Timing of glacial retreat in the Wicklow Mountains, Ireland, conditioned by glacier size and topography

Matt D. Tomkins, Jason M. Dortch, Philip D. Hughes, Jonny J. Huck, Toby N. Tonkin, Iestyn D. Barr

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Reconstructing the deglacial history of palaeo-glaciers provides vital information on retreat processes, information which can inform predictions of the future behaviour of many of the world's glaciers. On this basis, this paper presents 170 Schmidt Hammer exposure ages from moraine boulders and glacially sculpted bedrock to reveal the post-Last Glacial Maximum (LGM) history of the Wicklow Mountains, Ireland. These data suggest that large ice masses survived for 4–7 ka after retreat of the Irish Sea Ice Stream and were sustained by summit ice fields until ∼16.6 ka. Post-LGM retreat was driven by climate and involved numerous short-term ice front oscillations (≤1 ka), with widespread moraine deposition during Heinrich Stadial 1. In contrast, marked asynchroneity in the timing of Younger Dryas deglaciation is closely linked to snow redistribution which demonstrates the sensitivity of small cirque glaciers (≤1 km2) to local topography. This result has important implications for palaeoclimate reconstructions as cirque glacier dynamics may be (at least partly) decoupled from climate. This is further complicated by post-depositional processes which can result in moraine ages (e.g. 10Be) which post-date retreat. Future palaeoclimate studies should prioritize cirques where snow-contributing areas are small and where post-depositional disturbance of moraines is limited.

Original languageEnglish
Pages (from-to)611-623
Number of pages13
JournalJournal of Quaternary Science
Volume33
Issue number6
DOIs
StatePublished - Aug 2018

Bibliographical note

Funding Information:
M.T. is funded by a University of Manchester Presidents Doctoral Scholarship. Fieldwork was funded by the University of Manchester School of Environment, Education and Development Fieldwork Support Fund. J.M.D., P.D.H. and J.J.H. would like to thank the University of Manchester Research Stimulation Fund. We would like to thank David Tomkins for fieldwork support and John and Deirdre Lynham for their advice and hospitality. Thanks also go to Dr Derek Fabel for kindly providing unpublished calibration data for the LLPR and to two anonymous reviewers for their constructive reviews which greatly improved the manuscript.

Funding Information:
Acknowledgements. M.T. is funded by a University of Manchester Presidents Doctoral Scholarship. Fieldwork was funded by the University of Manchester School of Environment, Education and Development Fieldwork Support Fund. J.M.D., P.D.H. and J.J.H. would like to thank the University of Manchester Research Stimulation Fund. We would like to thank David Tomkins for fieldwork support and John and Deirdre Lynham for their advice and hospitality. Thanks also go to Dr Derek Fabel for kindly providing unpublished calibration data for the LLPR and to two anonymous reviewers for their constructive reviews which greatly improved the manuscript.

Publisher Copyright:
Copyright © 2018 John Wiley & Sons, Ltd.

Keywords

  • Be dating
  • glacier chronology
  • Ireland
  • Schmidt Hammer exposure dating (SHED)
  • topographic controls
  • Wicklow

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Earth and Planetary Sciences (miscellaneous)
  • Paleontology

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