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Asymmetric ice-sheet retreat pattern around northern Scotland revealed by marine geophysical surveys

Published online by Cambridge University Press:  05 August 2015

Tom Bradwell  and
Martyn Stoker
Tom Bradwell
Affiliation:
Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, UK British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK
Martyn Stoker
Affiliation:
British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK
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Abstract

This study uses marine geophysical data, principally single-beam and high-resolution multibeam echo sounder bathymetry, combined with seismic sub-bottom profiles, and existing Quaternary geological information, to map the glacial geomorphology of a large area of seafloor (∼50,000 km2) on the continental shelf around northern Scotland, from west of Lewis to north of the Orkney Islands. Our new mapping reveals the detailed pattern of submarine glacial landforms, predominantly moraines, relating to ice sheets that covered Scotland and much of the continental shelf during the Late Weichselian glaciation and earlier in the Mid to Late Pleistocene. The reconstructed retreat pattern based on geomorphological evidence highlights the large number of different retreat stages and the asymmetric, non-uniform evolution of this ice sheet sector during Late Weichselian deglaciation. Time-equivalent ice-front reconstructions show that marine sectors of the ice sheet, such as the Minch, changed their geometry significantly, perhaps rapidly; whilst other sectors remained relatively unchanged and stable. We suggest that this behaviour, governed principally by bed topography/bathymetry and ice dynamics, led to reorganisation of the Late Weichselian ice sheet as it retreated back to two main ice centres: one in Western Scotland and the other over Orkney and Shetland. This retreat pattern suggests relatively early deglaciation of NW Lewis (ca. 25 ka BP) and the mountains of far NW Scotland – the latter possibly forming a substantial ice-free land corridor. Our reconstructions differ from most previous syntheses, but are strongly supported by the independently-mapped offshore Quaternary succession and key onshore dating constraints.

Keywords

British–Irish Ice Sheetdeglaciationcontinental shelfLate Weichselianmultibeam bathymetry
Type
Articles
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 105 , Issue 4: Seabed Mapping for the 21st Century – the Marine Environmental Mapping Programme (MAREMAP) , December 2014 , pp. 297 - 322
Copyright
© 2015 BGS/NERC 

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References

7. References

Alley, R. B., Clark, P. U., Huybrechts, P. & Joughin, I. 2005. Ice-sheet and sea-level changes. Science 310, 456–60.Google Scholar
Andrews, I. J., Long, D., Richards, P. C., Thomson, A. R., Brown, S., Chesher, J. A. & McCormac, M. 1990. United Kingdom Offshore Regional Report: The Geology of the Moray Firth. London: HMSO for the British Geological Survey. 93 pp.Google Scholar
Baden-Powell, D. F.W. 1938. On the glacial and interglacial marine beds of North Lewis. Geological Magazine 75, 395–409.Google Scholar
Ballantyne, C. K., Schnabel, C. & Xu, S. 2009. Re-advance of the last British-Irish Ice Sheet during Greenland Interstade 1 (GI-1): the Wester Ross re-advance, NW Scotland. Quaternary Science Reviews 28, 783–89.Google Scholar
Ballantyne, C. K. & Stone, J. O. 2010. Did large ice caps persist on low ground in NW Scotland during the Lateglacial Interstade? Journal of Quaternary Science 27, 297–306.Google Scholar
Benn, D. I., Kirkbride, M. P., Owen, L. A. & Brazier, V. 2003. Glaciated valley landsystems. In Evans, D. J. A. (ed.) Glacial Landsystems, 372–406. London: Arnold.Google Scholar
Bennett, M. R. & Boulton, G. S. 1993. Deglaciation of the Younger Dryas or Loch Lomond Stadial ice-field in the northern Highlands, Scotland. Journal of Quaternary Science 8, 133–46.Google Scholar
