[M-IS15] 南大洋・南極氷床が駆動する全球気候変動

[MIS15-P09] Boulder, cobble, pebble, and granule of continental crust rocksfrom the Wild Canyon, off Cape Darnley, East Antarctica: Preliminary results of dredged samples during KH-20-1 cruise, R/V Hakuho-maru

*佐藤 暢¹、藤井 昌和²、池原 実³、竹原 景子⁴ (1.専修大学経営学部、2.国立極地研究所 / 総合研究大学院大学、3.高知大学海洋コア総合研究センター、4.創価大学大学院)

キーワード：東南極、ケープダンレー底層水、花崗岩類、変成岩

The Cape Darnley Bottom Water (CDBW), which is produced in the Cape Darnley polynya (CDP), descends down the Wild Canyon (Ohshima et al., 2013). According to the mooring observations by Ohshima et al. (2013), significant signals of CDBW were found at the center of the 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 is no direct evidence for the transportation processes of geological materials in the Wild Canyon.

Dredge operation was performed during KH-20-1 cruise at the bottom of Wild Canyon. Approximately 170 kg of granitoid and metamorphic rocks that are consist of continental crust were recovered. They contain boulder, cobble, pebble, and granule size of granitoid and metamorphic rocks. Furthermore, they show subangular to subrounded shape. Based on deep-sea camera observation, sea-floor is covered with soft sediments and scattered boulders.

Lithology and petrological characteristics of continental crust rocks will reveal not only transportation and sedimentary processes at the Wild Canyon but also (tectonic) development history of both the Wild Canyon and East Antarctica.