HIGH RESOLUTION STUDY FOR GEOCHEMICAL PROXIES IN NORTH ATLANTIC OCEAN: IMPLICATIONS FOR PALEOCEANOGRAPHIC EVOLUTION

Abstract

High resolution study for the geochemical proxies (total organic carbon, carbonate, and inorganic elements) were conducted with respect to drilled sediments from North Atlantic Ocean (ODP Leg 162, Site 980) and compared with previously reported results to reconstruct the paleoceaographic evolution since last 500 ka. The geochemical proxies (TOC and CaCO3) had a larger fluctuation, showing cyclic variation. The results of spectral analysis indicate that both proxies in Site 980 have 100 ka cyclicity.Previous study based on geochemical elements concentration also indicated 100 and 400 ka cycle in nearby ODP Site 983 in North Atlatnic Ocean. This kind of cyclicity can be interpreted as orbital eccentricity, even though the 40 ka and 23 ka cycles were not presented in their study. Also, these cyclic geochemical variations in North Atlantic Ocean may thought to be related to paleoceangoraphic and paleoclimatological variation in North Atlatic Ocean. In particular, the Milankovitch cycle like variation in North Atlantic Ocean shows a slightly different cycle from site to site may reflect the paleoclimatological variation. At present, geochemical proxies for reconstruction of past sea surface temperature as well as flux from terrestrial areas will be developed in near future.reported results to reconstruct the paleoceaographic evolution since last 500 ka. The geochemical proxies (TOC and CaCO3) had a larger fluctuation, showing cyclic variation. The results of spectral analysis indicate that both proxies in Site 980 have 100 ka cyclicity.Previous study based on geochemical elements concentration also indicated 100 and 400 ka cycle in nearby ODP Site 983 in North Atlatnic Ocean. This kind of cyclicity can be interpreted as orbital eccentricity, even though the 40 ka and 23 ka cycles were not presented in their study. Also, these cyclic geochemical variations in North Atlantic Ocean may thought to be related to paleoceangoraphic an