations,　which　have　a　capacity　of　providing　invaluable　data　for　the　global　environmental　changes　and　climatic　processes.　The　fossil　record　of　diatoms　in　marine　sediments　is　essential　of　for　accurate　estimation　of　ocean　paleoenvironments.　　Based　on　a　quantitative　analysis　of　diatom　in　60　samples　from　sediments　of　Site　1202　recovered　by　ODP　Leg　195　and　9　surface-sediment　samples　collected　in　the　East　China　Sea　,and　intergrating　with　the　other　information　about　Oxygen　Isotopic　Stratigraphy　and　AMS　14C　dates　,this　paper　presented　the　changes　about　paleenvironments　and　palegeology　　since　16　ka　in　the　Okinawa　Through,　and　discussed　the　variability　of　the　Kuroshio　Current　during　the　Holocene.The　results　obtained　in　this　study　are　as　follows:　　1　1202B　core-samples　included　a　great　many　diatoms.　About　32　genere81　species　in　total　of　diatoms　have　been　identified　in　the　study.　And　only　10　species　distributed　from　bottom　to　top　in　core.　　2　Diatom　sediments　from　bottom　to　top　of　the　core　are　recognized　three　assemblages.　And　each　of　the　three　assemblages　represents　a　aggradations environment　,corresponding　to　seashore　environment,shallow　sea　environment　and　half-blue-water　or　blues　water　environment.　　3　The　Kuroshio　Current　　entered　into　the　Okinawa　at　9ka.