Ice shelf grounding zone features of western Prydz Bay, Antarctica: sedimentary processes from seismic and sidescan images

O'Brien, P. E.; Santis, Laura De; Harris, Peter T.; Domack, Eugene W.; Quilty, Patrick G.

doi:10.1017/s0954102099000115

Cited by 61 publications

(47 citation statements)

References 32 publications

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“…Larter et al (2009) summarised that the shelf downflow of the bedforms mapped in our dataset lacks significant ice marginal geomorphology (e.g. large moraines or GZWs; see O'Brien et al, 1999;Shipp et al, 1999). In an ice stream deforming bed system operating as a sediment conveyer, till accumulation would be expected at the terminal position of the ice stream (Alley et al, 1989).…”

Section: Reconstruction Of Palaeo-ice Stream Flowmentioning

confidence: 94%

“…In TOPAS profiles, they appear acoustically-transparent with locally discernable bases, suggesting their composition of homogenous sediment rather than bedrock (Fig. S3) O'Brien et al, 1999).…”

Section: Inner To Middle Shelfmentioning

confidence: 99%

“…If these features are younger than many of the bedrock lineations and the MSGLs mapped elsewhere on the shelf, then they must relate to the last deglaciation accordingly. The GZWs comprise stand-alone bodies of till advected to the ice margin, or form the downstreamfacing ramp of more extensive till sheets (O'Brien et al, 1999;Shipp et al, 1999;Larter and Vanneste, 1995). The sediments required for their formation during the deglaciation may have been supplied by erosion of bedrock bedforms on the inner shelf, suggesting further time-transgressive modification of landsystem 1.…”

Section: Landsystems 4 and 5 -Ice Marginal And Pro-marginal Assemblagesmentioning

confidence: 99%

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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

172

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: Reconstruction Of Palaeo-ice Stream Flowmentioning

confidence: 94%

Section: Inner To Middle Shelfmentioning

confidence: 99%

Section: Landsystems 4 and 5 -Ice Marginal And Pro-marginal Assemblagesmentioning

confidence: 99%

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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

172

173

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“…Kellogg et al 1979; Anderson et al 1980; Orheim & 118 Elverhøi, 1981;Domack, 1982;Haase, 1986;Kennedy & Anderson, 1989 Pudsey et al 1994;Larter & Vanneste, 1995;O'Brien et al 1999;Shipp et al 1999; Canals 123 et al 2000 Canals 123 et al , 2002 Canals 123 et al , 2003Anderson & Shipp, 2001;Wellner et al 2001;Ó Cofaigh et al 2002 Ó Cofaigh et al , 124 2003 Ó Cofaigh et al , 2005a Lowe & Anderson, 2003; Dowdeswell et al 2004a,b;Evans et al 2004Evans et al , 2005 recently been demonstrated (Padman et al, 2010).…”

mentioning

confidence: 99%

Antarctic palaeo-ice streams

Livingstone

Cofaigh

Stokes

et al. 2012

Earth-Science Reviews

175

183

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We review the geomorphological, sedimentological and chronological evidence for palaeo- palaeo-ice streams to be classified into discrete retreat styles and the controls on grounding-21 line retreat to be investigated. Such analysis highlights the important impact of internal 22 factors on ice stream dynamics, such as bed characteristics and slope, and drainage basin size. 23Whilst grounding-line retreat may be triggered, and to some extent paced, by external 24 (atmospheric and oceanic) forcing, the individual characteristics of each ice stream will 25 modulate the precise timing and rate of retreat through time. ). The ability to directly observe the beds of palaeo-ice streams has also allowed 65 scientists to glean important spatial and temporal information on the processes that occurred 66 at the ice-bed interface and on the evolution of palaeo-ice streams throughout their glacial 67 history. 68Over the last two decades, there has been a burgeoning interest in marine palaeo-ice streams, and the timing and rate of deglaciation (e.g. Wellner et al. 2001;Canals et al., 2000; Lowe & 73 Anderson, 2002;Ó Cofaigh et al. 2002;Graham et al. 2009 115The first glacimarine investigations in Antarctica utilised echosounder data, till petrographic 116 studies and seismic data to reconstruct the expansion of grounded ice across the continental 117 shelf during the last glaciation (e.g. Kellogg et al. 1979; Anderson et al. 1980; Orheim & 118 Elverhøi, 1981;Domack, 1982;Haase, 1986;Kennedy & Anderson, 1989 Pudsey et al. 1994;Larter & Vanneste, 1995;O'Brien et al. 1999;Shipp et al. 1999; Canals 123 et al. 2000 Canals 123 et al. , 2002 Canals 123 et al. , 2003Anderson & Shipp, 2001;Wellner et al. 2001;Ó Cofaigh et al. 2002 Ó Cofaigh et al. , 124 2003 Ó Cofaigh et al. , 2005a Lowe & Anderson, 2003; Dowdeswell et al. 2004a,b;Evans et al. 2004Evans et al. , 2005 recently been demonstrated (Padman et al., 2010). 132In O'Brien et al. 1999O'Brien et al. , 2007 Table 2 provides a synthesis of the key physiographic data of each palaeo-ice stream in our 215 new inventory (see Fig. 1 and (ten Brink & Schneider, 1995). 228It is also apparent from 248The majority of the Antarctic palaeo-ice streams retreated across reverse slopes ( 2010) is suggested to relate to the much smaller size of its drainage basin (10,000-100,000 269 km 2 ), which is likely to have been much more sensitive to external and internal forcing. East Antarctic Peninsula, has also been associated with a change in basal processes (from 327 9 basal sliding to deformation) and an increase in ice velocity (Reinardy et al. 2011b The geometry of the basal reflector underlying the acoustically transparent unit ranges from 363 smooth and flat to irregular and undulating ( shelf (Pudsey et al. 1994Licht et al. 1996Licht et al. , 1998Licht et al. , 1999 between this bedrock and unconsolidated sediment further out on the shelf (Fig. 4c and Table 493 3) (Anderson et al. 2001; Camerlenghi et al. 2001;Wellner et al. 2001Wellner et al. , 2006...

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“…During the mid-to-late Pleistocene, ice advances were less extensive. During the last glacial cycle, the Amery Ice Shelf grounded only 100 km north of the present ice shelf edge and far from the continental shelf edge O'Brien et al, 1999) (Fig. PB-1).…”

Section: The Polar Ice Sheet (Late Miocene(?)-pleistocene)mentioning

confidence: 99%

Chapter 5 Cenozoic Climate History from Seismic Reflection and Drilling Studies on the Antarctic Continental Margin

Cooper

Brancolini

Escutia

et al. 2008

Antarctic Climate Evolution

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Ice shelf grounding zone features of western Prydz Bay, Antarctica: sedimentary processes from seismic and sidescan images

Cited by 61 publications

References 32 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

Antarctic palaeo-ice streams

Chapter 5 Cenozoic Climate History from Seismic Reflection and Drilling Studies on the Antarctic Continental Margin

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