Patagonia at LGM
Glacial LGM limit
NPISPI Polar Front
SB of
ACC
SHW
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EDML Scotia Sea
Patagonia
East Antarctica SW Atlantic
Antarctic Peninsula
West Antarctica
Pirie Basin
BasinDove
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sea i ce
PS cores
Iceberg Alley
Weddell Sea Winter sea ice
Drake Passage
Summer
Filchner-Rønne Ice Shelf
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45°S
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65°
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WSDW ACC
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Filchner-Rønne Ice Shelf
Amery Ice Shelf
Antarctic Coastal Current
ACC
Antarctic Coastal Current
SCO-13 SCO-14 SCO-21
SFSD-01A SFSD-02A
SCO-17 SCO-11
A
The role of warm oceans in past Antarctic ice-sheet variability. New drilling with IODP Expedition 382
Frida S. Hoem
1, Henk Brinkhuis
1,3, Francesca Sangiorgi
1, Francien Peterse
2and Peter K. Bijl
11Marine Palynology and Paleoceanography, 2Organic geochemistry, Department of Earth Sciences, Utrecht University, Princetonlaan 8A, Utrecht, The Netherlands,
3Royal Netherlands Institute for Sea Research (NIOZ)
The Antarctic Ice Sheet (AIS) may be highly sensitive to future ocean-driven warming due to excessive subsurface melting, and conse- quential multi-meter rise in sea level. Studying the evolution and sensi- tivity of ocean-ice-climate interactions under past analogue climate conditions in the Southern Ocean, will be critical for future sea level rise projections.
International Ocean Discovery Program (IODP) Expedition 382, Iceberg Alley and Subantarctic Ice and Ocean Dynamics, will investigate how the coupled Antarctic ice-ocean-climate system evolved to the present state and how it behaved across major climate transitions in the past and par- ticularly during warmer-than-present times. The aim is to drill six sites of Neogene (past 23 million years) sediments in the Scotia Sea (Figure 1), east of the Antarctic Peninsula, providing the first deep (900m) drilling in this important region of the Southern Ocean.
Contact:
f.s.hoem@uu.nl +4799464023
Miocene Olig. latelmiddleearlyNeogene EpochPeriod Quat. Pleist.
Pliocene
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Lisiecki and Raymo (2005)
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Figure 2. Seismic stratigraphy and associated ice sheet and climate events. Weber, M.E., Raymo, M.E., Peck, V.L., and Williams, T., 2018. Expedition 382 Scientific Prospectus.
References:
DeConto, R.M., and Pollard, D., 2016. Contribution of Antarctica to past and future sea-level rise. Nature, 531(7596):591–597.
Lindeque, A., Martos, Y.M., Gohl, K., and Maldonado, A., 2013. Deep-sea pre- glacial to glacial sedimentation in the Weddell Sea and southern Scotia Sea from a cross-basin seismic transect. Marine Geology, 336;61–83.
Zachos, J., Pagani, M., Sloan, L., Thomas, E., and Billups, K., 2001. Trends, rhythms, and aberrations in global climate 65 Ma to present. Science, 292(5517):686–693.
Weber, M.E., Clark, P.U., Kuhn, G., Timmermann, A., Sprenk, D., Gladstone, R., Zhang, X., et al., 2014. Millennial-scale variability in Antarctic ice- sheet discharge during the last deglaciation. Nature, 510(7503):134–138.
Weber, M.E., Raymo, M.E., Peck, V.L., and Williams, T., 2018. Expedition 382 Scientific Prospectus: Iceberg Alley and South Falkland Slope Ice and Ocean Dynamics. International Ocean Discovery Program.
Sailing as a palynologist from Punta Arenas, Chile, 20. March – 20. May 2019, I aim to provide crucial shipboard age control using organic-walled dinoflagellate cyst (dinocyst) assemblages. Shore based I will employ the (recent) advances in Paleogene and Neogene dinocyst stratigraphy and pal- eoecology to assist in reconstructing long term Antarctic ice-sheet fluctua- tions, sea-ice cover, surface-ocean primary productivity, temperatures, ocean circulation through the Drake Passage, and changes in oceanic and atmos- pheric fronts in the vicinity of the ACC. Results will be paired with bio- marker analysis for absolute temperatures.
Figure 1: Map of the central Scotia Sea with proposed drilling sites (yellow dots). Open blue arrows indicate iceberg pathways drifting out of the Weddell Sea. Insert shows circum-Antarctic drift of icebergs calving off the Antarctic ice shelves (1999–2009) (Stuart and Long, 2011). Black arrows = general counterclockwise flow in the ACC. Figure modified from Weber et al. (2014).
New Zealand
Australia East Antarctica
West
Antarctica
Ross Sea South America
1165 696
U1356
Prydz Bay Weddell Sea
1168
CRP 269
U1521
U1508/1509 274
Exp.382
In my PhD project; The role of warm oceans in the past Antarctic ice-sheet variability, I will;
(re)examine ODP/IODP sedimentary cores from the broader circum-Antarctic region (see map) to extrapolate the pilot palynological results to other regions of the Southern Ocean.
Couple results with organic geochemical biomarker analysis for absolute sea surface temperature reconstructions (e.g, TEX86, Uk,37).
The regional spread of oceanographic reconstructions will yield a circum-Antarctic- wide view on past ice-proximal ocean conditions crucial for more realistic ice sheet model simulations which are ultimately used to predict future sea level rise.
