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Crystal growth of air hydrates over 720 ka in Dome Fuji (Antarctica) ice cores: microscopic observations of morphological changes below 2000 m depth

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Title: Crystal growth of air hydrates over 720 ka in Dome Fuji (Antarctica) ice cores: microscopic observations of morphological changes below 2000 m depth
Authors: Uchida, Tsutomu Browse this author →KAKEN DB
Miyamoto, Atsushi Browse this author →KAKEN DB
Shin'yama, Atsushi Browse this author
Hondoh, Takeo Browse this author →KAKEN DB
Issue Date: Dec-2011
Publisher: International Glaciological Society
Journal Title: Journal of Glaciology
Volume: 57
Issue: 206
Start Page: 1017
End Page: 1026
Publisher DOI: 10.3189/002214311798843296
Abstract: Air-hydrate crystals store most of the ancient air contained in deep ice sheets. We carried out microscopic observations of air-hydrate crystals below 2000 m depth within the ice core from Dome Fuji, Antarctica, to obtain their number and size distributions. We found that the number density continuously decreased with depth, whereas the average size increased, in contrast to findings from shallower depths. In addition, the characteristic perturbations in both number density and average size distribution with climatic changes almost disappeared, although they are clearly observed in shallow cores. These results indicate that the air-hydrate crystals grow considerably in deeper parts of the ice sheet, and this growth is accompanied by the diffusion of air molecules in the ice. The permeation coefficient of the air molecules in the ice sheet was estimated from the geometric parameters of the air-hydrate distributions. This is the first practical evidence comparable to the previous model estimations. It allows us to evaluate the impacts of the air-molecule migration in the ice sheet on the paleoclimatic information recorded in the deep ice cores.
Rights: © 2011 International Glaciological Society
Relation: http://www.igsoc.org/
Type: article
URI: http://hdl.handle.net/2115/49347
Appears in Collections:工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

Submitter: 内田 努

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