The extension of the Late Weichselian/Late Devensian ice sheets in the North Sea Basin

Ehlers, Jürgen; Wingfield, R.T.R.

doi:10.1002/jqs.3390060406

Cited by 72 publications

(72 citation statements)

References 27 publications

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“…For example, in Sutherland's (1984) reconstruction of an independent BIIS, ice terminates at the eastern margin of the Wee Bankie, off the eastern Scottish coast (Figure 1), and, following Synge (1956) and Flinn (1967), parts of Caithness, Buchan and northern Lewis fall beyond its limits. These nonglaciated enclaves subsequently appeared in many published reconstructions of the north-eastern sector of the last BIIS (Bowen et al, 1986;Bowen, 1989;Nesje and Sejrup, 1988;Boulton et al, 1991;Ehlers and Wingfield, 1991;Lambeck, 1995;Bowen et al, 2002;, despite the evidence for them having been seriously questioned (Peacock, 1997;Hall and Bent, 1990;Hall, 1997;Whittington et al, 1998;Whittington and Hall, 2002), or refuted . Nunataks formerly identified in the NW Highlands and Outer Hebrides by Ballantyne et al (1998) lent support for a thin, low-profile ice sheet, but reinterpretation of the trimline evidence now indicates that the ice exceeded 900 m and 600 m in altitude over these areas respectively and that Scotland was completely buried beneath ice during the last glaciation (Ballantyne, 2010).…”

Section: Glacial Reconstructionsmentioning

confidence: 99%

Middle to Late Devensian glaciation of north‐east Scotland: implications for the north‐eastern quadrant of the last British–Irish ice sheet

Merritt

Connell

Hall

2016

J Quaternary Science

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We present a review of over 175 years of research into the Middle to Late Devensian (Weichselian) glaciation of north-east Scotland based crucially on both its lithostratigraphic and geomorphic records. The location of the region, and surrounding seabed, makes this unusually detailed record significant for deciphering the former interactions and dynamics of Scottish and Scandinavian ice within the North Sea Basin (NSB), which continue to be controversial. A twelve-stage event stratigraphy is proposed based on a parsimonious interpretation of stratigraphic relationships, till lithology and regional clast fabrics, striae, subglacial bedforms, ice-marginal features and published geochronometry at critical sites. The record of regional glaciation supports converging evidence that the north-eastern quadrant of the last British and Irish Ice Sheet (BIIS) reached its maximum spatial extent in the late Middle-to early Late Devensian and later re-expanded following widespread internal glacial reorganisations, marine transgression and partial retreat from the central NSB. Retreat was interrupted by several glacial readvances of limited extent. Fieldcaptured data helps identify important events that are not clearly resolved from remote sensing alone, particularly regarding growth phases of the last glaciation.

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Section: Glacial Reconstructionsmentioning

confidence: 99%

Middle to Late Devensian glaciation of north‐east Scotland: implications for the north‐eastern quadrant of the last British–Irish ice sheet

Merritt

Connell

Hall

2016

J Quaternary Science

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“…Key indicators of glacial activity on the UK continental shelf include several generations of tunnel valleys in the North Sea (Cameron et al, 1987;Wingfield, 1989Wingfield, , 1990Ehlers and Wingfield, 1991;Huuse and Lykke-Andersen, 2000;Praeg, 2003;Lonergan et al, 2006), and moraines preserved to the NE and NW of Britain (e.g. Rokoengen et al, 1982;Stoker et al, 1985Stoker et al, , 1993Selby, 1989;Hall and Bent, 1990;Stoker and Holmes, 1991;Austin and Kroon, 1996).…”

Section: Offshore Evidencementioning

confidence: 99%

“…Radiocarbon dates between 21.7 ka and 17.7 ka 14 C BP, obtained from lignitised wood sampled from glacimarine deposits adjacent to the eastern margin of the Wee Bankie moraine (Holmes, 1977), have traditionally formed the basis for interpreting these moraines as the maximum eastern limit of the last BIS, at around 18-22 ka BP (Sutherland, 1984;Boulton et al, 1985Boulton et al, , 1991Boulton et al, , 2002Cameron et al, 1987;Hall and Bent, 1990;Lambeck, 1991;Bowen et al, 2002;. However, such a limit fails to reconcile the occurrence of subglacial tunnel valleys largely formed during the Late Devensian (MIS 2), located east of these moraines (Wingfield, 1989;Ehlers and Wingfield, 1991;Lonergan et al, 2006).…”

