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GEOREF RECORD

Constraining landscape history and glacial erosivity using paired cosmogenic nuclides in Upernavik, northwest Greenland

Lee B. Corbett, Paul R. Bierman, Joseph A. Graly, Thomas A. Neumann and Dylan H. Rood
Constraining landscape history and glacial erosivity using paired cosmogenic nuclides in Upernavik, northwest Greenland
Geological Society of America Bulletin (July 2013) 125 (9-10): 1539-1553

Abstract

High-latitude landscape evolution processes have the potential to preserve old, relict surfaces through burial by cold-based, nonerosive glacial ice. To investigate landscape history and age in the high Arctic, we analyzed in situ cosmogenic (super 10) Be and (super 26) Al in 33 rocks from Upernavik, northwest Greenland. We sampled adjacent bedrock-boulder pairs along a 100 km transect at elevations up to 1000 m above sea level. Bedrock samples gave significantly older apparent exposure ages than corresponding boulder samples, and minimum limiting ages increased with elevation. Two-isotope calculations ( (super 26) Al/ (super 10) Be) on 20 of the 33 samples yielded minimum limiting exposure durations up to 112 k.y., minimum limiting burial durations up to 900 k.y., and minimum limiting total histories up to 990 k.y. The prevalence of (super 10) Be and (super 26) Al inherited from previous periods of exposure, especially in bedrock samples at high elevation, indicates that these areas record long and complex surface exposure histories, including significant periods of burial with little subglacial erosion. The long total histories suggest that these high-elevation surfaces were largely preserved beneath cold-based, nonerosive ice or snowfields for at least the latter half of the Quaternary. Because of high concentrations of inherited nuclides, only the six youngest boulder samples appear to record the timing of ice retreat. These six samples suggest deglaciation of the Upernavik coast at 11.3 + or - 0.5 ka (average + or - 1 standard deviation). There is no difference in deglaciation age along the 100 km sample transect, indicating that the ice-marginal position retreated rapidly at rates of approximately 120 m yr (super -1) .


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 125
Serial Issue: 9-10
Title: Constraining landscape history and glacial erosivity using paired cosmogenic nuclides in Upernavik, northwest Greenland
Affiliation: University of Vermont, Department of Geology, Burlington, VT, United States
Pages: 1539-1553
Published: 20130723
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 85
Accession Number: 2013-069350
Categories: Quaternary geologyGeochronology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2013264
Illustration Description: illus. incl. 2 tables, sketch map
N73°00'00" - N73°00'00", W55°00'00" - W55°00'00"
Secondary Affiliation: Scottish Universities Environmental Research Centre, GBR, United Kingdom
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201341
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