The morphological characteristics of ribbed moraine

Dunlop, P; Clark, Chris D.

doi:10.1016/j.quascirev.2006.01.002

Cited by 156 publications

(196 citation statements)

References 34 publications

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“…Similar to other ribbed moraine terrain, there are spatial associations with the glacial lineations mapped on the island (Dunlop and Clark, 2006). While drumlinisation of the main ridges has commonly been reported in other regions (Dunlop & Clark, 2006;Trommelen et al, 2014), it is observed less frequently in Newfoundland and, where it does occur, it tends to be poorly developed.…”

Section: Ribbed Morainessupporting

confidence: 61%

“…The distribution of mapped ribbed moraines extends the previously documented population of ribbed moraine in the Glacial Map of Canada (Prest et al, 1968) with 28% of mapped ridges recorded in areas not previously categorised as ribbed terrain. The mapped ribbed moraines commonly display similar morphological characteristics to those reported in the Dunlop and Clark (2006) classification and include, for example, classic downstream curving, broad arcuate, jagged and hummocky ridges ( Figure 5). Figure 1), (e) hummocky ribbed moraine (Box 5e in Figure 1) and (f) cross-cutting ribbed moraines (Box 5f in Figure 1).…”

Section: Ribbed Morainesmentioning

confidence: 62%

“…These regularly spaced ridges, aligned transverse to ice flow, are widely accepted to have formed subglacially and are located across considerable areas of the former Laurentide, Fennoscandian, British-Irish and Newfoundland ice sheets (NISs) (Aylsworth & Shilts, 1989;Bouchard, 1989;Clark, 1999;Clark & Meehan, 2001;Dunlop & Clark, 2006;Knight & McCabe, 1997;Lundqvist, 1969Lundqvist, , 1989Marich et al, 2005;Prest et al, 1968;Stokes, Lian, Tulaczyk, & Clark, 2008). Ridge lengths range from 100 m to 3873 m, with 63% of landforms having a typical length range of 300-1200 m (mean 447 m), which is consistent with typical lengths reported in a large representative database by Dunlop and Clark (2006). The distribution of mapped ribbed moraines extends the previously documented population of ribbed moraine in the Glacial Map of Canada (Prest et al, 1968) with 28% of mapped ridges recorded in areas not previously categorised as ribbed terrain.…”

Section: Ribbed Morainesmentioning

confidence: 99%

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The subglacial imprint of the last Newfoundland Ice Sheet, Canada.

McHenry

Dunlop

2015

Journal of Maps

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The former Newfoundland Ice Sheet was situated on the fringes of the northeast Atlantic Ocean during the Wisconsinan glaciation ( 80-10 ka BP). Its geographic position indicates that it was likely to have been influenced by a number of external and internal forcing mechanisms including configuration changes in the Laurentide Ice Sheet with which it converged during the last glacial maximum, ice streams, changes in oceanic circulation and fluctuating sea levels. This makes Newfoundland a key location for investigating the dynamic response of ice sheets to these types of internal and external drivers. An established methodology for investigating ice sheet dynamics is to use the landform record to reconstruct the dynamic behaviour and configuration of the ice sheet. This provides a relative chronology of former ice sheet events during glacial cycles. A fundamental requirement of this approach is a detailed glacial geomorphology map that records the spatial distribution of individual subglacial bedforms across the former ice sheet bed. This paper presents a new subglacial bedform map of the Island of Newfoundland. It was produced as part of a mapping programme which used 10 m resolution Satellite Pour l'Observation de la Terre satellite imagery, Shuttle Radar Topography Mission and Canadian Digital Elevation Data. The map records the spatial distribution of 126,000 individually mapped glacial lineations and ribbed moraines and extends the number and spatial extent of each landform across the island. It is a new data set which has the potential to provide important insights into former ice sheet behaviour in this region.

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Section: Ribbed Morainessupporting

confidence: 61%

Section: Ribbed Morainesmentioning

confidence: 62%

Section: Ribbed Morainesmentioning

confidence: 99%

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The subglacial imprint of the last Newfoundland Ice Sheet, Canada.

