Hostname: page-component-cd9895bd7-dk4vv Total loading time: 0 Render date: 2024-12-27T14:03:45.336Z Has data issue: false hasContentIssue false
  • English
  • Français

Rapid thinning of the Welsh Ice Cap at 20–19 ka Based on 10Be Ages

Published online by Cambridge University Press:  20 January 2017

Philip D. Hughes ,
Neil F. Glasser  and
David Fink
Philip D. Hughes*
Affiliation:
Geography, School of Environment, Education and Development, University of Manchester, Manchester M13 9PL, England, UK
Neil F. Glasser
Affiliation:
Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth SY23 3DB, Wales, UK
David Fink
Affiliation:
Australian Nuclear Science and Technology Organisation, PMB1, Menai, NSW 2234, Australia
*
⁎Corresponding author. E-mail address:Philip.hughes@manchester.ac.uk (P.D. Hughes).
Get access Rights & Permissions [Opens in a new window]

Abstract

New 10Be ages from the summits of three mountain areas of North Wales reveal a very similar exposure timing as the Welsh Ice Cap thinned after the global Last Glacial Maximum. Eight bedrock and one boulder sample gave a combined arithmetic mean exposure age of 19.08 ± 0.80 ka (4.2%, 1σ). Similar exposure ages over a 320 m vertical range (824 to 581 m altitude) show that ice cap thinning was very rapid and spatially uniform. Using the same production rate and scaling scheme, we recalculated six published 10Be exposure ages from the nearby Arans, which also covered a similar elevation range from 608 to 901 m and obtained an arithmetic mean of 19.41 ± 1.45 ka (7.5%, 1σ). The average exposure age of all 15 accepted deglaciation ages is 19.21 ± 1.07 (5.6%, 1σ). The complete dataset from North Wales provides very strong evidence indicating that these summits became exposed as nunataks at 20–19 ka. This result provides important insight to the magnitude of ice surface lowering and behavior of the Welsh Ice Cap during the last deglaciation that can be compared to other ice masses that made up the British-Irish Ice Sheet.

Keywords

Welsh Ice CapNunatak10BeCosmogenic exposure datingRhinogsMoelwynsArenigsDeglaciation
Type
Original Articles
Information
Quaternary Research , Volume 85 , Issue 1 , January 2016 , pp. 107 - 117
Copyright
University of Washington

