Organic matter contents and paleoproductivity variation within late Pleistocene Japan Sea/East Sea sediments; results from IODP Expedition 346

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http://abstractsearch.agu.org/meetings/2017/FM/PP23C-1320.html
Author(s): Black, H. D.; Anderson, W. T., Jr.
Author Affiliation(s): Primary:
Florida International University, Miami, FL, United States
Volume Title: AGU 2017 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2017; American Geophysical Union 2017 fall meeting, New Orleans, LA, Dec. 11-15, 2017. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: Inorganic and organic matter concentrations as well as the stable isotopes of nitrogen and organic carbon are presented for continuous sedimentary sequences collected during Integrated Ocean Drilling Program (IODP) Expedition 346 in the Japan Sea/East Sea in 2013. During major glacioeustatic sea level changes, the paleoceanographic conditions within the Japan Sea/East Sea widely vary due to the shallow, narrow straights connecting the sea to surrounding waters limiting an influx of oceanic currents. During glacial sea level low-stands the sea can be nearly isolated, creating a highly-stratified water column and hypoxic to anoxic bottom water conditions. Meanwhile during sea level high-stands, the Tsushima Warm Current (TWC) flows into the sea bringing warmer, nutrient-rich inputs, leading to vertical mixing and oxic conditions. This study aims to better understand the role of orbital cycling within the organic matter and stable isotope contents of these Late Pleistocene sediments. A total of 192 samples were analyzed each for %CaCO3, %TOC, δ13C, %N, and δ15N from two Expedition 346 sampling sites (U1426 and U1427) during the last ≈430,000 years and statistical analyses were completed using wavelet and time series analyses. Carbonate concentration ranges from 0-44.3%, total organic carbon 0.2 to 6.4%, δ13C -25.8 to -19.6 ppm, %N 0.04 to 0.4%, and δ15N 3.8 to 13.1 ppm. These results are well correlated with b* color values of the sediment and generally show increased productivity during interglacial periods, likely through increased vertical mixing and deepwater ventilation, when compared to glacial periods within the Japan Sea/East Sea when the sea may be partially isolated.
Year of Publication: 2017
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Cenozoic; Expedition 346; IODP Site U1426; IODP Site U1427; Integrated Ocean Drilling Program; Japan Sea; North Pacific; Northwest Pacific; Pacific Ocean; Paleoecology; Pleistocene; Productivity; Quaternary; Upper Pleistocene; West Pacific; Yamato Basin
Coordinates: N370200 N370200 E1344800 E1344759
N355755 N355756 E1342636 E1342636
Record ID: 2018074813
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