Résumé
Organic matter concentrations and organic carbon and nitrogen isotopes are reported for sediments drilled during Integrated Ocean Drilling Program Expedition 346. The Japan Sea/East Sea sediments from Sites U1426 and U1427 feature a range of total organic carbon (%TOC) between 0.16% and 6.36%, total nitrogen (%N) between 0.04% and 0.39%, delta (super 13) C values between -25.87ppm and -19.56ppm, delta (super 15) N values between 3.33ppm and 13.08ppm, and carbonate concentrations (%CaCO (sub 3) ) between 0% and 44.29%. The East China Sea sediments from Site U1429 feature a range of %TOC between 0.10% and 2.85%, %N between 0.02% and 1.22%, delta (super 13) C values between -24.74ppm and 17.73ppm, delta (super 15) N values between 3.59ppm and 13.40ppm, and %CaCO (sub 3) between 0.70% and 42.84%. Both organic matter content and stable isotopes are well correlated with b* sediment color reflectance values and infer decreased surface productivity and suboxic to anoxic environments during glacial periods and increased productivity and deep-water ventilation during interglacial periods in the Japan Sea/East Sea.