JpGU-AGU Joint Meeting 2020

Presentation information

[E] Poster

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS15] Global climate change driven by the Southern Ocean and the Antarctic Ice Sheet

convener:Osamu Seki(Institute of Low Temperature Science, Hokkaido University), Akira Oka(Atmosphere and Ocean Research Institute, The University of Tokyo), Yoshifumi Nogi(National Institute of Polar Research), Robin Elizabeth Bell(Lamont Doherty Earth Observatory)

[MIS15-P08] Geological evidences for Cape Darnley Bottom Water in the Wild Canyon, Antarctica: Preliminary results of R/V Hakuho-maru KH-20-1 cruise

*Minoru Ikehara1, Hiroshi Sato2, Masakazu Fujii3, Keiko Takehara4 (1.Center for Advanced Marine Core Research, Kochi University, 2.Senshu University, 3.National Institute of Polar Research, 4.Soka University)

Keywords:Southern Ocean, Anatactic Bottom Water, paleoceanography, deep-sea camera

The Cape Darnley Bottom Water (CDBW) produced in the Cape Darnley polynya (CDP) descends down Wild Canyon (Ohshima et al., 2013). According to the mooring observations (Ohshima et al., 2013), significant signals of CDBW was found at the center of Wild Canyon just off the CDP. Two months after the onset of active sea-ice production, a colder, less saline, and denser signal appeared and became dominant after June. However, there are no direct evidence for sedimentary processes in the Wild Canyon. We have conducted marine geological survey in Wild Canyon during the KH-20-1 cruise by R/V Hakuho-maru in 2020 austral summer. We obtained sediment samples at two sites using multiple corer with deep-sea camera at the bottom of the Wild Canyon. For site CAD-5 (2660m water depth), small amount of sands was recovered. Based on deep-sea camera observation, sea-floor is covered by sand and rocks. Short sediment cores were recovered at the site St16 (3347 m water depth), which is located at downstream area from CAD-5. Sediments were composed of sandy silt in the canyon, and current ripple are observed on the seafloor in the canyon, which is main stream of the CDBW.