Ice stream motion facilitated by a shallow-deforming and accreting bed

Spagnolo, Matteo; Phillips, Emrys; Piotrowski, Jan A.; Rea, Brice R.; Clark, Chris D.; Stokes, Chris R.; Carr, Simon; Ely, Jeremy C.; Ribolini, Adriano; Wysota, Wojciech; Szuman, Izabela

doi:10.1038/ncomms10723

Cited by 72 publications

(59 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Canals et al 2000;Spagnolo et al 2014), and a number of theories exist concerning the detailed mechanisms by which they form (e.g. Hindmarsh 1999;Clark et al 2003;Schoof & Clarke 2008;Spagnolo et al 2016). These elongate subglacial landforms are often distinguished on the basis of their absolute size and elongation ratio (the ratio between their maximum length and width).…”

Section: Subglacial Landformsmentioning

confidence: 99%

The variety and distribution of submarine glacial landforms and implications for ice-sheet reconstruction

Dowdeswell

Canals

Jakobsson

et al. 2016

Memoirs

View full text Add to dashboard Cite

Glacimarine processes affect about 20% of the global ocean today, and this area expanded considerably under cyclical full-glacial conditions during the Quaternary (Fig. 1) . Many of the submarine landforms produced at the base and margin of past ice sheets remain well preserved on the seafloor in fjords and on high-latitude continental shelves after the retreat of the ice that produced them. These glacial landforms, protected from subaerial erosion and beneath wave-base and tidal currents in water that is often hundreds of metres deep, are gradually buried by both hemipelagic and glacimarine sedimentation; they may be preserved over long periods in the geological record if palaeocontinental shelves are not reworked by subsequent glacier advances or bottom currents ). This means that, first, submarine glacial landforms can be observed at or close to the modern seafloor after retreat of the last great ice sheets from their most recent Quaternary maximum about 18-20 000 years ago using swath-bathymetric mapping systems and, secondly, buried glacial landforms may also be identified and examined within glacial-sedimentary sequences from Quaternary and earlier ice ages using seismic-reflection methods.The development of multibeam echo sounding over the past two decades, coupled with high-accuracy GPS positioning, has allowed morphological mapping of the seafloor at an unprecedented level of detail. In this paper, the variety of submarine glacial landforms observed in modern, Quaternary and more ancient sediments is described. Landforms produced subglacially, those formed at and beyond marine ice-sheet margins, together with the slope processes and bottom currents likely to result in their reworking, are considered along with the sediment volumes of these landforms and the time they take to develop. This is followed by discussion of the significance of submarine glacial landforms and landform-assemblages for reconstruction of the form and flow of past ice sheets, including the former extent and flow direction of ice sheets, whether they are flowing fast as ice streams or slowly in inter-ice stream areas, the nature and rate of ice-sheet deglaciation, conditions at past ice-sheet beds, and inferences on the characteristics of the basal hydrological system and past climatic conditions.

show abstract

Section: Subglacial Landformsmentioning

confidence: 99%

The variety and distribution of submarine glacial landforms and implications for ice-sheet reconstruction

Dowdeswell

Canals

Jakobsson

et al. 2016

Memoirs

View full text Add to dashboard Cite

show abstract

“…Studying the nature of palaeo-ice 30 sheets and the factors which contribute to their demise is important with regard to understanding the dynamics of contemporary ice sheets and predicting their response to future climate change (Golledge et al, 2015;Pollard and DeConto, 2009;Ritz et al, 2015;Stokes et al, 2015). The stability of both former and contemporary marine-based ice sheets is primarily controlled by the discharge of the ice-mass through ice streams, and understanding their behaviour is of critical importance (Jamieson et al, 2012;King et al, 2009;Spagnolo et al, 2016;. Reconstructing palaeo-ice stream behaviour and their influence on deglaciation provides a long-term perspective of such processes and, as such, can provide insight into dynamic changes that might be expected in contemporary ice sheets and how they might impact on sea level.…”

Section: Introductionmentioning

confidence: 99%

Reconstructing the retreat dynamics of the Bjørnøyrenna Ice Stream based on new 3D seismic data from the central Barents Sea

Piasecka

Winsborrow

Andreassen

et al. 2016

Quaternary Science Reviews

Self Cite

View full text Add to dashboard Cite

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. 20Our results reveal major changes in the configuration and flow dynamics of the ice stream, with up to 10 flow-switching events identified. For the first time, we also document ice streaming sourced from the eastern Barents Sea around the time of the LGM. This high degree of flow variability is suggested to have resulted from climate-driven changes in ice sheet geometry (and ice divide migration), and variations in topography that influenced calving at the ice stream terminus.2

show abstract

“…Turning to the finer, sub-km morphological character of each site, detailed ground-based radar surveys of PIG's trunk (Figs. 2 and 3, and see further imagery in Bingham et al, 2017) have depicted ubiquitous mega-scale glacial lineations (MSGL) across all regions of PIG's trunk, indicative of the widespread presence of deforming sediment (Clark, 1993;Stokes and Clark, 2001;Spagnolo et al, 2016). MSGL with mean amplitudes ∼ 10 m and a mode spacing of 300-400 m are also pervasive surrounding the RIS repeat survey site (Fig.…”

Section: Are Ice-stream Beds Dynamic?mentioning

confidence: 99%

How dynamic are ice-stream beds?

et al. 2018

Self Cite

View full text Add to dashboard Cite

Abstract. Projections of sea-level rise contributions from West Antarctica's dynamically thinning ice streams contain high uncertainty because some of the key processes involved are extremely challenging to observe. An especially poorly observed parameter is sub-decadal stability of ice-stream beds, which may be important for subglacial traction, till continuity and landform development. Only two previous studies have made repeated geophysical measurements of ice-stream beds at the same locations in different years, but both studies were limited in spatial extent. Here, we present the results from repeat radar measurements of the bed of Pine Island Glacier, West Antarctica, conducted 3-6 years apart, along a cumulative ∼ 60 km of profiles. Analysis of the correlation of bed picks between repeat surveys shows that 90 % of the bed displays no significant change despite the glacier increasing in speed by up to 40 % over the last decade. We attribute the negligible detection of morphological change at the bed of Pine Island Glacier to the ubiquitous presence of a deforming till layer, wherein sediment transport is in steady state, such that sediment is transported along the basal interface without inducing morphological change to the radarsounded basal interface. Given the precision of our measurements, the upper limit of subglacial erosion observed here is 500 mm a −1 , far exceeding erosion rates reported for glacial settings from proglacial sediment yields, but substantially below subglacial erosion rates of 1.0 m a −1 previously reported from repeat geophysical surveys in West Antarctica.

show abstract

Ice stream motion facilitated by a shallow-deforming and accreting bed

Cited by 72 publications

References 46 publications

The variety and distribution of submarine glacial landforms and implications for ice-sheet reconstruction

The variety and distribution of submarine glacial landforms and implications for ice-sheet reconstruction

Reconstructing the retreat dynamics of the Bjørnøyrenna Ice Stream based on new 3D seismic data from the central Barents Sea

How dynamic are ice-stream beds?

Contact Info

Product

Resources

About