동해 퇴적물에서 생물기원물질의 변화:고해양학적 의미

Abstract

Sediments of seven piston cores from the East Sea (Japan Sea) ware analyzed to tracking evolution of paleoceanographic and paleoclimatic changes. The variation of organic carbon shows distinctive pattern between the last glacial maximum (LGM) and the Holocene. Carbonate contents are similar to those for organic carbon and also serve to distinguished pattern in Holocene from LGM sediment. Carbonate contents are significantly higher during the glacial interval in several core sediment samples exhibit a striking contrast with constant Holocene. The variations of biogenic fractions occurred between the LGM and the Holocene are related with the productivity changes, preservation, and supply changes from neighboring continent. The C/N ratio of organic matter is higher than 10 in glacial interval in several core sediments, indicating a terrigenous supply of organic carbon is responsible for the increase of biogenic fraction during the glacial period. Increased carbonate content during the glacial period is thought to relate with increase preservation, as known to previous works, however, its variation is, at least, connected with productivity changes during glacial period. Biogenic opal content also shows typical Holocene and LGM variation. Therefore, biogenic fractions (organic carbon, carbonate and biogenic opal) clearly related productivity changes. Provably local oceanographic condition was triggered these rather specific variations in biogenic fractions. Global climatic changes in terms of glacial-interglacial time scale also promote the variation of biorgnic fraction of the East Sea.