In:
The Cryosphere, Copernicus GmbH, Vol. 13, No. 7 ( 2019-07-17), p. 1959-1981
Abstract:
Abstract. Outburst floods from subglacial lakes beneath the Antarctic Ice Sheet
modulate ice-flow velocities over periods of months to years. Although
subglacial lake drainage events have been observed from
satellite-altimetric data, little is known about their role in the
long-term evolution of ice-sheet basal hydrology. Here, we
systematically map and model past water flow through an extensive area
containing over 1000 subglacial channels and 19 former lake basins exposed
on over 19 000 km2 of seafloor by the retreat of Pine Island and
Thwaites glaciers, West Antarctica. At 507 m wide and 43 m deep on average,
the channels offshore of present-day Pine Island and Thwaites glaciers
are approximately twice as deep, 3 times as wide, and cover an area over
400 times larger than the terrestrial meltwater channels comprising the
Labyrinth in the Antarctic Dry Valleys. The channels incised into bedrock
offshore of contemporary Pine Island and Thwaites glaciers would have been
capable of accommodating discharges of up to 8.8×106 m3 s−1. We suggest that the channels were formed by episodic discharges
from subglacial lakes trapped during ice-sheet advance and retreat over
multiple glacial periods. Our results document the widespread influence of
episodic subglacial drainage events during past glacial periods, in
particular beneath large ice streams similar to those that continue to
dominate contemporary ice-sheet discharge.
Type of Medium:
Online Resource
ISSN:
1994-0424
DOI:
10.5194/tc-13-1959-2019
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2019
detail.hit.zdb_id:
2393169-3
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