Biogenic sedimentation patterns in the northern South China Sea: An ultrahigh-resolution record MD972148 of the past 150,000 years from the IMAGES III-IPHIS cruise
Ultrahigh resolution records of carbonate and organic carbon concentrations from core MD972148 (19 degrees 47.804'N 117 degrees 32.56'E; water depth 2830 m) provide information on glacial-interglacial as well as millennial to centennial scale variability in the production of biogenic sediments in the northern slope of the South China Sea (SCS) over the past 150,000 years. A preliminary age model of this record is estimated using a biostratigraphic datum of Globigerinoides ruber (pink) and the relationship of carbonate concentrations and partial derivative(18)O of planktonic foraminifers shown in previous SCS records. The downcore patterns in this record show that the carbonate concentration maxima correspond to interglacial times and minima correspond to glacials, indicating effects of dilution of terrengious clastic sediments from nearby continents. Exposure of extensive continental shelf and relatively dry climate during glacial periods are responsible for the enhanced input of terrengious components into the SCS. Two long-term trends in which the organic carbon content was increased steadily from stage 5 to stage 2 and from the late stage 7 to stage 6 are clearly observed. High organic carbon concentrations seem to occur during the transition from major glacial to interglacial stages and are probably controlled by effects of preservation or rates of sedimentation, or biological productivity. We have also observed significant components of high-frequency variability in the carbonate and organic carbon concentration records. These rapid concentration changes can be attributed possibly to highly-unstable climatic conditions in the SCS during the late Quaternary.
Keyword(s)
paleoceanography, late Quaternary, carbonate sedimentology, South China Sea
Chen YY, Chen MT, Fang TS (1999). Biogenic sedimentation patterns in the northern South China Sea: An ultrahigh-resolution record MD972148 of the past 150,000 years from the IMAGES III-IPHIS cruise. Terrestrial Atmospheric And Oceanic Sciences. 10 (1). 215-224. https://archimer.ifremer.fr/doc/00239/35072/