Data report: bulk sediment organic matter, carbonate, and stable isotope stratigraphy from IODP Expedition 346 Site U1427 (250–530 m CCSF-D_Patched)

Abstract

Bulk sedimentary characteristics are presented from Integrated Ocean Drilling Program Site U1427, covering the depths greater than 250 m core composite depth below seafloor (CCSFD_Patched), which spans the mid-Pleistocene transition. Site U1427 is located in the southern Sea of Japan/East Sea and was drilled during Integrated Ocean Drilling Program Expedition 346. Total organic carbon ranges from 0.5 to 3.1 wt%, total nitrogen ranges from 0.04 to 0.32 wt%, and carbonate (CaCO3) contents vary between 1.3 and 25.7 wt%. The carbon isotope ratio of organic matter (δCorg) values range from −24.9‰ to −20‰. There is a broad correspondence between the geochemical parameters and the shipboard color reflectance index (b*), and this relationship becomes more pronounced from ~375 m CCSF-D_Patched upward. The b* index has been used as an indicator of glacial–interglacial cycles at Site U1427. Using this inference, the data suggest reduced marine productivity during glacials, whereas interglacials are characterized by relatively higher marine productivity. The interpretation of C/N ratios at Site U1427 may be complicated by an inorganic nitrogen component.