Ice-core-dated englacial stratigraphy across Wilkes Subglacial Basin, East Antarctica: Implications for ice-sheet behaviour

Abstract

Wilkes Subglacial Basin (WSB) stores enough ice to raise global sea levels by three to four metres, and comprises a region of East Antarctica potentially vulnerable to climate-induced ice loss. We investigate WSB’s glacial history back to just after the Last Interglacial (

130–115 ka) using its englacial stratigraphy. We trace eight radio-echo-sounded internal reflection horizons (IRHs) across WSB, dating them at intersections with Talos Dome and EPICA Dome C ice cores, with one IRH englacially connecting the ice cores. The WSB IRHs span ages from 13.1

plus or minus $\pm$ ±

0.5 to 90.3

plus or minus $\pm$ ±

2.3 ka, with an older 122.5

plus or minus $\pm$ ±

2.0 ka IRH traced across the Dome C plateau. With these IRHs, we make regional inferences about past and present ice behaviour, including identifying areas of IRH drawdown relating to ice velocity, accumulation and geothermal heat flow. Approximately 300 km upstream of the WSB grounding line, 20

percent sign $\%$ %

of the ice lies below and hence is older than 90.3

plus or minus $\pm$ ±

2.3 ka, suggesting ice presence across this region throughout the Last Interglacial. Several of our IRHs have been mapped extensively elsewhere across the East Antarctic Ice Sheet, and this study therefore contributes to the wider objective of mapping Antarctica-wide englacial stratigraphy.