McHenry

Dunlop

2015

Journal of Maps

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“…An alternative 377 interpretation is that these transverse ridges could be ribbed moraines, thereby associated with ice 378 flow, and potentially inter-related with ice streaming and the surrounding drumlins (e.g. Dunlop and 379 Clark, 2006). 380…”

Section: Interpretation Of Landform Record -Moraines 368mentioning

confidence: 99%

Submarine glacial landforms record Late Pleistocene ice-sheet dynamics, Inner Hebrides, Scotland

Dove

Arosio

Finlayson

et al. 2015

Quaternary Science Reviews

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We use ∼7000km 2 of high-resolution swath bathymetry data to describe and map the submarine glacial geomorphology, and reconstruct Late Pleistocene ice sheet flow configurations and retreat dynamics within the Inner Hebrides, western Scotland. Frequently dominated by outcrops of structurally complex bedrock, the seabed also comprises numerous assemblages of well-preserved glacigenic landforms typical of grounded ice sheet flow and punctuated ice-margin retreat. The occurrence and character of the glacially streamlined landforms is controlled in part by the shallow geology and topography, however these factors alone cannot account for the location, orientation, and configuration of the observed landforms. We attribute the distribution of these elongate streamlined landforms to the onset zone of the former Hebrides Ice Stream (HIS) – part of a major ice stream system that drained 5–10% of the last British–Irish Ice Sheet (BIIS). We suggest this geomorphic signature represents the transition from slow ‘sheet flow’ to ‘streaming flow’ as ice accelerated out from an environment characterized by numerous bedrock obstacles (e.g. islands, headlands), towards the smooth, sediment dominated shelf. The majority of streamlined landforms associated with the HIS indicate ice sheet flow to the southwest, with regional-scale topography clearly playing a major role in governing the configuration of flow. During maximal glacial conditions (∼29–23ka) we infer that the HIS merged with the North Channel-Malin Shelf Ice Stream to form a composite ice stream system that ultimately reached the continental shelf edge at the Barra-Donegal Trough-Mouth Fan. Taken collectively however, the pattern of landforms now preserved at seabed (e.g. convergent flow indicators, cross-cutting flow sets) is more indicative of a thinning ice mass, undergoing reorganization during overall ice sheet retreat (during latter stages of Late Weischselian glaciation). Suites of moraines overprinting the streamlined landforms suggest partial stabilization of the HIS prior to the ice sheet retreating to more isolated, topographically confined troughs and basins. Retreat from the shelf towards, and back into the Inner Hebrides may have been rapid due the prevalence of overdeepened troughs. Within the near-shore fjord-like troughs and deeps, basin-aligned streamlined landforms indicate the subsequent flow of thinner topographically partitioned ice masses, and overprinted moraines record further ice margin retreat, potentially along tide-water margins. This work provides the first geomorphological constraints for this large marine-influenced sector of the former BIIS. We also shed new light on the glacial geomorphic record found at the transition from terrestrial to marine continental-shelf settings, and examine the interplay between substrate geology, bed topography/bathymetry, and grounding-line positions – relationships which are important for characterizing contemporary marine ice sheet margins

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“…Boulton & Clark, 1990;Boulton, Dongelmans, Punkari, & Broadgate, 2001;Clark, Knight, & Gray, 2000;Greenwood & Clark 2009;Greenwood & Kleman, 2010;Kleman & Borgström, 1996;Punkari, 1997;Sarala, 2006). However, recent work on these bedforms indicates that using morphology alone to establish ice flow direction may not be definitive, particularly if small study areas and sample sizes are used (Dunlop & Clark, 2006;Spagnolo, Clark, Hughes, Dunlop, & Stokes, 2010). Also, not all areas of glaciated terrain experienced a bedforming event or retain evidence of one, though glacial erosional forms such as striae may provide ice flow alignment data if present on exposed bedrock surfaces (Glasser & Bennett, 2004;Iverson, 1991;Smith & Knight, 2011).…”

Section: Introductionmentioning

confidence: 99%

Principal component analysis of the geochemistry of soil developed on till in Northern Ireland

et al. 2013

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This paper presents results from the first regional statistical analysis of soils developed on till in Northern Ireland, using the Geological Survey of Northern Ireland's Tellus geochemical database. Till geochemistry is largely determined by its parent bedrock and soils developed on tills are known to inherit this geochemical signature. Soil geochemistry from areas of till can therefore be used to establish sediment provenance which in turn provides information on palaeo ice flow directions and ice sheet history. In this study, we use Principal Component Analysis to establish geochemical groupings that can be related back to likely bedrock parent material for the tills in the region. The maps, presented here at 1:445,000 scale, show the results of the first regional investigation of soil geochemistry of part of the northern sector of the Irish Ice Sheet. The results indicate that the upper surface of the majority of tills in the study area have a close relationship to local bedrock with rapid geochemical changes observed at lithological boundaries. This suggests that tills in this sector of the Irish Ice Sheet are primarily local in origin, indicating rapid entrainment of bedrock and low rates of evacuation of debris to the ice margin.

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The morphological characteristics of ribbed moraine

Cited by 156 publications

References 34 publications

The subglacial imprint of the last Newfoundland Ice Sheet, Canada.

The subglacial imprint of the last Newfoundland Ice Sheet, Canada.

Submarine glacial landforms record Late Pleistocene ice-sheet dynamics, Inner Hebrides, Scotland

Principal component analysis of the geochemistry of soil developed on till in Northern Ireland

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