R O S S S E A

Post-LGM evolution of Reedy Glacier, Antarctica, as an indicator of current ice sheet stability

Gordon Bromley, Brenda Hall, Claire Todd, John Stone, Howard Conway, Maurice Conway

ROSS SEA

W A I S

E A I S

Terra Nova Bay c. 7800 yr BP

McMurdo Sound c. 7400 yr BP

Hatherton Glacier c. 6800 yr BP

Roosevelt Island c. 3200 yr BP

ROSS SEA

W A I S

Terra Nova Bay c. 7800 yr BP

McMurdo Sound c. 7400 yr BP

Hatherton Glacier c. 6800 yr BP

Roosevelt Island c. 3200 yr BP

E A I S

Reedy Glacier, 86˚S

WAIS

EAIS

Downglacier (north-west) from Quartz Hills, 85˚56’S

Watson Escarpment from Caloplaca Hills, 86˚07’S

Hypotheses

2) Modern instability of Reedy Glacier suggests ongoing recession of Ross Sea grounding line

1) Stabilisation of Reedy Glacier during the Holocene suggests stability of Ross Sea grounding line

Hatcher Bluff: 40 m

Polygon Spur: 40-90 m

Caloplaca Hills: 150 m

Quartz Hills: 300 m

Cohen Nunatak: >110 m

E A I S

Langford Peak: >110 m

Shapley Ridge: 40 m

Metavolcanic Mtn: 40 m

Strickland Nunatak: 40 m

Reedy III drift (LGM) overlying old surface, Quartz Hills

W A I SPre-LGM deposits, Quartz Hills

Surficial geology and geomorphology of Polygon Spur, Reedy Glacier

Surficial geology and geomorphology of Quartz Hills

Present and former surface profiles of Reedy Glacier

• Glacial deposits have allowed reconstruction of Reedy Glacier at the LGM

• WAIS was c. 600 m thicker at the LGM than at present