Glacial trough under Larsen Ice Shelf, Antarctic Peninsula

Valle, R.A. del; Lusky, Jorge; Roura, R.M.

doi:10.1017/s0954102098000236

Cited by 10 publications

(7 citation statements)

References 2 publications

(2 reference statements)

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“…The grounding-line troughs identified from the gravity inversion are about 20 km long by 12 km wide, with depths of 900-1050 m. These dimensions are similar to a trough in the Larsen A area just seaward of the grounding line of Drygalski Glacier (64°45’S, 60°20’W) observed in the shipboard bathymetric data (Del Valle and others, 1998; Pudsey and others, 2001) (Figs 4 and 8). Because of the low- pass filtering necessary for the inversion, the troughs may actually be slightly deeper and narrower.…”

Section: Discussionsupporting

confidence: 53%

Inversion of IceBridge gravity data for continental shelf bathymetry beneath the Larsen Ice Shelf, Antarctica

Cochran¹,

Bell²

2012

J. Glaciol.

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A possible cause for accelerated thinning and break-up of floating marine ice shelves is warming of the water in the cavity below the ice shelf. Accurate bathymetry beneath large ice shelves is crucial for developing models of the ocean circulation in the sub-ice cavities. A grid of free-air gravity data over the floating Larsen C ice shelf collected during the IceBridge 2009 Antarctic campaign was utilized to develop the first bathymetry model of the underlying continental shelf. Independent control on the continental shelf geologic structures from marine surveys was used to constrain the inversion. Depths on the continental shelf beneath the ice shelf estimated from the inversion generally range from about 350 to 650 m, but vary from <300 to >1000 m. Localized overdeepenings, 20-30 km long and 900-1000 m deep, are located in inlets just seaward of the grounding line. Submarine valleys extending seaward from the overdeepenings coalesce into two broad troughs that extend to the seaward limit of the ice shelf and appear to extend to the edge of the continental shelf. The troughs are generally at a depth of 550-700 m although the southernmost mapped trough deepens to over 1000 m near the edge of the ice shelf just south of 68° S. The combination of the newly determined bathymetry with published ice-draft determinations based on laser altimetry and radar data defines the geometry of the water-filled cavity. These newly imaged troughs provide a conduit for water to traverse the continental shelf and interact with the overlying Larsen C ice shelf and the grounding lines of the outlet glaciers.

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Section: Discussionsupporting

confidence: 53%

Inversion of IceBridge gravity data for continental shelf bathymetry beneath the Larsen Ice Shelf, Antarctica

Cochran¹,

Bell²

2012

J. Glaciol.

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“…Howat et al, 2008). Similarly, basins of glacial and non glacial origin have been located beneath ice masses in East and West Antarctica (Del Valle et al, 1998;Fricker et al, 2001;Siegert et al, 2004;Hubbard et al, 2004;Bo et al, 2009;Vaughan et al, 2006Vaughan et al, , 2007Ross et al, 2012) (Figure 4a-f) and beneath the Greenland ice sheet (e.g. at Swiss Camp; Price et al, 2008;Mottram et al, 2009).…”

Section: $ %And !And!% and ! '( " "') !mentioning

confidence: 97%

Subglacial basins: Their origin and importance in glacial systems and landscapes

Cook

Swift

2012

Earth-Science Reviews

154

174

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An overdeepened cirque basin (Blea Water, UK). (b) A trunk valley overdeepening bisected by post glacial alluvial deposition (Buttermere, UK) (photo: Rob Larkamb); (c) A formerly 'terminal' overdeepening exposed by glacier retreat; the prominent lateral moraine (left of lake) marks the Little Ice Age glacier extent (Steingletscher, Switzerland) (photo: Tino Moeller); (d) A 'terminal' overdeepening partially exposed by glacier retreat; the overdeepening is partly confined by an arcuate moraine ridge (Bagley Icefield, Alaska) (photo: Don McCully).

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“…British Antarctic Survey cruise JR48 (February-March 2000) was the first scientific sur-vey of the area formerly occupied by the Larsen-A and Prince Gustav ice shelves, though bathymetric data were available for part of the Larsen-A area (del Valle et al, 1998). Bathymetric and 3.5 kHz acoustic profiler data showed Prince Gustav Channel to be 600-800 m deep, with an acoustic drape of sediment several meters thick overlying a smooth to hummocky surface.…”

Section: Introductionmentioning

confidence: 99%

First survey of Antarctic sub–ice shelf sediments reveals mid-Holocene ice shelf retreat

Pudsey

Evans

2001

Geol

156

103

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The retreat of five small Antarctic Peninsula ice shelves in the late 20th century has been related to regional (possibly anthropogenic) climate warming. We use the record of icerafted debris (IRD) in cores to show that the Prince Gustav Channel ice shelf also retreated in mid-Holocene time. Early and late Holocene-age sediments contain IRD derived entirely from local ice drainage basins, which fed the section of ice shelf covering each site. Coretop and mid-Holocene (5-2 ka) sediments include a wider variety of rock types, recording the drift of far-traveled icebergs, which implies seasonally open water at the sites. The period when the Prince Gustav ice shelf was absent corresponds to regional climate warming deduced from other paleoenvironmental records. We infer that the recent decay cannot be viewed as an unequivocal indicator of anthropogenic climate perturbation.

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Glacial trough under Larsen Ice Shelf, Antarctic Peninsula

Cited by 10 publications

References 2 publications

Inversion of IceBridge gravity data for continental shelf bathymetry beneath the Larsen Ice Shelf, Antarctica

Inversion of IceBridge gravity data for continental shelf bathymetry beneath the Larsen Ice Shelf, Antarctica

Subglacial basins: Their origin and importance in glacial systems and landscapes

First survey of Antarctic sub–ice shelf sediments reveals mid-Holocene ice shelf retreat

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