Section: Extent Of Glaciationmentioning

confidence: 99%

The northern sector of the last British Ice Sheet: Maximum extent and demise

Bradwell

Stoker

Golledge

et al. 2008

Earth-Science Reviews

284

402

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Strongly divided opinion has led to competing, apparently contradictory, views on the timing, extent, flow configuration and decay mechanism of the last British Ice Sheet. We review the existing literature and reconcile some of these differences using remarkable new seabed imagery. This bathymetric data provides unprecedented empirical evidence of confluence and subsequent separation of the last British and Fennoscandian Ice Sheets. Critically, it also allows a viable pattern of ice-sheet disintegration to be proposed for the first time. Covering the continental shelf around the northern United Kingdom, extensive echosounder data reveals striking geomorphic evidence -in the form of tunnel valleys and moraines -relating to the former British and Fennoscandian Ice Sheets. The pattern of tunnel valleys in the northern North Sea Basin and the presence of large moraines on the West Shetland Shelf, coupled with stratigraphic evidence from the Witch Ground Basin, all suggest that at its maximum extent a grounded ice sheet flowed from SE to NW across the northern North Sea Basin, terminating at the continental shelf edge. The zone of confluence between the British and much larger Fennoscandian Ice Sheets was probably across the northern Orkney Islands, with fast-flowing ice in the Fair Isle Channel focusing sediment delivery to the Rona and Foula Wedges. This period of maximum confluent glaciation (c. 30-25 ka BP) was followed by a remarkable period of large-scale ice-sheet re-organisation. We present evidence suggesting that as sealevel rose, a large marine embayment opened in the northern North Sea Basin, as far south as the Witch Ground Basin, forcing the two ice sheets to decouple rapidly along a north-south axis east of Shetland. As a result, both ice-sheets rapidly adjusted to new quasi-stable margin positions forming a second distinct set of moraines (c. 24-18 ka BP). The lobate overprinted morphology of these moraines on the mid-shelf west of Orkney and Shetland indicates that the re-organisation of the British Ice Sheet was extremely dynamic -probably dominated by a series of internally forced readvances. Critically, much of the ice in the low-lying North Sea Basin may have disintegrated catastrophically as decoupling progressed in response to rising sea levels. Final-stage deglaciation was marked by near-shore ice streaming and increasing topographic control on ice-flow direction. Punctuated retreat of the British Ice Sheet continued until c. 16 ka BP when, following the North Atlantic iceberg-discharge event (Heinrich-1), ice was situated at the present-day coastline in NW Scotland.

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“…Various models have been proposed based upon different combinations of morphological and stratigraphic evidence. The distribution of large incisions, interpreted as subglacial tunnel valleys, has been used by some researchers to demarcate the last ice limit (Valentin, 1957;Flinn, 1967;Jansen et al, 1979;Ehlers and Wingfield, 1991). However, both the age and the origin of the North Sea "tunnel valleys" pose considerable problems for ice sheet reconstructions.…”

Section: North Sea Offshore Evidencementioning

confidence: 99%

The last British Ice Sheet: A review of the evidence utilised in the compilation of the Glacial Map of Britain

Evans

Clark

Mitchell

2005

Earth-Science Reviews

128

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This paper reviews the evidence presently available (as at December 2003) in an effort to stimulate further research on the last British Ice Sheet and promote a reconstruction of ice sheet behaviour based on glacial geology and geomorphology. The wide range of evidence that has been scrutinized for inclusion on the glacial map is assessed with respect to the variability of its quality and quantity and the existing controversies in ice sheet reconstructions. Landforms interpreted as being of unequivocal ice-marginal origin (moraines, ice-contact glacifluvial landforms and lateral meltwater channels) and till sheet margins are used in conjunction with available chronological control to locate former glacier and ice-sheet margins throughout the last glacial cycle. Subglacial landforms (drumlins, flutings and eskers) have been used to demarcate former flow patterns within the ice sheet. The compilation of evidence in a regional map is crucial to any future reconstructions of palaeo-ice sheet dynamics and will provide a clearer understanding of ice sheet configuration, ice divide migration and ice thickness and coverage for the British Ice Sheet as it evolved through the last glacial cycle.2

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The extension of the Late Weichselian/Late Devensian ice sheets in the North Sea Basin

Cited by 72 publications

References 27 publications

Middle to Late Devensian glaciation of north‐east Scotland: implications for the north‐eastern quadrant of the last British–Irish ice sheet

Middle to Late Devensian glaciation of north‐east Scotland: implications for the north‐eastern quadrant of the last British–Irish ice sheet

The northern sector of the last British Ice Sheet: Maximum extent and demise

The last British Ice Sheet: A review of the evidence utilised in the compilation of the Glacial Map of Britain

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