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Cosmogenic nuclide dating (10Be and 26Al) is applied to boulders on two moraine ridges at the typesite of the early-Holocene Erdalen Event, southern Norway, dated previously using radiocarbon. Quartz-rich rock samples yielded 10Be age estimates between 9.8 ± 1.2 and 10.1 ± 1.1 ka (external uncertainties, ± 1σ), with an average of 9.95 ka. These age estimates are statistically indistinguishable from the independent radiocarbon age estimate. 26Al age estimates, which ranged from 9.4 ± 1.1 to 11.2 ± 1.3 ka and averaged 10.1 ka, provided useful corroboration of the 10Be results. Although current levels of precision and accuracy are insufficient to distinguish between the ages of younger inner and older outer moraines, the results demonstrate the potential of the method at suitable sites where radiocarbon dating is not possible. Several environmental factors, including effective glacial erosion, stability of moraine slopes, snow cover of sufficiently shallow depth and short duration, and the absence of colluvial contamination, appear to have been instrumental in the success of applying the method at this site. The results confirm the timing and extent of the Erdalen Event in southern Norway with implications for Holocene glacier chronology and millennial-scale climatic variability. [ABSTRACT FROM AUTHOR]

Lichenometric evidence and Schmidt hammer R-values are used to date Holocene moraine sequences in front of six high-altitude (> 1500 m) glaciers in Breheimen, central southern Norway. At three glacier forelands with southerly aspects (Høgsetbreen, Vestre Høybre and Østre Høybre), relatively small (≤ 4 m high) discrete boulder moraine ridges are shown to date from the 'Little Ice Age'. The remaining three glaciers (Østre Tundradalskyrkjabre, Nordre Tundradalskyrkjabre and Hestdalshøgdibreen), with northerly or easterly aspects and large, multiridged, rampart-like moraine complexes (15–30 m), thought to be ice-cored and of the 'push-deformation' type, lie above the local altitudinal limit of permafrost. Negatively skewed R-value distributions from these moraine complexes provide critical evidence for pre-'Little Ice Age' glacier expansion as they indicate the survival of long-weathered boulders on moraine surfaces where late-lying snow may reduce or prevent lichen growth. Formation of the moraine complexes appears to have begun in Preboreal times, most likely during the Erdalen Event, but much of their present character was determined by repeated Neoglacial glacier expansion, moraine deformation and ridge formation in the late Holocene, culminating in the 'Little Ice Age' readvance. [ABSTRACT FROM AUTHOR]

Following the Younger Dryas, the first evidence of glacial activity in southern Norway in response to climatic change occurred during the early Holocene, when terminal moraines from the Erdalen Event formed beyond the position of later 'Little Ice Age' moraines. In front of present outlet glaciers on both sides of the Jostedalsbreen ice cap, sets of pre-'Little Ice Age' marginal moraines have been morphostratigraphically correlated with the Erdalen Event. The lithostratigraphy in a peat bog at Hellemyrane in Jostedalen, western Norway, provides firm evidence for a two-phase Erdalen Event associated with two glacier readvances of Nigardsbreen at the Preboreal/Boreal transition. Radiocarbon dates from the peat bog give age estimates for the two phases: the first Erdalen Event readvance took place between 10 100 and 10 050 cal. BP, while the second occurred close to 9700 cal. BP. The lowering of the equilibrium-line altitude (ELA) during these readvances is estimated using the 'Little Ice Age' ratio (LR) approach to be about 230 m and 215 m, respectively. The first readvance is attributed to an increase in winter precipitation, while the second readvance may have been primarily caused by a marked drop in summer temperature which reactivated already existing ice masses. [ABSTRACT FROM AUTHOR]