The timing of glacier advances in the northern European Alps based on surface exposure dating with cosmogenic 10Be, 26Al, 36Cl, and 21Ne
Authors:
- Susan Ivy-OchsSISusan Ivy-Ochs
- Hanns KerschnerHKHanns Kerschner
- Anne ReutherARAnne Reuther
- Max MaischMMMax Maisch
- Rudolf SailerRSRudolf Sailer
- Joerg SchaeferJSJoerg Schaefer
- Peter W. KubikPKPeter W. Kubik
- Hans-Arno SynalHSHans-Arno Synal
- Christian SchlücHterCSChristian SchlücHter
- Ana María Alonso-ZarzaAAAna María Alonso-Zarza
- Lawrence H. TannerLTLawrence H. Tanner
- 1 January 2006
- book chapter
- Published by Geological Society of America
Abstract
Exposure dating of boulder and bedrock surfaces with 10Be, 21Ne, 26Al, and 36Cl allows us to constrain periods of glacier expansion in the European Alps. The age of 155 ka from a boulder of Alpine lithology located in the Jura Mountains (Switzerland) provides a minimum age for pre-LGM (Last Glacial Maximum), more extensive Alpine glaciations. During the LGM, glaciers expanded onto the foreland after 30 ka. By 21.1 ± 0.9 ka deglaciation had begun, and the Rhône Glacier abandoned the outer moraines. The age of 15.4 ± 1.4 ka provides a minimum age for formation of Gschnitz stadial moraines (Austria). They mark the first clear post-LGM readvance of mountain glaciers, when glacier termini were already situated well inside the mountains. Glacier advance at the onset of the Younger Dryas led to formation of Egesen I moraines, dated to 12.2 ± 1.0 ka at the Schönferwall site (Austria) and to 12.3 ± 1.5 ka at the outer moraine at Julier Pass (Switzerland). The age of 11.3 ± 0.9 ka for the inner moraine / rock glacier complex at Julier Pass corroborates the field evidence, which points to a marked increase in rock glacier activity and delayed moraine stabilization during the late Younger Dryas. An early Preboreal glacier advance, larger than the Little Ice Age advance(s) at 10.8 ± 1.0 ka, was recorded at Kartell cirque (Austria). A moraine doublet located a few hundred meters outside the A.D. 1850 moraines in Kromer Valley (Austria) was dated at 8.4 ± 0.7 ka. At least during termination 1, glacier volumes in the Alps varied in tune with climate oscillations, Heinrich event 1, the Younger Dryas cold phase, the Preboreal oscillation, and the 8.2 ka event.Keywords
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