Bradwell, T. 2013. Identifying palaeo-ice-stream tributaries on hard beds: mapping glacial bedforms and erosion zones in NW Scotland. Geomorphology 201, 397–414.Google Scholar
Bradwell, T., Stoker, M. & Larter, R. 2007. Geomorphological signature and flow dynamics of the Minch palaeo-ice stream, NW Scotland. Journal of Quaternary Science 22, 609–17.Google Scholar
Bradwell, T., Stoker, M. S., Golledge, N. R., Wilson, C. K., Merritt, J. W., Long, D., Everest, J. D., Hestvik, O. B., Stevenson, A. G., Hubbard, A. L., Finlayson, A. G. & Mathers, H. E. 2008a. The northern sector of the last British Ice Sheet: Maximum extent and demise. Earth-Science Reviews 88, 207–26.Google Scholar
Bradwell, T., Fabel, D., Stoker, M. S., Mathers, H., Mchargue, L. & Howe, J. A. 2008b. Ice caps existed throughout the Late-glacial Interstadial in northern Scotland. Journal of Quaternary Science 23, 401–07.Google Scholar
British Geological Survey (BGS). 1984. Orkney. Sea bed sediments and Quaternary geology. 1:250,000 map series. Keyworth, Nottingham: British Geological Survey.Google Scholar
British Geological Survey (BGS). 1989. Sutherland. Sea bed sediments and Quaternary geology. 1:250,000 map series. Keyworth, Nottingham: British Geological Survey.Google Scholar
British Geological Survey (BGS). 1994. Rona. Sea bed sediments and Quaternary geology. 1:250,000 map series. Keyworth, Nottingham: British Geological Survey.Google Scholar
British Geological Survey (BGS). 2012. Bedrock and Superficial Geology of the United Kingdom. DIGMAP50k. Digital geological map and database. Keyworth, Nottingham:0 British Geological Survey.Google Scholar
British Geological Survey (BGS). 2013. Bedrock and Quaternary Geology of the United Kingdom Continental Shelf. DIGMAP50k. Digital geological map and database. Keyworth, Nottingham: British Geological Survey.Google Scholar
Carr, S. J., Holmes, R., van der Meer, J. J. M., & Rose, J. 2006. The Last Glacial Maximum in the North Sea Basin: micromorphological evidence of extensive glaciation. Journal of Quaternary Science 21, 131–53.Google Scholar
Chiverrell, R. C., Thrasher, I. M., Thomas, G. S. P., Lang, A., Scourse, J. D., van Landeghem, K. J. J., Mccarroll, D., Clark, C. D., Ó Cofaigh, C., Evans, D. J. A. & Ballantyne, C. K. 2013. Bayesian modelling the retreat of the Irish Sea Ice Stream. Journal of Quaternary Science 28, 200–09.Google Scholar
Chiverrell, R. C. & Thomas, G. S. P. 2010. Extent and timing of the Last Glacial Maximum (LGM) in Britain and Ireland: a review. Journal of Quaternary Science 25, 535–49.Google Scholar
Clark, C. D., Evans, D. J. A., Khatwa, A., Bradwell, T., Jordan, C. J., Marsh, S. H., Mitchell, W. A. & Bateman, M. D. 2004. BRITICE: map and GIS database of landforms and features related to the last British Ice Sheet. Boreas 33, 359–75.Google Scholar
Clark, C. D., Hughes, A. L. C., Greenwood, S. L., Jordan, C. & Sejrup, H. P. 2012. Pattern and timing of retreat of the last British–Irish Ice Sheet. Quaternary Science Reviews 44, 112–46.Google Scholar
Clark, C. D., Fabel, D., Ó Cofaigh, C., Chiverrell, R., Scourse, J., Hindmarsh, R. C. A., Bradwell, T. & 25 others. 2014. BRITICE-CHRONO: constraining rates and style of marine-influenced ice sheet decay. Quaternary Revolutions: Quaternary Research Association, Annual Discussion Meeting, London. Abstract Volume, p. 16.Google Scholar
Davison, S. 2005. Reconstructing the Last Pleistocene (Late Devensian) Glaciation on the Continental Margin of Northwest Britain. Unpublished PhD Thesis. University of Edinburgh.Google Scholar
Dawson, A. G. 1984. Quaternary sea-level changes in western Scotland. Quaternary Science Reviews 3, 345–68.Google Scholar
Dowdeswell, J. A., Ottesen, D., Evans, J., Ó Cofaigh, C. & Anderson, J. B. 2008. Submarine glacial landforms and rates of ice-stream collapse. Geology 36, 819–22.Google Scholar
