동해퇴적물에서 생물기원 육지기원 성분: 고해양 연구를 위한 고찰

Abstract

This study examined several piston cores from the East Sea (Japan Sea) and reviewed previous works in terms of biogenic and terrigenous sediment components and the implications for paleoceanographic and paleoclimatic variations in glacial–interglacial periods. Carbonate, biogenic opal, and a minor component of organic matter comprised biogenic components of the East Sea core sediment. Biogenic carbonate and opal, in particular, showed drastic changes in glacial and interglacial periods with inverse correlation: a glacial-period increase in carbonate and interglacial-period increase in biogenic opal. The inverse correlation of the two components implies exclusive productivity changes, if the effects of dissolution and dilution were not significant. This phenomenon may also explain the succession of biogenic productivity (interglacial diatom productivity to glacial coccolith productivity) due to paleoceanographic environmental changes. Furthermore, long-term variations of biogenic components show a close relationship to orbital-scale variation in opal and suborbital variation in biogenic carbonate (Hyun et al., 2007; Kido et al., 2007). The terrigenous component of the core sediment was composed of neighboring aluminosilicate materials with minor components of aeolian dust and volcanic materials. The spatial variations of the detrital components of slope core sediments suggest, primarily, control by hemipelagic fluxes of riverine sediments. Aeolian dust fluxes, combined with Quaternary climate variation, also affected the composition of detrital components. In hemipaleagic sediment, the silt size fraction of detrital materials was mostly composed of aeolian dust, implying orbital- and millennial-scale variation (Bahk et al., 2004; Nakashima et al., 2007).