Ice stream sticky spots: A review of their identification and influence beneath contemporary and palaeo-ice streams

Stokes, Chris R.; Clark, Chris D.; Lian, Olav B.; Tulaczyk, S. M.

doi:10.1016/j.earscirev.2007.01.002

Cited by 140 publications

(123 citation statements)

References 137 publications

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“…Consequently, from the complexity of the inner shelf geology and its bedform assemblages, we also infer a complicated palaeo-flow regime, consisting of shallow deformation and sliding over water and sediment. The rough, undulating topography of the inner shelf probably favoured locally higher basal shear stresses causing a patchwork of areas with sliding over bare rock zones (i.e., localised regions of higher basal drag, such as sticky spots, Stokes et al, 2007) and areas with enhanced deformation or sliding where 'stick-slip' processes dominated. Zones of smoother, subdued seabed, interspersing lineations and drumlins on the inner shelf (e.g.…”

Section: Multi-temporal Record Of Flow and Substrate Controls On Bedfmentioning

confidence: 99%

Bedform signature of a West Antarctic palaeo-ice stream reveals a multi-temporal record of flow and substrate control

Graham

Larter

Gohl

et al. 2009

Quaternary Science Reviews

174

173

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a b s t r a c tThe presence of a complex bedform arrangement on the sea floor of the continental shelf in the western Amundsen Sea Embayment, West Antarctica, indicates a multi-temporal record of flow related to the activity of one or more ice streams in the past. Mapping and division of the bedforms into distinct landform assemblages reveals their time-transgressive history, which implies that bedforms can neither be considered part of a single downflow continuum nor a direct proxy for palaeo-ice velocity, as suggested previously. A main control on the bedform imprint is the geology of the shelf, which is divided broadly between rough bedrock on the inner shelf, and smooth, dipping sedimentary strata on the middle to outer shelf. Inner shelf bedform variability is well preserved, revealing information about local, complex basal ice conditions, meltwater flow, and ice dynamics over time. These details, which are not apparent at the scale of regional morphological studies, indicate that past ice streams flowed across the entire shelf at times, and often had onset zones that lay within the interior of the Antarctic Ice Sheet today. In contrast, highly elongated subglacial bedforms on sedimentary strata of the middle to outer shelf represent a timeslice snapshot of the last activity of ice stream flow, and may be a truer representation of fast palaeo-ice flow in these locations. A revised model for ice streams on the shelf captures complicated multi-temporal bedform patterns associated with an Antarctic palaeo-ice stream for the first time, and confirms a strong substrate control on a major ice stream system that drained the West Antarctic Ice Sheet during the Late Quaternary.

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Section: Multi-temporal Record Of Flow and Substrate Controls On Bedfmentioning

confidence: 99%

Bedform signature of a West Antarctic palaeo-ice stream reveals a multi-temporal record of flow and substrate control

Graham

Larter

Gohl

et al. 2009

Quaternary Science Reviews

174

173

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“…Understanding the behaviour of subglacial meltwater systems is crucial because of their influence upon substrate rheology and ice-bed coupling (Boulton & Hindmarsh, 1987;Iverson et al, 1995;Boulton, 1996;Piotrowski et al, 2004Piotrowski et al, , 2006Evans et al, 2006;Kjaer et al, 2006;Lee & Phillips, 2008;Boulton et al, 2009), and in-turn, glacier dynamics that operate over a range of temporal and spatial scales (Kamb, 1987;Bartholomew et al, 2010;Sundal et al, 2011;Robel et al, 2013). Research now recognises that these processes act to drive the expansion, break-up and collapse of major ice streams and ice masses (MacAyeal, 1993;Clark, 1994;Tulaczyk et al, 2000;Bell et al, 2007;Stokes et al, 2007;Burke et al, 2012) thus linking subglacial drainage to collapsing ice masses, sea-level change and abrupt climate change (Goezler et al, 2011;King et al, 2012;Hanna et al, 2013;Fürst et al, 2014 and references therein). Indeed, subglacial meltwater systems underpin major global issues surrounding the stability of the modern Antarctic and Greenland ice sheets, their sensitivity too and influence on current and future changes in sea-level and climate (Alley et al, 2005;Zwally et al, 2005;Shepherd & Wingham, 2007;Pfeffer et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Lee

Wakefield

Phillips

et al. 2015

Quaternary Science Reviews

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Subglacial drainage systems exert a major control on basal-sliding rates and glacier dynamics. However, comparatively few studies have examined the sedimentary record of subglacial drainage. This is due to the paucity of modern analogues, the limited recognition and preservation of upper flow regime deposits within the geological record, and the difficulty of distinguishing subglacial meltwater deposits from other meltwater sediments (e.g. glacier outburst flood deposits). Within this study, the sedimentological and structural evolution of a subglacial to subaerial (ice-marginal / proglacial) drainage system is examined. Particular emphasis is placed upon the genetic development and preservation of upper flow regime bedforms and specifically recognising them within a subglacial meltwater context. Facies attributed to subglacial meltwater activity record sedimentation within a confined, but progressively enlargening, subglacial channel system produced under dune to upper flow regime conditions. Bedforms include rare large-scale sinusoidal bedding with syn-depositional deformation produced by current-induced traction and shearing within the channel margins. Subglacial sedimentation culminated with the abrupt change to a more ephemeral drainage regime indicating channel-abandonment or a seasonal drainage regime. Retreat of the ice margin, led to the establishment of subaerial drainage with phases of sheet-flow punctuated by channel incision and anastomosing channel development under diurnal, ablation-related, seasonal discharge. The presence of extensive hydrofracture networks demonstrate that proglacial groundwater-levels fluctuated markedly and this may have influenced later overriding of the site by an ice stream.

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“…Prior to the 1980s, most subglacial tills were assumed to be formed by lodgement, a frictional process. However, once the importance of pore-water pressure on subglacial processes was demonstrated (Boulton and Jones, 1979;Alley et al, 1986;Clarke, 1987), it was suggested that lodgement and deformation till were actually part of a pore-water pressure continuum (Brown et al, 1987;Hart and Boulton, 1991;Hicock, 1992;Hicock and Dreimanis, 1992;Iverson et al, 1995), which varies temporally and spatially in the form of mobile beds and sticky spots (Alley, 1993;Piotrowski et al, 2004;Stokes et al, 2007Stokes et al, , 2009Smith and Murray, 2009). Deformation within this layer has been modelled as a shear zone (Hart and Boulton, 1991;Scherer et al, 2004;van der Meer et al, 2003;Lee and Phillips, 2008).…”

Section: Introductionmentioning

confidence: 99%

Subglacial till behaviour derived from in situ wireless multi-sensor subglacial probes: Rheology, hydro-mechanical interactions and till formation

Hart

Rose

Martinez

2011

Quaternary Science Reviews

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Ice stream sticky spots: A review of their identification and influence beneath contemporary and palaeo-ice streams

Cited by 140 publications

References 137 publications

Bedform signature of a West Antarctic palaeo-ice stream reveals a multi-temporal record of flow and substrate control

Bedform signature of a West Antarctic palaeo-ice stream reveals a multi-temporal record of flow and substrate control

Sedimentary and structural evolution of a relict subglacial to subaerial drainage system and its hydrogeological implications: an example from Anglesey, north Wales, UK

Subglacial till behaviour derived from in situ wireless multi-sensor subglacial probes: Rheology, hydro-mechanical interactions and till formation

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