Abstract
We report 80 10Be ages on 14 moraines from Irish cirques that show a previously unrecognized signal of at least eight millennial-scale fluctuations between 24.5±0.7 ka and 11.0±0.3 ka. Several moraine ages may be correlative with abrupt warming at the onset of the Bølling (14.7 ka) and the end of the Younger Dryas (11.7 ka), suggesting a forced response. Our ages also identify glacier fluctuations that occurred when regional temperatures were relatively stable. This finding is consistent with modeling results showing several hundred-meter-scale glacier fluctuations in response to interannual variability. At the same time, our composite record of cirque-glacier average equilibrium line altitudes (ELAs) shows a response to warming due to increasing greenhouse gases and summer insolation modulated by abrupt climate changes. Our new 10Be chronology thus records both forced and unforced millennial-scale glacier fluctuations superimposed on a lower frequency ELA signal of forced response to climate change.
Original language | English |
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Pages (from-to) | 151-154 |
Number of pages | 4 |
Journal | Geology |
Volume | 46 |
Issue number | 2 |
Early online date | 12 Dec 2017 |
DOIs | |
Publication status | Published (in print/issue) - 28 Feb 2018 |
Keywords
- Glacier
- Cirque
- Glaciation
- Ice Sheet
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Paul Dunlop
- School of Geog & Environmental Scs - Professor of Glaciology
- Faculty Of Life & Health Sciences - Research Director (Geography and Environmental Studies)
Person: Academic