Physical processes in Subglacial Lake Whillans, West Antarctica: Inferences from sediment cores

WISSARD Science Team

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

The hydrologic system beneath the Antarctic Ice Sheet is thought to influence both the dynamics and distribution of fast flowing ice streams, which discharge most of the ice lost by the ice sheet. Despite considerable interest in understanding this subglacial network and its affect on ice flow, in situ observations from the ice sheet bed are exceedingly rare. Here we describe the first sediment cores recovered from an active subglacial lake. The lake, known as Subglacial Lake Whillans, is part of a broader, dynamic hydrologic network beneath the Whillans Ice Stream in West Antarctica. Even though "floods" pass through the lake, the lake floor shows no evidence of erosion or deposition by flowing water. By inference, these floods must have insufficient energy to erode or transport significant volumes of sediment coarser than silt. Consequently, water flow beneath the region is probably incapable of incising continuous channels into the bed and instead follows preexisting subglacial topography and surface slope. Sediment on the lake floor consists of till deposited during intermittent grounding of the ice stream following flood events. The fabrics within the till are weaker than those thought to develop in thick deforming beds suggesting subglacial sediment fluxes across the ice plain are currently low and unlikely to have a large stabilizing effect on the ice stream's grounding zone.

Original languageEnglish
Pages (from-to)56-63
Number of pages8
JournalEarth and Planetary Science Letters
Volume444
DOIs
StatePublished - 15 Jun 2016

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Ice
Antarctic regions
inference
lakes
sediment core
Lakes
Sediments
sediments
ice
ice stream
lake
ice sheet
beds
sediment
Electric grounding
ice flow
Antarctica
physical process
water flow
silt

Keywords

  • Antarctica
  • Glaciology
  • Ice streams
  • Subglacial access
  • Subglacial lakes

Cite this

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abstract = "The hydrologic system beneath the Antarctic Ice Sheet is thought to influence both the dynamics and distribution of fast flowing ice streams, which discharge most of the ice lost by the ice sheet. Despite considerable interest in understanding this subglacial network and its affect on ice flow, in situ observations from the ice sheet bed are exceedingly rare. Here we describe the first sediment cores recovered from an active subglacial lake. The lake, known as Subglacial Lake Whillans, is part of a broader, dynamic hydrologic network beneath the Whillans Ice Stream in West Antarctica. Even though {"}floods{"} pass through the lake, the lake floor shows no evidence of erosion or deposition by flowing water. By inference, these floods must have insufficient energy to erode or transport significant volumes of sediment coarser than silt. Consequently, water flow beneath the region is probably incapable of incising continuous channels into the bed and instead follows preexisting subglacial topography and surface slope. Sediment on the lake floor consists of till deposited during intermittent grounding of the ice stream following flood events. The fabrics within the till are weaker than those thought to develop in thick deforming beds suggesting subglacial sediment fluxes across the ice plain are currently low and unlikely to have a large stabilizing effect on the ice stream's grounding zone.",
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Physical processes in Subglacial Lake Whillans, West Antarctica : Inferences from sediment cores. / WISSARD Science Team.

In: Earth and Planetary Science Letters, Vol. 444, 15.06.2016, p. 56-63.

Research output: Contribution to journalArticle

TY - JOUR

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