Universität zu Köln

Marr, Philipp ORCID: 0000-0002-8037-1017, Winkler, Stefan, Binnie, Steven A. and Loeffler, Joerg (2019). Be-10-based exploration of the timing of deglaciation in two selected areas of southern Norway. E G Quatern. Sci. J., 68 (2). S. 165 - 177. GOTTINGEN: COPERNICUS GESELLSCHAFT MBH. ISSN 2199-9090

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Abstract

We present new Be-10 surface exposure ages from two selected locations in southern Norway. A total of five Be-10 samples allow a first assessment of local deglaciation dynamics of the Scandinavian Ice Sheet at Dalsnibba (1476 ma.s.l.) in southwestern Norway. The bedrock ages from the summit of Dalsnibba range from 13.3 +/- 0.6 to 12.7 +/- 0.5 ka and probably indicate the onset of deglaciation as a glacially transported boulder age (16.5 +/- 0.6 ka) from the same elevation likely shows inheritance. These ages indicate initial deglaciation commencing at the end of the Bolling-Allerod interstadial (similar to 14.7-12.9 kyr BP) and ice-free conditions at Dalsnibba's summit during the Younger Dryas. Bedrock samples at lower elevations imply vertical ice surface lowering down to 1334 ma.s.l. at 10.3 +/- 0.5 ka and a longer overall period of downwasting than previously assumed. Two further Be-10 samples add to the existing chronology at Blaho (1617 ma.s.l.) in south-central Norway. The Be-10 erratic boulder sample on the summit of Blaho sample yields 20.9 +/- 0.8 ka, whereas a Be-10 age of 46.4 +/- 1.7 ka for exposed summit bedrock predates the Late Weichselian Maximum. This anomalously old bedrock age infers inherited cosmogenic nuclide concentrations and suggests low erosive cold-based ice cover during the Last Glacial Maximum. However, due to possible effects of cryoturbation and frost heave processes affecting the erratic boulder age and insufficient numbers of Be-10 samples, the glaciation history on Blaho cannot conclusively be resolved. Comparing the different timing of deglaciation at both locations in a rather short west-east distance demonstrates the complex dynamics of deglaciation in relation to other areas in southern Norway.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Marr, Philipp UNSPECIFIED orcid.org/0000-0002-8037-1017 UNSPECIFIED Winkler, Stefan UNSPECIFIED UNSPECIFIED UNSPECIFIED Binnie, Steven A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Loeffler, Joerg UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-134517
DOI:	10.5194/egqsj-68-165-2019
Journal or Publication Title:	E G Quatern. Sci. J.
Volume:	68
Number:	2
Page Range:	S. 165 - 177
Date:	2019
Publisher:	COPERNICUS GESELLSCHAFT MBH
Place of Publication:	GOTTINGEN
ISSN:	2199-9090
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language Geology Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/13451