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-P23] Antarctic ice sheet dynamics during the Last Interglacial

*Mutsumi Iizuka1, Osamu Seki1, Keiji Horikawa3, Tina van de Flierdt2, Tomohisa Irino1, Masanobu Yamamoto1, Takuya Itaki4, Saiko Sugisaki4, Minoru Ikehara5, Yusuke Suganuma6 (1.Hokkaido university, 2.Imperial College London, 3.University of Toyama, 4.Geological Survey of Japan, 5.Center for Advanced Marine Core Research, Kochi University, 6.National Institute of Polar Research)

Keywords:Antarctic Ice Sheet, Last interglacial, Nd isotope

Ongoing global warming could cause various problems in the future. One of the serious concerns

potentially caused by the global warming is a sea level rise due to the melting of ice sheet. Antarctic

ice sheet, which hold a massive amount of fresh water, was considered to be stable even if global

warming progresses in a future. However, recent studies have shown that Antarctic ice sheet is more

sensitive to global warming than previously thought. Therefore, it is an important to better understand

extent to which Antarctic ice sheet sensitive to global warming.

Study of past warm period provides a useful insight into the prediction of sea level rise in a future.

In particular, the last interglacial (MIS 5e), which was ~1°C warmer than that of the preindustrial, is

receiving increased attention, since sea level in the period is estimated to be several meters higher than

that of the present. This suggests substantial loss of Antarctic ice sheet during MIS 5e. However,

variability of Antarctic ice sheet during MIS 5e has been poorly understood. In this study, we generate

high resolution records of mineral composition, Nd isotope and iceberg rafted debris (IBRD) in

GC1407 collected from near the Wilkes Basin, East Antarctica (130.518°E, 63.74°S) in order to better

understand Antarctic ice sheet dynamics during the warmer than the present climate condition.

The two episodic IBRD increase events are found to be recognized during MIS 5e in GC1407,

suggesting that increases in icebergs transport occurred during MIS 5e. Nd isotope and mineral

composition records in GC1407 suggest that icebergs originated from area with relatively higher eNd,

possibly either Wilkes Land Basin or West Antarctica ice sheets. The iceberg discharge events

happened when Antarctic air temperature was warmer than that of preindustrial era, suggesting a link

between Antarctic warming and increase in iceberg discharge. Furthermore, the timings of iceberg

discharge events are simultaneous with the onsets of sea level rises estimated from geological record

in Western Australia. The correspondence between the sea level and Antarctic ice sheet records

suggests substantial contribution of Antarctic ice mass loss to the sea level rises during MIS 5e.