Details of PC1608 sediment core recovered from 437 meter depth off Wakasa Bay in the Sea of Japan

Description

PC1608 is 734 cm long sediment core recovered at N36˚26.1086’, E135˚ 07.8319’. It was obtained using an 8 m piston corer during the UT16 cruise (July to August, 2016) of the research and training vessel Umitaka-maru of the Tokyo University of Marine Science and Technology. Two 4 m long PVC liners were loaded. After core recovery, these liners were extruded from a stainless outer pipe, sectioned into ~1 m, then split lengthwise on the deck. After onboard core descriptions from the split surfaces, these half round sediments were packed as working- and archive-halves, and stored in the refrigerator for further onshore work. The archive-half was cut 50 cm from the section top, then transported to the Kochi Core Center for obtaining radiograph and CT scan image using the GE Healthcare LightSpeed Ultra 16. Work at Kochi Core Center was conducted under the cooperative research program of the Center for Advanced Marine Core Research (CMCR), Kochi University (Accept No. 16B071 and 17A061). For early sediment age estimations from diatom assemblages, part of sediments collected by cut-off 2.5 ml disposable syringe were used. Preparation of the smear slides and the counting procedure followed Akiba (1986) and Akiba et al. (2014). The sediment suspensions were made in hot water without any chemical treatments or the use of a dispersing agent. The coarse and dense particles in the suspension were allowed to settle and excluded from slide mounting procedure. The microscope viewing area was moved along virtual grid lines until 100 diatom tests were identified. The total diatom abundance in a slide was estimated from the line lengths. The sediment samples for foraminiferal study were wet-sieved without freeze drying. A 180 µm sieve was used. The sieved residues were transported onto filter paper, rinsed by spraying distilled water, and then air-dried. The air-dried particles were dry-sieved with a 250 µm sieve. Planktonic foraminiferal tests for radio 14C measurements were mainly collected from particles larger than 250 µm for more than 10 mg. The 14C ages of planktonic foraminiferal tests were determined using the accelerator mass spectrometry (AMS) at the Institute of Accelerator Analysis, Ltd. (http://www.iaa-ams.co.jp/indexen.html). After acid cleaning (~30 % of sample was removed), gaseous CO2 was evolved from the CaCO3 with phosphoric acid and then reduced to graphite. The graphite 13C was also determined by the AMS for calibrating the 14C data. The calendar ages were calculated from the Marine 13 data base (Reimer et al., 2013) and the OxCalv4.2 program (Bronk Ramsey, 2009). Local variations in marine reservoir effect were not considered (R = 0). Upload References (References_PC1608.pdf) Location of PC1608 coring site (Coring site_PC1608.pdf) Law data of CT scan (DICOM_PC1608) Diatom assemblage (Diatom_PC1608.xlsx) Planktonic foraminiferal test 14C (14C age_PC1608.xlsx) Radiograph (Radiograph_PC1608.pdf) Data summary (Data summary_PC1608.pdf)

Institutions

• Meiji Daigaku

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