Internal structure of the Green Lake 5 rock glacier, Colorado Front Range, USA
ABSTRACT Information about the internal structure of rock glaciers is needed to understand their reaction to ongoing climate warming. Three different geophysical techniques—shallow seismic refraction, ground‐penetrating radar (GPR) and electrical resistivity tomography—were used to develop a detaile...
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crwiley:10.1002/ppp.706 2024-06-02T08:08:03+00:00 Internal structure of the Green Lake 5 rock glacier, Colorado Front Range, USA Leopold, M. Williams, M.W. Caine, N. Völkel, J. Dethier, D. 2011 http://dx.doi.org/10.1002/ppp.706 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fppp.706 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ppp.706 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Permafrost and Periglacial Processes volume 22, issue 2, page 107-119 ISSN 1045-6740 1099-1530 journal-article 2011 crwiley https://doi.org/10.1002/ppp.706 2024-05-03T11:10:35Z ABSTRACT Information about the internal structure of rock glaciers is needed to understand their reaction to ongoing climate warming. Three different geophysical techniques—shallow seismic refraction, ground‐penetrating radar (GPR) and electrical resistivity tomography—were used to develop a detailed subsurface model of the Green Lake 5 rock glacier in the Colorado Front Range, USA. Below a thin zone of fine sediments and soils (0.7 – 1‐m thickness; 0 – 20 kΩm and 320 – 370 m s −1 ), a 1 – 3‐m thick zone with low p‐wave velocities (790 – 820 m s −1 ) and high electrical resistivity (20 – 100 kΩm) is interpreted as the ice‐free, blocky active layer with large void spaces. The data corroborate strong reflections of the GPR signals which travel at this depth at 0.11 m ns −1 . A third layer that extends from depths of 1 – 3 m to about 5 m is characterised by lower electric resistivities (5 – 20 kΩm) and has lower electromagnetic wave velocities (0.65 m ns −1 ), representing unfrozen, finer and wetter sediments. At around 5‐m depth, the measured physical parameters change drastically (vp = 3200 – 3300 m s −1 , 50 – 150 kΩm, vGPR = 0.15 m ns −1 ), showing an ice‐rich permafrost zone above the bedrock. This model of the internal structure was used to evaluate an existing hydrological flowpath model based on the hydrochemical properties of water outflow from the rock glacier. Copyright © 2011 John Wiley & Sons, Ltd. Article in Journal/Newspaper Ice permafrost Permafrost and Periglacial Processes Wiley Online Library Permafrost and Periglacial Processes 22 2 107 119 |
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Wiley Online Library |
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crwiley |
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English |
description |
ABSTRACT Information about the internal structure of rock glaciers is needed to understand their reaction to ongoing climate warming. Three different geophysical techniques—shallow seismic refraction, ground‐penetrating radar (GPR) and electrical resistivity tomography—were used to develop a detailed subsurface model of the Green Lake 5 rock glacier in the Colorado Front Range, USA. Below a thin zone of fine sediments and soils (0.7 – 1‐m thickness; 0 – 20 kΩm and 320 – 370 m s −1 ), a 1 – 3‐m thick zone with low p‐wave velocities (790 – 820 m s −1 ) and high electrical resistivity (20 – 100 kΩm) is interpreted as the ice‐free, blocky active layer with large void spaces. The data corroborate strong reflections of the GPR signals which travel at this depth at 0.11 m ns −1 . A third layer that extends from depths of 1 – 3 m to about 5 m is characterised by lower electric resistivities (5 – 20 kΩm) and has lower electromagnetic wave velocities (0.65 m ns −1 ), representing unfrozen, finer and wetter sediments. At around 5‐m depth, the measured physical parameters change drastically (vp = 3200 – 3300 m s −1 , 50 – 150 kΩm, vGPR = 0.15 m ns −1 ), showing an ice‐rich permafrost zone above the bedrock. This model of the internal structure was used to evaluate an existing hydrological flowpath model based on the hydrochemical properties of water outflow from the rock glacier. Copyright © 2011 John Wiley & Sons, Ltd. |
format |
Article in Journal/Newspaper |
author |
Leopold, M. Williams, M.W. Caine, N. Völkel, J. Dethier, D. |
spellingShingle |
Leopold, M. Williams, M.W. Caine, N. Völkel, J. Dethier, D. Internal structure of the Green Lake 5 rock glacier, Colorado Front Range, USA |
author_facet |
Leopold, M. Williams, M.W. Caine, N. Völkel, J. Dethier, D. |
author_sort |
Leopold, M. |
title |
Internal structure of the Green Lake 5 rock glacier, Colorado Front Range, USA |
title_short |
Internal structure of the Green Lake 5 rock glacier, Colorado Front Range, USA |
title_full |
Internal structure of the Green Lake 5 rock glacier, Colorado Front Range, USA |
title_fullStr |
Internal structure of the Green Lake 5 rock glacier, Colorado Front Range, USA |
title_full_unstemmed |
Internal structure of the Green Lake 5 rock glacier, Colorado Front Range, USA |
title_sort |
internal structure of the green lake 5 rock glacier, colorado front range, usa |
publisher |
Wiley |
publishDate |
2011 |
url |
http://dx.doi.org/10.1002/ppp.706 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fppp.706 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ppp.706 |
genre |
Ice permafrost Permafrost and Periglacial Processes |
genre_facet |
Ice permafrost Permafrost and Periglacial Processes |
op_source |
Permafrost and Periglacial Processes volume 22, issue 2, page 107-119 ISSN 1045-6740 1099-1530 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/ppp.706 |
container_title |
Permafrost and Periglacial Processes |
container_volume |
22 |
container_issue |
2 |
container_start_page |
107 |
op_container_end_page |
119 |
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1800753203642368000 |