Mechanical forcing of water pressure in a hydraulically isolated reach beneath Western Greenland's ablation zone
A suite of surface and basal measurements during and after borehole drilling is used to perform in situ investigation of the local basal drainage system and pressure forcing in western Greenland. Drill and borehole water temperature were monitored during borehole drilling, which was performed with d...
Published in: | Annals of Glaciology |
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Language: | English |
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Cambridge University Press
2016
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Online Access: | https://doi.org/10.1017/aog.2016.5 https://doaj.org/article/825e5d27b7bf4743825880d7aee9fcf0 |
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ftdoajarticles:oai:doaj.org/article:825e5d27b7bf4743825880d7aee9fcf0 2023-05-15T13:29:35+02:00 Mechanical forcing of water pressure in a hydraulically isolated reach beneath Western Greenland's ablation zone Toby W. Meierbachtol Joel T. Harper Neil F. Humphrey Patrick J. Wright 2016-07-01T00:00:00Z https://doi.org/10.1017/aog.2016.5 https://doaj.org/article/825e5d27b7bf4743825880d7aee9fcf0 EN eng Cambridge University Press https://www.cambridge.org/core/product/identifier/S0260305516000057/type/journal_article https://doaj.org/toc/0260-3055 https://doaj.org/toc/1727-5644 doi:10.1017/aog.2016.5 0260-3055 1727-5644 https://doaj.org/article/825e5d27b7bf4743825880d7aee9fcf0 Annals of Glaciology, Vol 57, Pp 62-70 (2016) glacier hydrology subglacial processes Meteorology. Climatology QC851-999 article 2016 ftdoajarticles https://doi.org/10.1017/aog.2016.5 2023-03-12T01:31:57Z A suite of surface and basal measurements during and after borehole drilling is used to perform in situ investigation of the local basal drainage system and pressure forcing in western Greenland. Drill and borehole water temperature were monitored during borehole drilling, which was performed with dyed hot water. After drilling, borehole water pressure and basal dye concentration were measured concurrently with positions in a GPS strain diamond at the surface. Water pressure exhibited diurnal changes in antiphase with velocity. Dye monitoring in the borehole revealed stagnant basal water for nearly 2 weeks. The interpretation of initial connection to an isolated basal cavity is corroborated by the thermal signature of borehole water during hot water drilling. Measurement-based estimates of cavity size are on the order of cubic meters, and analysis indicates that small changes in its volume could induce the observed pressure variations. It is found that longitudinal coupling effects are unable to force necessary volume changes at the site. Sliding-driven basal cavity opening and elastic uplift from load transfer are plausible mechanisms controlling pressure variations. Elastic uplift requires forcing from a hydraulically connected reach, which observations suggest must be relatively small and in close proximity to the isolated cavity. Article in Journal/Newspaper Annals of Glaciology glacier Greenland Directory of Open Access Journals: DOAJ Articles Greenland Annals of Glaciology 57 72 62 70 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
glacier hydrology subglacial processes Meteorology. Climatology QC851-999 |
spellingShingle |
glacier hydrology subglacial processes Meteorology. Climatology QC851-999 Toby W. Meierbachtol Joel T. Harper Neil F. Humphrey Patrick J. Wright Mechanical forcing of water pressure in a hydraulically isolated reach beneath Western Greenland's ablation zone |
topic_facet |
glacier hydrology subglacial processes Meteorology. Climatology QC851-999 |
description |
A suite of surface and basal measurements during and after borehole drilling is used to perform in situ investigation of the local basal drainage system and pressure forcing in western Greenland. Drill and borehole water temperature were monitored during borehole drilling, which was performed with dyed hot water. After drilling, borehole water pressure and basal dye concentration were measured concurrently with positions in a GPS strain diamond at the surface. Water pressure exhibited diurnal changes in antiphase with velocity. Dye monitoring in the borehole revealed stagnant basal water for nearly 2 weeks. The interpretation of initial connection to an isolated basal cavity is corroborated by the thermal signature of borehole water during hot water drilling. Measurement-based estimates of cavity size are on the order of cubic meters, and analysis indicates that small changes in its volume could induce the observed pressure variations. It is found that longitudinal coupling effects are unable to force necessary volume changes at the site. Sliding-driven basal cavity opening and elastic uplift from load transfer are plausible mechanisms controlling pressure variations. Elastic uplift requires forcing from a hydraulically connected reach, which observations suggest must be relatively small and in close proximity to the isolated cavity. |
format |
Article in Journal/Newspaper |
author |
Toby W. Meierbachtol Joel T. Harper Neil F. Humphrey Patrick J. Wright |
author_facet |
Toby W. Meierbachtol Joel T. Harper Neil F. Humphrey Patrick J. Wright |
author_sort |
Toby W. Meierbachtol |
title |
Mechanical forcing of water pressure in a hydraulically isolated reach beneath Western Greenland's ablation zone |
title_short |
Mechanical forcing of water pressure in a hydraulically isolated reach beneath Western Greenland's ablation zone |
title_full |
Mechanical forcing of water pressure in a hydraulically isolated reach beneath Western Greenland's ablation zone |
title_fullStr |
Mechanical forcing of water pressure in a hydraulically isolated reach beneath Western Greenland's ablation zone |
title_full_unstemmed |
Mechanical forcing of water pressure in a hydraulically isolated reach beneath Western Greenland's ablation zone |
title_sort |
mechanical forcing of water pressure in a hydraulically isolated reach beneath western greenland's ablation zone |
publisher |
Cambridge University Press |
publishDate |
2016 |
url |
https://doi.org/10.1017/aog.2016.5 https://doaj.org/article/825e5d27b7bf4743825880d7aee9fcf0 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Annals of Glaciology glacier Greenland |
genre_facet |
Annals of Glaciology glacier Greenland |
op_source |
Annals of Glaciology, Vol 57, Pp 62-70 (2016) |
op_relation |
https://www.cambridge.org/core/product/identifier/S0260305516000057/type/journal_article https://doaj.org/toc/0260-3055 https://doaj.org/toc/1727-5644 doi:10.1017/aog.2016.5 0260-3055 1727-5644 https://doaj.org/article/825e5d27b7bf4743825880d7aee9fcf0 |
op_doi |
https://doi.org/10.1017/aog.2016.5 |
container_title |
Annals of Glaciology |
container_volume |
57 |
container_issue |
72 |
container_start_page |
62 |
op_container_end_page |
70 |
_version_ |
1766001349688819712 |