AGU Fall Meeting 2022

ANTARCTICA

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SEA LEVEL RISE

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EAIS

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TOTTEN GLACIER

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BERYLLIUM

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GRAIN SIZE

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LAST GLACIAL MAXIMA

ANTARCTICA - SEA LEVEL RISE - EAIS - TOTTEN GLACIER - BERYLLIUM - GRAIN SIZE - LAST GLACIAL MAXIMA

Totten Glacier

Melting of Totten Glacier, East Antarctica since the Last Glacial Maxima Revealed by Beryllium Isotope Ratios and Grain Size Analysis of Marine Sediment Records

Antarctica - 空より遠いところ

靜·淨·敬·鏡
安靜 Serenity
純淨 Purity
敬畏 Reverence
明鏡 Mirror
此乃南極也 This is Antarctica

#南極 #南极 #antarctica #southpole #nekoharbour #paradisebay #antarcticaexpedition

Why Antarctica matters?

CLIMATE CHANGE
- global warming —> ice sheet melting —> sea level rise
SCIENTIFIC INQUIRY
- time capsule that stores the history of our planet and the universe
GEOPOLITICS
- the only “borderless” continent that belongs to no single country because of the Antarctic Treaty, which will expire in 2048
PHILOSOPHY
- ruminate upon the human-nature relationship in the pristine land of Antarctica

BACKGROUND

How my Antarctic journey began…

a trip to the Antarctic Peninsula as an interpretation volunteer for the Antarctic Forum…

“Antarctica: In Search of the Frequency of Life”

the documentary I helped out as the Assistant to the Editor-in-Chief during the trip (in Chinese tho :p)

REGIONAL SETTING

(A)Map of Antarctica showing West and East Antarctica.

(B)Subglacial topography of the Aurora Subglacial Basin using the BEDMAP2 Elevation model (Fretwell et al., 2013). Nearby Wilkes Subglacial Basin, Ross Ice Shelf and eastward-flowing Antarctic Circumpolar Current are also indicated.

(C)Study region offshore the Sabrina Coast with seafloor multibeam bathymetry map (Armand et al., 2018), location of sediment core PC01 (yellow dot), the Totten Glacier (TG), Antarctic Slope Current (ASC) and a major gyre identified by Wakatsuchi et al., 1994 indicated.

METHODOLOGY

RESULTS

A) Beryllium-10/Beryllium-9 ratio (this study)

B) Beryllium-10 (this study)

C) Beryllium-9 (this study)

D) mean grain size (this study)

E) absolute diatom abundance (Leventer, 2020)

F) magnetic susceptibility (MS)

G) natural gamma radiation (NGR) from hole PC01

H) ice core δ18O from EPICA Dome C (Jouzel and Masson-Delmotte, 2007)

Relative 9Be vs. relative 10Be for

Offshore Sabrina Coast A (black circles, this study, ~27 to 17 ka BP); B (black squares, this study, ~17 to 9 ka BP); C: (black triangles, this study, ~9 ka BP to present)

L. Maruwan Oike and L. Skallen (pink circles and orange squares, Sproson et al., 2021a)

Offshore Wilkes Land (blue open diamonds, Valletta et al., 2018)

Offshore Adélie Land (green stars, Behrens et al., 2022).

DISCUSSION

•Minimal melting

•Perrenial sea ice

•Grounded ice sheet advance

•Weak Antarctic Slope Current (ASC)

•Some meltwater, but limited

•Stronger ASC

•Sediments from the continent ↓

•Modified Circumpolar Deepwater (mCDW) upwelling

•Meltwater

•Grounded ice retreat (basal erosion)

East Antarctica is NOT a sleeping giant
Our Be isotope data show meltwater flux from the Sabrina Coast region of East Antarctica in early Holocene ~9000 years ago, potentially caused by the Totten Glacier retreat
Antarctic Slope Current’s influence on sediment deposition along continental slope increased after the Last Glacial Maxima (from ~17000 years ago)
Core PC01 has the potential to reconstruct paleoclimates of Antarctica, and may even give insights about teleconnection with Northern Hemisphere climates
Unresolved Question: Could the Northern Hemisphere ice sheet collapse at ~8.2 ka be a trigger for the melting of Totten Glacier?

CONCLUSION