Dunlop, P., Shannon, R., McCabe, M., Quinn, R. & Doyle, E. 2010. Marine geophysical evidence for ice sheet extension and recession on the Malin Shelf: New evidence for the western limits of the British–Irish Ice Sheet. Marine Geology 276, 86–99.Google Scholar
Evans, D. J. A., Clark, C. D. & Mitchell, W. A. 2005. The last British Ice Sheet: a review of the evidence utilised in the compilation of the Glacial Map of Britain. Earth-Science Reviews 70, 253–312.Google Scholar
Evans, D. J. A. & Rea, B. R. 2003. Surging glacier landsystem. In Evans, D. J. A. (ed.) Glacial Landsystems, 259–89. London: Arnold.Google Scholar
Everest, J. D., Bradwell, T., Stoker, M. S. & Dewey, S. 2013. New age constraints for the maximum extent of the last British–Irish Ice Sheet (NW Sector). Journal of Quaternary Science 28, 2–7.Google Scholar
Finlayson, A. G., Golledge, N. R., Bradwell, T. & Fabel, D. 2011. Evolution of a Late-glacial mountain ice cap in Northern Scotland. Boreas 40, 536–54.Google Scholar
Finlayson, A., Fabel, D., Bradwell, T. & Sugden, D. E. 2014. Growth and decay of a marine-terminating sector of the last British–Irish Ice Sheet: a geomorphological reconstruction. Quaternary Science Reviews 83, 28–45.Google Scholar
Fyfe, J. A., Long, D. & Evans, D. 1993. United Kingdom offshore regional report: the geology of the Malin–Hebrides Sea area. London: HMSO for the British Geological Survey. 92 pp.Google Scholar
Gibbard, P. L. & Clark, C.D. 2011. Pleistocene Glaciation Limits in Great Britain. Developments in Quaternary Science 15, 75–93.Google Scholar
Golledge, N. R., Finlayson, A., Bradwell, T. & Everest, J. D. 2008. The last glaciation of Shetland, North Atlantic. Geografiska Annaler 90A, 37–53.Google Scholar
Gordon, J. E. & Sutherland, D. G. 1993. Quaternary of Scotland. London: Chapman and Hall. 695 pp.Google Scholar
Greenwood, S. L. & Clark, C. D. 2009. Reconstructing the last Irish Ice Sheet. 2: a geomorphologically driven model of ice sheet growth, retreat and dynamics. Quaternary Science Reviews 28, 3101–23.Google Scholar
Hall, A. M. 2013. The last glaciation of Shetland: local ice cap or invasive ice sheet? Norwegian Journal of Geology 93, 229–42.Google Scholar
Hall, A. M., Peacock, J. D. & Connell, E. R. 2003. New data for the Last Glacial Maximum in Great Britain and Ireland: a Scottish perspective on the paper by Bowen et al. (2002). Quaternary Science Reviews 22, 1551–54.Google Scholar
Howe, J. A., Dove, D., Bradwell, T. & Gaferia, J. 2012. Submarine gemorphology and glacial history of the Sea of the Hebrides. Marine Geology 315–318, 64–76.Google Scholar
Hubbard, A., Bradwell, T., Golledge, N. R., Hall, A. M., Patton, H., Sugden, D. E., Cooper, R. & Stoker, M. S. 2009. Dynamic cycles, ice streams and their impact on the extent, chronology and deglaciation of the British-Irish Ice Sheet. Quaternary Science Reviews 28, 758–76.Google Scholar
Hughes, A. L. C., Clark, C. D. & Jordan, C. J. 2010. Subglacial bedform map of Britain. Journal of Maps 2010, 543–63.Google Scholar
Hughes, A. L. C., Greenwood, S. L. & Clark, C.D. 2011. Dating constraints on the Last British–Irish ice sheet: a map and database. Journal of Maps 2011, 156–83.Google Scholar
IPCC. 2013. Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. (eds: Stocker, T. F. et al.) Cambridge: Cambridge University Press.Google Scholar
Kenyon, N. H. & Stride, A. H. 1970. The tide-swept continental shelf sediments between the Shetland Isles and France. Sedimentology 14, 159–73.Google Scholar
Lambeck, K. 1991. Glacial rebound and sea-level change in the British Isles. Terra Nova 3, 379–89.Google Scholar
Lambeck, K. 1993. Glacial Rebound of the British Isles—II. A high-resolution, high-precision model. Geophysical Journal International 115, 960–90.Google Scholar
Lindén, M. & Möller, P. 2005. Marginal formation of de Geer moraines and their implications to the dynamics of grounding-line recession. Journal of Quaternary Science 20, 113–33.Google Scholar
