Submarine end moraines on the continental shelf off NE Greenland – Implications for Lateglacial dynamics

Winkelmann, Daniel; Jokat, Wilfried; Jensen, Laura; Schenke, Hans-Werner

doi:10.1016/j.quascirev.2010.02.002

Cited by 76 publications

(71 citation statements)

References 30 publications

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“…A generally steep stoss-side results from subglacial sediments that were extruded or squeezed-out at the ice front and subsequently pushed (N)NE-ward, whereas the gentler lee-side is interpreted to have formed by proglacial gravity flows running down the ice-distal slope ( Fig. 5B; following the interpretation of Winkelmann et al, 2010). As the dimensions and orientations of the newly mapped recessional moraines are identical to those reported previously, they are also interpreted to reflect minor re-advances or short stillstands of the grounding line during a general (S)SW-ward retreat across the inter-ice stream ridge north of Burke Island.…”

Section: Recessional Morainesmentioning

confidence: 86%

Palaeo-ice stream pathways and retreat style in the easternmost Amundsen Sea Embayment, West Antarctica, revealed by combined multibeam bathymetric and seismic data

et al. 2015

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Multibeam swath bathymetry data sets collected over the past two decades have been compiled to identify palaeo-ice stream pathways in the easternmost Amundsen Sea Embayment. We mapped~3000 glacial landforms to reconstruct ice flow in the~250-km-long cross-shelf Abbot Trough. This bathymetric feature was occupied by a large ice stream, which was fed by two tributaries (Cosgrove and Abbot) and reached the continental shelf edge during the last maximum ice sheet advance. Geomorphological mapping has enabled a clear differentiation between subglacial landforms indicating warm-(e.g., megascale glacial lineations) and cold-based (e.g., hill-hole pairs) ice conditions on the continental shelf during the last glaciation. Grounding-zone wedges and recessional moraines, mapped within the palaeo-ice stream troughs and on adjacent sea-floor highs (referred to as inter-ice stream ridges) indicate grounding line stillstands or re-advances of the West Antarctic Ice Sheet during the last deglaciation of the shelf. We observe that the locations of grounding-zone wedges coincide with trough constrictions as well as local topographic highs of harder substrate. This combination of trough 'bottlenecks' and local pinning points on an otherwise retrograde slope is likely to have modified the pace of grounding-line retreat, causing the grounding zone to pause and deposit grounding-zone wedges. The episodic retreat recorded within Abbot Trough corresponds to post-glacial episodic retreat interpreted for the neighbouring Pine Island-Thwaites palaeo-ice stream trough, thus suggesting a uniform pattern of retreat across the eastern Amundsen Sea Embayment. Locally, indications are strong that a change in basal thermal regime of the ice from warm-to cold-based conditions occurred prior to final retreat, as hill-hole pairs overprint megascale glacial lineations. Further, the correlation of grounding-zone wedges with geological boundaries emphasises the influence of subglacial geology on ice stream flow. Our new geomorphological map of the easternmost Amundsen Sea Embayment resolves the pathways of palaeo-ice streams that were probably all active during the last maximum extent of the ice sheet, and the extent of adjacent inter-ice stream ridges. It reveals information about the style of, and the basal thermal regime during, the subsequent grounding line retreat. Such information provides an important empirical framework by which the accuracy of ice sheet models can be gauged.

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Section: Recessional Morainesmentioning

confidence: 86%

Palaeo-ice stream pathways and retreat style in the easternmost Amundsen Sea Embayment, West Antarctica, revealed by combined multibeam bathymetric and seismic data

et al. 2015

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“…The ridges located further east on the middle shelf (Fig. 1a, e), based on their asymmetric morphology and their inner structure, are probably recessional push moraines formed during episodic still-stands that punctuated the retreat of a Westwind Trough palaeo-ice stream (Winkelmann et al 2010). These recessional moraines are formed at the ice-sheet terminus by bulldozing sediment during minor re-advances of a grounded ice front or by deposition during significant halts (Golledge et al 2008).…”

Section: Discussionmentioning

confidence: 99%

“…Acquisition system ATLAS PARASOUND, 18 kHz and 22 kHz transmission frequencies. Images in (e), (f) and (g) modified from Winkelmann et al (2010).…”

Section: Discussionmentioning

confidence: 99%

“…The acoustically-transparent sediment is either: (a) confined to the lineations; or (b) occurs as a semi-continuous layer in which lineations are formed in the surface and sediment extends beneath the intervening grooves. A 160 km² area of the central Westwind Trough (Fig 1a) was surveyed systematically by Winkelmann et al (2010). A number of ridges are visible in water depths between 270 to 350 m (Fig.…”

Section: Descriptionmentioning

confidence: 99%

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Glacial lineations and recessional moraines on the continental shelf of NE Greenland

Arndt

Evans

2016

Memoirs

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“…This is particularly the case for much of the southwest, northwest and north Greenland shelf. In northeast Greenland, a few marine geophysical studies have recently been carried out [39,123], but they lack ground-truthing by dated sediment cores. Given the current interest in the dynamics of Greenland's contemporary marine-terminating outlet glaciers and the future contribution of the Greenland ice sheet to sea-level rise, the absence of data on the longer-term record of ice-sheet history from much of the Greenland continental margin represents a major research gap for which marine geology and geophysics will be central.…”

Section: (B) Investigations Of Ice-sheet History and Glacial Processementioning

confidence: 99%

Ice sheets viewed from the ocean: the contribution of marine science to understanding modern and past ice sheets

Cofaigh

2012

Phil. Trans. R. Soc. A.

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Over the last two decades, marine science, aided by technological advances in sediment coring, geophysical imaging and remotely operated submersibles, has played a major role in the investigation of contemporary and former ice sheets. Notable advances have been achieved with respect to reconstructing the extent and flow dynamics of the large polar ice sheets and their mid-latitude counterparts during the Quaternary from marine geophysical and geological records of landforms and sediments on glacierinfluenced continental margins. Investigations of the deep-sea ice-rafted debris record have demonstrated that catastrophic collapse of large (10 5 -10 6 km 2 ) ice-sheet drainage basins occurred on millennial and shorter time scales and had a major influence on oceanography. In the last few years, increasing emphasis has been placed on understanding physical processes at the ice-ocean interface, particularly at the grounding line, and on determining how these processes affect ice-sheet stability. This remains a major challenge, however, owing to the logistical constraints imposed by working in ice-infested polar waters and ice-shelf cavities. Furthermore, despite advances in reconstructing the Quaternary history of mid-and high-latitude ice sheets, major unanswered questions remain regarding West Antarctic ice-sheet stability, and the longterm offshore history of the East Antarctic and Greenland ice sheets remains poorly constrained. While these are major research frontiers in glaciology, and ones in which marine science has a pivotal role to play, realizing such future advances will require an integrated collaborative approach between oceanographers, glaciologists, marine geologists and numerical modellers.

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Submarine end moraines on the continental shelf off NE Greenland – Implications for Lateglacial dynamics

Cited by 76 publications

References 30 publications

Palaeo-ice stream pathways and retreat style in the easternmost Amundsen Sea Embayment, West Antarctica, revealed by combined multibeam bathymetric and seismic data

Palaeo-ice stream pathways and retreat style in the easternmost Amundsen Sea Embayment, West Antarctica, revealed by combined multibeam bathymetric and seismic data

Glacial lineations and recessional moraines on the continental shelf of NE Greenland

Ice sheets viewed from the ocean: the contribution of marine science to understanding modern and past ice sheets

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