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Interpreting ancient ice in a shallow ice core from the South Yamato (Antarctica) blue ice area using flow modeling and compositional matching to deep ice cores

Moore, John C.; Nishio, Fumihiko; Fujita, Shuji; Narita, Hideki; Pasteur, Elizabeth; Grinsted, Aslak; Sinisalo, Anna; Maeno, Norikazu. 2006 Interpreting ancient ice in a shallow ice core from the South Yamato (Antarctica) blue ice area using flow modeling and compositional matching to deep ice cores. Journal of Geophysical Research, 111 (D16), D16302. 17, pp. 10.1029/2005JD006343

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Abstract/Summary

We explore methods of dating a 101 m ice core from a bare ice ablation area in the Yamato Mountains, Dronning Maud Land, East Antarctica. There are two unknowns, the age of the ice at the surface and the age spanned by the core. The ice crystal growth rate was used to estimate the age span of the core at about 5 kyr. CO2, CH4 and N2O data on the core were compared with well-dated records from deep cores, leading to two plausible matches, both within isotope stage C. Detailed comparison of high-resolution DEP records from this core and the Dome Fuji core support the 55–61 kyr BP fit best. Oxygen isotope values in the core were then used to constrain the source elevation of the snow in the core, and hence the velocities in a simple flow line model. We inverted the ice core surface age, age span and origin site and their confidence intervals in a sensitivity study of flow model parameter space. The flow line model predicts good matches to the core by reducing glacial flow rates to 70% of present-day, accumulation rates by 45% with 10% confidence intervals. The modeled surface age for the whole meteorite field yields maximum surface ages of about 90 kyr, which is consistent with known, but poorly constrained, tephra dating, meteorite terrestrial ages and the frequency of meteorite discoveries. This approach can be used quite generally to link deep ice cores to surface outcrops on blue ice fields

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1029/2005JD006343
Programmes: BAS Programmes > Global Science in the Antarctic Context (2005-2009) > Climate and Chemistry - Forcings and Phasings in the Earth System
ISSN: 0148-0227
Additional Information. Not used in RCUK Gateway to Research.: Full text not available from this repository
Additional Keywords: Ice cores
NORA Subject Terms: Glaciology
Date made live: 21 Aug 2007 15:01
URI: http://nora.nerc.ac.uk/id/eprint/87

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