Last Glacial Maximum cirque glaciation in Ireland and implications for reconstructions of the Irish Ice Sheet

Aaron M. Barth, Peter U. Clark, Jorie Clark, A. Marshall McCabe, Marc Caffee

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Reconstructions of the extent and height of the Irish Ice Sheet (IIS) during the Last Glacial Maximum (LGM, ~19-26 ka) are widely debated, in large part due to limited age constraints on former ice margins and due to uncertainties in the origin of the trimlines. A key area is southwestern Ireland, where various LGM reconstructions range from complete coverage by a contiguous IIS that extends to the continental shelf edge to a separate, more restricted southern-sourced Kerry-Cork Ice Cap (KCIC). We present new 10Be surface exposure ages from two moraines in a cirque basin in the Macgillycuddy's Reeks that provide a unique and unequivocal constraint on ice thickness for this region. Nine 10Be ages from an outer moraine yield a mean age of 24.5 ± 1.4 ka while six ages from an inner moraine yield a mean age of 20.4 ± 1.2 ka. These ages show that the northern flanks of the Macgillycuddy's Reeks were not covered by the IIS or a KCIC since at least 24.5 ± 1.4 ka. If there was more extensive ice coverage over the Macgillycuddy's Reeks during the LGM, it occurred prior to our oldest ages.

Original languageEnglish
Pages (from-to)85-93
Number of pages9
JournalQuaternary Science Reviews
Volume141
Early online date18 Apr 2016
DOIs
Publication statusPublished - 1 Jun 2016

Keywords

  • Cirque
  • Cosmogenic nuclide
  • Ireland
  • Last Glacial Maximum
  • Paleoclimatology
  • Quaternary

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