Milne, G. A., Shennan, I., Youngs, B. A. R., Waugh, A. I., Teferle, F. N., Bingley, R. M., Bassett, S. E., Cuthbert-Brown, C. & Bradley, S. L. 2006. Modelling the glacial isostatic adjustment of the UK region. Philosophical Transactions of the Royal Society, London 364, 931–48.Google Scholar
Ó Cofaigh, C. 2012. Ice sheets viewed from the ocean: the contribution of marine science to understanding modern and past ice sheets. Philosophical Transactions of the Royal Society A 370, 5512–39.Google Scholar
Ó Cofaigh, C., Dunlop, P. & Benetti, S. 2012. Marine geophysical evidence for Late Pleistocene ice sheet extent and recession off northwest Ireland, Quaternary Science Reviews 44, 147–59.Google Scholar
Ottesen, D. & Dowdeswell, J. A. 2006. Assemblages of submarine landforms produced by tidewater glaciers in Svalbard. Journal of Geophysical Research 111, F01016.Google Scholar
Peck, V. L., Hall, I. R., Zahn, R., Grousset, F. & Hemming, S. R. 2007. The relationship of Heinrich events and their European precursors over the past 60 ka BP: a multi-proxy ice-rafted debris provenance study in the North East Atlantic. Quaternary Science Reviews 26, 862–75.Google Scholar
Peltier, W. R. & Fairbanks, R. G. 2006. Global glacial ice volume and Last Glacial Maximum duration from an extended Barbados sea level record. Quaternary Science Reviews 25, 3322–37.Google Scholar
Phillips, W. M., Hall, A. M., Ballantyne, C. K., Binnie, S., Kubik, P. W. & Freeman, S. 2008. Extent of the last ice sheet in northern Scotland tested with cosmogenic 10Be exposure ages. Journal of Quaternary Science 23, 101–07.Google Scholar
Pritchard, H. D., Arthern, R. J., Vaughan, D. G. & Edwards, L. A. 2009. Extensive dynamic thinning on the margins of the Greenland and Antarctic ice sheets. Nature 461, 971–75.Google Scholar
Ritchie, J. D., Ziska, H., Johnson, H. & Evans, D. (eds). 2011. Geology of the Faroe–Shetland Basin and adjacent areas. British Geological Survey Research Report RR/11/01; Jarðfeingi Research Report RR/11/01.Google Scholar
Rydningen, T. A., Vorren, T. O., Laberg, J. S. & Kolstad, V. 2013. The marine-based NW Fennoscandian ice sheet: glacial and deglacial dynamics as reconstructed from submarine landforms. Quaternary Science Reviews 86, 126–41.Google Scholar
Schoof, C. 2012. Marine ice sheet instability. Journal of Fluid Mechanics 698, 62–72.Google Scholar
Scourse, J. D., Haapaniemi, A. I., Colmenero-Hidalgo, E., Peck, V. L., Hall, I. R., Austin, W. E. N., Knutz, P. C. & Zahn, R. 2009. Growth, dynamics and deglaciation of the last British–Irish ice sheet: the deep-sea ice-rafted detritus record. Quaternary Science Reviews 28, 3066–84.Google Scholar
Sejrup, H. P., Hjelstuen, B. O., Dahlgren, K. I. T., Haflidason, H., Kuijpers, A., Nygard, A., Praeg, D., Stoker, M. S. & Vorren, T. O. 2005. Pleistocene glacial history of the NW European continental margin. Marine and Petroleum Geology 22, 1111–29.Google Scholar
Sejrup, H. P., Nygard, A., Hall, A. M. & Haflidason, H. 2009. Middle and Late Weichselian (Devensian) glaciation history of south-western Norway, North Sea and eastern UK. Quaternary Science Reviews 28, 370–80.Google Scholar
Shaw, J., Piper, D. J. W., Fader, G. B. J., King, E. L., Todd, B. J., Bell, T., Batterson, M. J. & Liverman, D. G. E. 2006. A conceptual model of the deglaciation of Atlantic Canada. Quaternary Science Reviews 25, 2059–81.Google Scholar
Shennan, I., Bradley, S., Milne, G., Brooks, A., Bassett, S. & Hamilton, S. 2006. Relative sea-level changes, glacial isostatic modelling and ice-sheet reconstructions from the British Isles since the Last Glacial Maximum. Journal of Quaternary Science 21, 585–99.Google Scholar
Sissons, J. B. 1987. Shorelines and Isostasy in Scotland. In Smith, D. E. & Dawson, A. G. (eds) Shorelines and Isostasy. Institute of British Geographers Special Publication 16, 209–25. London: Academic Press. x + 387 pp.Google Scholar
