Antarctic basal environment shaped by high-pressure flow through a subglacial river system

The stability of ice sheets and their contributions to sea level are modulated by high-pressure water that lubricates the base of the ice, facilitating rapid flow into the ocean. In Antarctica, subglacial processes are poorly characterized, limiting understanding of ice-sheet flow and its sensitivit...

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Bibliographic Details
Published in:Nature Geoscience
Main Authors: Dow, C, Ross, N, Jeofry, H, Siu, K, Siegert, M
Format: Article in Journal/Newspaper
Language:unknown
Published: Nature Research 2022
Subjects:
Science & Technology
Physical Sciences
Geosciences
Multidisciplinary
Geology
WEDDELL SEA SECTOR
ICE SHELF CAVITY
GROUNDING LINE
SHEET MODEL
WATER
DRAINAGE
CHANNEL
BENEATH
MELT
MELTWATER
Meteorology & Atmospheric Sciences
Antarctic
Weddell
Weddell Sea
Antarc*
Antarctica
Ice Sheet
Ice Shelf
Online Access:http://hdl.handle.net/10044/1/100663
https://doi.org/10.1038/s41561-022-01059-1
Description
Summary:The stability of ice sheets and their contributions to sea level are modulated by high-pressure water that lubricates the base of the ice, facilitating rapid flow into the ocean. In Antarctica, subglacial processes are poorly characterized, limiting understanding of ice-sheet flow and its sensitivity to climate forcing. Here, using numerical modelling and geophysical data, we provide evidence of extensive, up to 460 km long, dendritically organized subglacial hydrological systems that stretch from the ice-sheet interior to the grounded margin. We show that these channels transport large fluxes (~24 m3 s−1) of freshwater at high pressure, potentially facilitating enhanced ice flow above. The water exits the ice sheet at specific locations, appearing to drive ice-shelf melting in these areas critical for ice-sheet stability. Changes in subglacial channel size can affect the water depth and pressure of the surrounding drainage system up to 100 km either side of the primary channel. Our results demonstrate the importance of incorporating catchment-scale basal hydrology in calculations of ice-sheet flow and in assessments of ice-shelf melt at grounding zones. Thus, understanding how marginal regions of Antarctica operate, and may change in the future, requires knowledge of processes acting within, and initiating from, the ice-sheet interior.

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