MIS 6 이후 동해의 고해양환경 변화 : 유공충 안정동위원소 분석

Abstract

Stable (oxygen and carbon) isotopic records in surface water were reconstructed for the past 250 ka, ranging from MIS (Marine Isotope Stage) 1 to the beginning of MIS 8, by analyzing the planktonic foraminifer Neogloboquadrina pachyderma in piston-cored M04-PC1A from the Korea Plateau, East Sea (Japan Sea). Comparison of oxygen isotopic record (δ18O) for peak glacial/interglacial conditions during the 250 ka reveals that paleoceanographic/paleoclimatic changes in the East Sea (Japan Sea) is slightly different from those of the Pacific and Atlantic oceans. Local environmental effects were dominated by the closure of the Korea Strait during the LGM (Last Glacial Maximum) of MIS 2.0 and MIS 6.2. At this time the East Sea (Japan Sea) becamesemi-isolated from the Pacific. Eventually, however the global influences were dominated after sufficient reconnection to the Pacific since the beginning of MIS 8.We have concluded that the foraminiferal stable isotopic records of the East Sea (Japan Sea) show that the sea was mainly salinity-controlled when itwas isolated, but temperature-controlled on account of its reconnection to the Pacific through the opening of gateway, Korea Strait.