Cryostratigraphy and the Sublimation Unconformity in Permafrost from an Ultraxerous Environment, University Valley, McMurdo Dry Valleys of Antarctica
The cryostratigraphy of permafrost in ultraxerous environments is poorly known. In this study, icy permafrost cores from University Valley (McMurdo Dry Valleys, Antarctica) were analyzed for sediment properties, ground-ice content, types and distribution of cryostructures, and presence of unconformi...
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ftnasantrs:oai:casi.ntrs.nasa.gov:20170009829 2023-05-15T13:35:23+02:00 Cryostratigraphy and the Sublimation Unconformity in Permafrost from an Ultraxerous Environment, University Valley, McMurdo Dry Valleys of Antarctica Davila, Alfonso Fortier, Daniel Pollard, Wayne McKay, Christopher P. Lapalme, Caitlin M. Lacelle, Denis Unclassified, Unlimited, Publicly available May 29, 2017 application/pdf http://hdl.handle.net/2060/20170009829 unknown Document ID: 20170009829 http://hdl.handle.net/2060/20170009829 Copyright, Use by or on behalf of the U.S. Government permitted CASI Lunar and Planetary Science and Exploration ARC-E-DAA-TN42142 Permafrost and Periglacial Processes (ISSN 1045-6740) (e-ISSN 1099-1530); 28; 4; 649–662 2017 ftnasantrs 2019-07-20T23:25:14Z The cryostratigraphy of permafrost in ultraxerous environments is poorly known. In this study, icy permafrost cores from University Valley (McMurdo Dry Valleys, Antarctica) were analyzed for sediment properties, ground-ice content, types and distribution of cryostructures, and presence of unconformities. No active layer exists in the valley, but the ice table, a sublimation unconformity, ranges from 0 to 60 cm depth. The sediments are characterized as a medium sand, which classifies them as low to non-frost susceptible. Computed tomography (CT) scan images of the icy permafrost cores revealed composite cryostructures that included the structureless, porous visible, suspended and crustal types. These cryostructures were observed irrespective of ground-ice origin (vapour deposited and freezing of snow meltwater), suggesting that the type and distribution of cryostructures could not be used as a proxy to infer the mode of emplacement of ground ice. Volumetric ice content derived from the CT scan images underestimated measured volumetric ice content, but approached measured excess ice content. A palaeo-sublimation unconformity could not be detected from a change in cryostructures, but could be inferred from an increase in ice content at the maximum predicted ice table depth. This study highlights some of the unique ground-ice processes and cryostructures in ultraxerous environments. Other/Unknown Material Antarc* Antarctica Ice McMurdo Dry Valleys permafrost NASA Technical Reports Server (NTRS) McMurdo Dry Valleys University Valley ENVELOPE(160.667,160.667,-77.867,-77.867) |
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Open Polar |
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NASA Technical Reports Server (NTRS) |
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ftnasantrs |
language |
unknown |
topic |
Lunar and Planetary Science and Exploration |
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Lunar and Planetary Science and Exploration Davila, Alfonso Fortier, Daniel Pollard, Wayne McKay, Christopher P. Lapalme, Caitlin M. Lacelle, Denis Cryostratigraphy and the Sublimation Unconformity in Permafrost from an Ultraxerous Environment, University Valley, McMurdo Dry Valleys of Antarctica |
topic_facet |
Lunar and Planetary Science and Exploration |
description |
The cryostratigraphy of permafrost in ultraxerous environments is poorly known. In this study, icy permafrost cores from University Valley (McMurdo Dry Valleys, Antarctica) were analyzed for sediment properties, ground-ice content, types and distribution of cryostructures, and presence of unconformities. No active layer exists in the valley, but the ice table, a sublimation unconformity, ranges from 0 to 60 cm depth. The sediments are characterized as a medium sand, which classifies them as low to non-frost susceptible. Computed tomography (CT) scan images of the icy permafrost cores revealed composite cryostructures that included the structureless, porous visible, suspended and crustal types. These cryostructures were observed irrespective of ground-ice origin (vapour deposited and freezing of snow meltwater), suggesting that the type and distribution of cryostructures could not be used as a proxy to infer the mode of emplacement of ground ice. Volumetric ice content derived from the CT scan images underestimated measured volumetric ice content, but approached measured excess ice content. A palaeo-sublimation unconformity could not be detected from a change in cryostructures, but could be inferred from an increase in ice content at the maximum predicted ice table depth. This study highlights some of the unique ground-ice processes and cryostructures in ultraxerous environments. |
format |
Other/Unknown Material |
author |
Davila, Alfonso Fortier, Daniel Pollard, Wayne McKay, Christopher P. Lapalme, Caitlin M. Lacelle, Denis |
author_facet |
Davila, Alfonso Fortier, Daniel Pollard, Wayne McKay, Christopher P. Lapalme, Caitlin M. Lacelle, Denis |
author_sort |
Davila, Alfonso |
title |
Cryostratigraphy and the Sublimation Unconformity in Permafrost from an Ultraxerous Environment, University Valley, McMurdo Dry Valleys of Antarctica |
title_short |
Cryostratigraphy and the Sublimation Unconformity in Permafrost from an Ultraxerous Environment, University Valley, McMurdo Dry Valleys of Antarctica |
title_full |
Cryostratigraphy and the Sublimation Unconformity in Permafrost from an Ultraxerous Environment, University Valley, McMurdo Dry Valleys of Antarctica |
title_fullStr |
Cryostratigraphy and the Sublimation Unconformity in Permafrost from an Ultraxerous Environment, University Valley, McMurdo Dry Valleys of Antarctica |
title_full_unstemmed |
Cryostratigraphy and the Sublimation Unconformity in Permafrost from an Ultraxerous Environment, University Valley, McMurdo Dry Valleys of Antarctica |
title_sort |
cryostratigraphy and the sublimation unconformity in permafrost from an ultraxerous environment, university valley, mcmurdo dry valleys of antarctica |
publishDate |
2017 |
url |
http://hdl.handle.net/2060/20170009829 |
op_coverage |
Unclassified, Unlimited, Publicly available |
long_lat |
ENVELOPE(160.667,160.667,-77.867,-77.867) |
geographic |
McMurdo Dry Valleys University Valley |
geographic_facet |
McMurdo Dry Valleys University Valley |
genre |
Antarc* Antarctica Ice McMurdo Dry Valleys permafrost |
genre_facet |
Antarc* Antarctica Ice McMurdo Dry Valleys permafrost |
op_source |
CASI |
op_relation |
Document ID: 20170009829 http://hdl.handle.net/2060/20170009829 |
op_rights |
Copyright, Use by or on behalf of the U.S. Government permitted |
_version_ |
1766064975488483328 |