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Addison, K., (1997). Classic landforms of Snowdonia. Classic Landforms Guides. Geographical Association, (60 pp.).Google Scholar
Alley, R.B., Brook, E.J., Anandakrishnan, S., (2002). A northern lead in orbital band: north"south phasing of Ice-Age events.. Quaternary Science Reviews 21, 431–441.CrossRefGoogle Scholar
Balco, G., (2011). Contributions and unrealized potential contributions of cosmogenic-nuclide exposure dating to glacier chronology, 1990"2010.. Quaternary Science Reviews 30, 3–27.CrossRefGoogle Scholar
Balco, G., Sch"fer, J.M., (2006). Cosmogenic-nuclide and varve chronologies for the deglaciation of southern New England.. Quaternary Geochronology 1, 15–28.Google Scholar
Balco, G., Stone, J., Lifton, N., Dunai, T., (2008). A complete and easily accessible means of calculating surface exposure ages or erosion rates from 10Be and 26Al measurements.. Quaternary Geochronology 3, 174–195.Google Scholar
Ball, D.F., Goodier, R., (1970). Morphology and distribution of features resulting from frost-action in Snowdonia.. Field Studies 3, 193–218.Google Scholar
Ballantyne, C.K., (2010). Extent and deglacial chronology of the last British-Irish Ice Sheet: implications of exposure dating using cosmogenic isotopes.. Journal of Quaternary Science 25, 515–534.Google Scholar
Ballantyne, C.K., Stone, J.O., (2012). Did large ice caps persist on low ground in north-west Scotland during the LateglacialInterstade?. Journal of Quaternary Science 27, 297–306.Google Scholar
Ballantyne, C.K., Stone, J.O., (2015). Trimlines, blockfields and the vertical extent of the last ice sheet in southern Ireland.. Boreas 44, 277–287.Google Scholar
Bendle, J.M., Glasser, N.F., (2012). Palaeoclimatic reconstruction from Lateglacial (Younger DryasChronozone) cirque glaciers in Snowdonia, North Wales.. Proceedings of the Geologists' Association 123, 130–145.Google Scholar
Braucher, R., Bourles, D., Merchel, S., Vidal Romani, J., Fernadez-Mosquera, D., Marti, K., L"anni, L., Chauvet, F., Arnold, M., Auma"tre, G., Keddadouche, K., (2013). Determination of muon attenuation lengths in depth profiles from in situ produced cosmogenic nuclides.. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 294, 484–490.CrossRefGoogle Scholar
Brown, M.J.F., Ellis-Gruffydd, I.D., Foster, H.D., Unwin, D.J., (1967). A new radiocarbon date for Wales.. Nature 213, 1220–1221.Google Scholar
Child, D., Elliott, G., Misfud, C., Smith, A.M., Fink, D., (2000). Sample processing for Earth science studies at ANTARES.. Nuclear Instruments and Methods B172, 856–860.CrossRefGoogle 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., Cofaigh, "., Evans, D.J.A., Ballantyne, C.K., (2013). Bayesian modelling of the retreat of the Irish Sea Ice Stream.. Journal of Quaternary Science 28, 200–209.CrossRefGoogle Scholar
Chmeleff, J., von Blanckenburg, F., Kossert, K., Jakob, D., (2010). Determination of the 10Be half-life by multicollectorICP-MS and liquid scintillation counting.. Nuclear Instruments and Methods in Physics Research B 268, 192–199.CrossRefGoogle 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, 112–146.Google Scholar
Darwin, C., (1848). On the transportal of erratic boulders from a lower to a higher level.. Quarterly Journal of the Geological Society 4, 315–323.Google Scholar
Denton, G.H., Anderson, R.F., Toggweiler, J.R., Edwards, R.L., Schaefer, J.M., Putnam, A.E., (2010). The last glacial termination.. Science 328, 1652–1656.Google Scholar
Dielforder, A., Hetzel, R., (2014). The deglaciation history of the Simplon region (southern Swiss Alps) constrained by 10Be exposure dating of ice-molded bedrock surfaces.. Quaternary Science Reviews 84, 26–38.Google Scholar
Dunai, T.J., (2002). Influence of secular variation of the geomagnetic field on production rates of in situ produced cosmogenic nuclides.. Earth and Planetary Science Letters 193, 197–212.CrossRefGoogle 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
Fearnsides, W.G., (1905). On the geology of ArenigFawr and MoelLlyfnant.. Quarterly Journal of the Geological Society 61, 608–640.CrossRefGoogle Scholar
Fink, D., Smith, A., (2007). An inter-comparison of 10Be and 26Al AMS reference standards and the 10Be half-life.. Nuclear Instruments and Methods B259, 600–609.Google Scholar
Fink, D., McKelvey, B., Hannan, D., Newsome, D., (2000). Cold rocks, hot sands: in-situ cosmogenic applications in Australia at ANTARES.. Nuclear Instruments and Methods in Physics Research B172, 838–846.CrossRefGoogle Scholar
Foster, H.D., (1968). The glaciation of the Harlech Dome. University College London (University of London), .Google Scholar
Foster, H.D., (1970a). Sarn Badrig, a submarine moraine in Cardigan Bay, north Wales.. Zeitschriftf"r Geomorphologie 14, 473–486.Google Scholar
Foster, H.D., (1970b). Establishing the age and geomorphological significance of sorted stone-stripes in the Rhinog Mountains, North Wales.. Geografiska Annaler 52, 96–102.Google Scholar
EDINA Geology Digimap, (2014). British Geological Survey (BGS) Data. http://edina.ac.uk/digimap/index.shtml.Google Scholar
Glasser, N.F., Hughes, P.D., Fenton, C., Schnabel, C., Rother, H., (2012). 10Be and 26Al exposure-age dating of bedrock surfaces on the Aran ridge, Wales: evidence for a thick Welsh Ice Cap at the Last Glacial Maximum.. Journal of Quaternary Science 27, 97–104.Google Scholar