Stoker, M. S. 1990. Glacially influenced sedimentation on the Hebridean slope, northwestern United Kingdom continental margin. In Dowdeswell, J. A. & Scourse, J. D. (eds) Glacimarine Environments: Processes and Sediments. Geological Society, London, Special Publication 53, 349–62. Bath: Geological Society Publishing House. 423 pp.Google Scholar
Stoker, M. S. 1995. The influence of glacigenic sedimentation on slope-apron development on the continental margin off Northwest Britain. In Scrutton, R. A., Stoker, M. S., Shimmield, G. B. & Tudhope, A. W. (eds) The Tectonics, Sedimentation and Palaeoceanography of the North Atlantic Region. Geological Society, London, Special Publication 90, 159–77. Bath: Geological Society Publishing House. 312 pp.Google Scholar
Stoker, M. S. 2013. Cenozoic sedimentary rocks. In Hitchen, K, Johnson, H. & Gatliff, R. W. (eds) Geology of the Rockall Basin and adjacent areas. British Geological Survey Research Report RR/12/03, 96–136. Keyworth, Nottingham: British Geological Survey.Google Scholar
Stoker, M. S., Hitchen, K. & Graham, C. G. 1993. United Kingdom offshore regional report: the geology of the Hebrides and West Shetland shelves, and adjacent deep-water areas. London: HMSO for the British Geological Survey. 150 pp.Google Scholar
Stoker, M. S., Leslie, A. B., Scott, W. D., Briden, J. C., Hine, N. M., Harland, R., Wilkinson, I. P., Evans, D. & Ardus, D. A. 1994. A record of late Cenozoic stratigraphy, sedimentation and climate change from the Hebrides Slope, NE Atlantic Ocean. Journal of the Geological Society, London 151, 235–49.Google Scholar
Stoker, M. S., Bradwell, T., Wilson, C., Harper, C., Smith, D. & Brett, C. 2006. Pristine fjord landsystem revealed on the seabed in the Summer Isles region, NW Scotland. Scottish Journal of Geology 42, 89–99.Google Scholar
Stoker, M. S., Bradwell, T., Howe, J. A., Wilkinson, I. M. & Mcintyre, K. 2009. Lateglacial ice cap dynamics in NW Scotland: evidence from the fjords. Quaternary Science Reviews 28, 3161–84.Google Scholar
Stoker, M. S., Balson, P. S., Long, D. & Tappin, D. R. 2011a. An overview of the lithostratigraphical framework for the Quaternary deposits on the United Kingdom continental shelf. British Geological Survey Research Report RR/11/03. Keyworth, Nottingham: British Geological Survey.Google Scholar
Stoker, M. S., McMillan, A. A. & Waters, C. N. 2011b. Quaternary Stratigraphical Chart: Northern Britain. British Geological Survey.Google Scholar
Stoker, M. S. & Bradwell, T. 2005. The Minch palaeo-ice stream, NW sector of the British–Irish ice sheet. Journal of the Geological Society, London 162, 425–28.Google Scholar
Stoker, M. S. & Bradwell, T. 2011. The Quaternary Geology of the Summer Isles Region. Sheet Explanation. Keyworth, Nottingham: British Geological Survey. 36 pp.Google Scholar
Stoker, M. S. & Holmes, R. 1991. Submarine end-moraines as indicators of Pleistocene ice-limits off north-west Britain. Journal of the Geological Society, London 148, 431–34.Google Scholar
Stoker, M. S. & Varming, T. 2011. Cenozoic (sedimentary). In Ritchie, J. D., Ziska, H., Johnson, H. & Evans, D. (eds) Geology of the Faroe–Shetland Basin and adjacent areas. British Geological Survey Research Report RR/11/01. 151–208; Jarðfeingi Research Report RR/11/01, 151–208.Google Scholar
Sutherland, D. G. 1984. The Quaternary deposits and landforms of Scotland and the neighbouring shelves: a review. Quaternary Science Reviews 3, 157–254.Google Scholar
Sutherland, D. G. & Walker, M. J. C. 1984. A Late Devensian ice-free area and possible interglacial site on the Isle of Lewis, Scotland. Nature 309, 701–03.Google Scholar
Todd, B. J., Valentine, P. C., Longva, O. & Shaw, J. 2007. Glacial landforms on German Bank, Scotian Shelf: evidence for Late Wisconsinan ice-sheet dynamics and implications for the formation of de Geer moraines. Boreas 36, 148–69.Google Scholar