Greenly, E., (1919). The geology of Anglesey. Memoirs of the Geological Survey of Great Britain. HMSO, London.Google Scholar
Gutjahr, M., Lippold, J., (2011). Early arrival of Southern Source Water in the deep North Atlantic prior to Heinrich event 2.. Paleoceanography 26, PA2101 10.1029/2011PA002114.Google Scholar
Hughes, P.D., (2002a). Loch Lomond Stadial glaciers in the Aran and Arenig Mountains, North Wales, Great Britain.. Geological Journal 37, 9–15.Google Scholar
Hughes, P.D., (2002b). Nunataks and the surface altitude of the last ice-sheet in southern Snowdonia, Wales.. Quaternary Newsletter 97, 19–25.Google Scholar
Hughes, P.D., (2002c). Nunataks and the surface altitude of the last ice-sheet in southern Snowdonia, Wales: a reply to McCarroll and Ballantyne (2002).. Quaternary Newsletter 98, 15–17.Google Scholar
Hughes, P.D., (2009). Loch Lomond Stadial (Younger Dryas) glaciers and climate in Wales.. Geological Journal 44, 375–391.Google Scholar
Hughes, P.D., Gibbard, P.L., (2015). A stratigraphical basis for the Last Glacial Maximum (LGM).. Quaternary International 383, 174–185.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, 156–183.10.4113/jom.2011.1145.CrossRefGoogle Scholar
Jansson, K.N., Glasser, N.F., (2005). Palaeoglaciology of the Welsh sector of the British"Irish Ice Sheet.. Journal of the Geological Society, London 162, 25–37.Google Scholar
Kohl, C.P., Nishiizumi, K., (1992). Chemical isolation of quartz for measurement of in situ-produced cosmogenic nuclides.. Geochimica et Cosmochimica Acta 56, 3583–3587.CrossRefGoogle Scholar
Korschinek, G., Bergmaier, A., Faestermann, T., Gerstmann, U.C., Knie, K., Rugel, G., Wallner, A., Dillmann, A., Dollinger, G., Liese von Gostomski, Ch., Kossert, K., Maiti, M., Poutivtsev, M., Remmert, A., (2010). A new value for the half-life of 10Be by heavy-ion elastic recoil detection and liquid scintillation counting.. Nuclear Instruments and Methods in Physics Research B 268, 187–191.Google Scholar
McCarroll, D., Ballantyne, C.K., (2000). The last ice sheet in Snowdonia.. Journal of Quaternary Science 15, 765–778.Google Scholar
McCarroll, D., Ballantyne, C.K., (2002). Nunataks and the surface altitude of the last ice-sheet in southern Snowdonia, Wales: a comment on Hughes (2002).. Quaternary Newsletter 98, 10–14.Google Scholar
McCormack, D.C., Brocklehurst, S.H., Irving, D.H.B., Fabel, D., (2011). Cosmogenic 10Be insights into the extent and chronology of the last deglaciation in Wester Ross, northwest Scotland.. Journal of Quaternary Science 26, 97–108.Google Scholar
Mifsud, C., Fujioka, T., Fink, D., (2013). Extraction and purification of quartz in rock using hot-phosphoric acid for in situ cosmogenic exposure dating.. Nuclear Instruments and Methods B294, 203–207.Google Scholar
Patton, H., Hubbard, A., Glasser, N.F., Bradwell, T., Golledge, N.R., (2013a). The last Welsh Ice Cap: part I " modelling its evolution, sensitivity and associated climate.. Boreas 42, 471–490.Google Scholar
Patton, H., Hubbard, A., Glasser, N.F., Bradwell, T., Golledge, N.R., (2013b). The last Welsh Ice Cap: part 2 " dynamics of a topographically controlled ice cap.. Boreas 42, 491–510.Google Scholar
Patton, H., Hubbard, A., Bradwell, T., Glasser, N.F., Hambrey, M.J., Clark, C.D., (2013c). Rapid deglaciation: asynchronous retreat dynamics between the Irish Sea Ice Stream and terrestrial outlet glaciers.. Earth Surface Dynamics 1, 53–65.Google Scholar
Reimer, P.J., Bard, E., Bayliss, A., Beck, J.W., Blackwell, P.G., Bronk Ramsey, C., Buck, C.E., Cheng, H., Edwards, R.L., Friedrich, M., Grootes, P.M., Guilderson, T.P., Haflidason, H., Hajdas, I., Hatt", C., Heaton, T.J., Hogg, A.G., Hughen, K.A., Kaiser, K.F., Kromer, B., Manning, S.W., Niu, M., Reimer, R.W., Richards, D.A., Scott, E.M., Southon, J.R., Turney, C.S.M., van der Plicht, J., (2013). IntCal13 and MARINE13 radiocarbon age calibration curves 0"50000 years cal BP.. Radiocarbon 55, 410.2458/azu_js_rc.55.16947.Google Scholar
Rolfe, C.J., Hughes, P.D., Fenton, C.R., Schnabel, C., Xu, S., Brown, A.G., (2012). Paired 10Be and 26Al exposure ages from Lundy: new evidence for the extent and timing of Devensian glaciation in the southern British Isles.. Quaternary Science Reviews 43, 61–73.Google Scholar
Rowlands, B.M., (1971). Radiocarbon evidence of the age of an Irish Sea Glaciation in the Vale of Clwyd.. Nature 230, 9–11.Google Scholar
Rowlands, B.M., (1979). The Arenig region: a study in the Welsh Pleistocene.. Cambria 6, 13–31.Google Scholar
Smith, B., George, T.N., (1961). North Wales. 3rd EditionBritish Regional Geology, HMSO, London.(96pp.).Google Scholar
Stone, J.O., (2000). Air pressure and cosmogenic isotope production.. Journal of Geophysical Research-Solid Earth 105, 23753–23759.Google Scholar
Svendsen, J.I., Briner, J.P., Mangerud, J., Young, N.E., (2015). Early break-up of the Norwegian Channel Ice Stream during the Last Glacial Maximum.. Quaternary Science Reviews 107, 231–242.Google Scholar
Thomas, G.S.P., Chiverrell, R.C., (2007). Structural and depositional evidence for repeated ice-marginal oscillation along the eastern margin of the Late Devensian Irish Sea Ice Stream.. Quaternary Science Reviews 26, 2375–2405.Google Scholar
Travis, C.B., (1944). The glacial history of the Berwyn hills, North Wales.. Proceedings of the Liverpool Geological Society 19, 14–28.Google Scholar
Whittow, J.B., Ball, D.F., (1970). North-west Wales. Lewis, C.A. The Glaciations of Wales and Adjoining Areas. Longman, London. 21–58.Google Scholar