Heat Flow and Hydrologic Characteristics at the AND-1B borehole, ANDRILL McMurdo Ice Shelf Project, Antarctica
The Antarctic Drilling Program (ANDRILL) successfully drilled and cored a borehole, AND-1B, beneath the McMurdo Ice Shelf and into a flexural moat basin that surrounds Ross Island. Total drilling depth reached 1285 m below sea floor (mbsf) with 98 percent core recovery for the detailed study of glac...
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ftunivnebraskali:oai:digitalcommons.unl.edu:usgsstaffpub-1356 2023-11-12T04:04:01+01:00 Heat Flow and Hydrologic Characteristics at the AND-1B borehole, ANDRILL McMurdo Ice Shelf Project, Antarctica Morin, Roger H Williams, Trevor Henrys, Stuart A Magens, Diana Niessen, Frank Hansaraj, Dhiresh 2010-01-01T08:00:00Z application/pdf https://digitalcommons.unl.edu/usgsstaffpub/347 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1356/viewcontent/Morin_GEOSPHERE_2010_Heat_Flow_and_hydrologic.pdf unknown DigitalCommons@University of Nebraska - Lincoln https://digitalcommons.unl.edu/usgsstaffpub/347 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1356/viewcontent/Morin_GEOSPHERE_2010_Heat_Flow_and_hydrologic.pdf USGS Staff -- Published Research Earth Sciences text 2010 ftunivnebraskali 2023-10-30T10:45:15Z The Antarctic Drilling Program (ANDRILL) successfully drilled and cored a borehole, AND-1B, beneath the McMurdo Ice Shelf and into a flexural moat basin that surrounds Ross Island. Total drilling depth reached 1285 m below sea floor (mbsf) with 98 percent core recovery for the detailed study of glacier dynamics. With the goal of obtaining complementary information regarding heat fl ow and permeability, which is vital to understanding the nature of marine hydrogeologic systems, a succession of three temperature logs was recorded over a five day span to monitor the gradual thermal recovery toward equilibrium conditions. These data were extrapolated to true, undisturbed temperatures, and they define a linear geothermal gradient of 76.7 K/km from the seafloor to 647 mbsf. Bulk thermal conductivities of the sedimentary rocks were derived from empirical mixing models and density measurements performed on core, and an average value of 1.5 W/mK ± 10 percent was determined. The corresponding estimate of heat fl ow at this site is 115 mW/m2. This value is relatively high but is consistent with other elevated heat-fl ow data associated with the Erebus Volcanic Province. Information regarding the origin and frequency of pathways for subsurface fluid flow is gleaned from drillers’ records, complementary geophysical logs, and core descriptions. Only two prominent permeable zones are identified and these correspond to two markedly different features within the rift basin; one is a distinct lithostratigraphic subunit consisting of a thin lava fl ow and the other is a heavily fractured interval within a single thick subunit. Text Antarc* Antarctic Antarctica Ice Shelf McMurdo Ice Shelf Ross Island University of Nebraska-Lincoln: DigitalCommons@UNL Antarctic The Antarctic Ross Island McMurdo Ice Shelf ENVELOPE(166.500,166.500,-78.000,-78.000) |
institution |
Open Polar |
collection |
University of Nebraska-Lincoln: DigitalCommons@UNL |
op_collection_id |
ftunivnebraskali |
language |
unknown |
topic |
Earth Sciences |
spellingShingle |
Earth Sciences Morin, Roger H Williams, Trevor Henrys, Stuart A Magens, Diana Niessen, Frank Hansaraj, Dhiresh Heat Flow and Hydrologic Characteristics at the AND-1B borehole, ANDRILL McMurdo Ice Shelf Project, Antarctica |
topic_facet |
Earth Sciences |
description |
The Antarctic Drilling Program (ANDRILL) successfully drilled and cored a borehole, AND-1B, beneath the McMurdo Ice Shelf and into a flexural moat basin that surrounds Ross Island. Total drilling depth reached 1285 m below sea floor (mbsf) with 98 percent core recovery for the detailed study of glacier dynamics. With the goal of obtaining complementary information regarding heat fl ow and permeability, which is vital to understanding the nature of marine hydrogeologic systems, a succession of three temperature logs was recorded over a five day span to monitor the gradual thermal recovery toward equilibrium conditions. These data were extrapolated to true, undisturbed temperatures, and they define a linear geothermal gradient of 76.7 K/km from the seafloor to 647 mbsf. Bulk thermal conductivities of the sedimentary rocks were derived from empirical mixing models and density measurements performed on core, and an average value of 1.5 W/mK ± 10 percent was determined. The corresponding estimate of heat fl ow at this site is 115 mW/m2. This value is relatively high but is consistent with other elevated heat-fl ow data associated with the Erebus Volcanic Province. Information regarding the origin and frequency of pathways for subsurface fluid flow is gleaned from drillers’ records, complementary geophysical logs, and core descriptions. Only two prominent permeable zones are identified and these correspond to two markedly different features within the rift basin; one is a distinct lithostratigraphic subunit consisting of a thin lava fl ow and the other is a heavily fractured interval within a single thick subunit. |
format |
Text |
author |
Morin, Roger H Williams, Trevor Henrys, Stuart A Magens, Diana Niessen, Frank Hansaraj, Dhiresh |
author_facet |
Morin, Roger H Williams, Trevor Henrys, Stuart A Magens, Diana Niessen, Frank Hansaraj, Dhiresh |
author_sort |
Morin, Roger H |
title |
Heat Flow and Hydrologic Characteristics at the AND-1B borehole, ANDRILL McMurdo Ice Shelf Project, Antarctica |
title_short |
Heat Flow and Hydrologic Characteristics at the AND-1B borehole, ANDRILL McMurdo Ice Shelf Project, Antarctica |
title_full |
Heat Flow and Hydrologic Characteristics at the AND-1B borehole, ANDRILL McMurdo Ice Shelf Project, Antarctica |
title_fullStr |
Heat Flow and Hydrologic Characteristics at the AND-1B borehole, ANDRILL McMurdo Ice Shelf Project, Antarctica |
title_full_unstemmed |
Heat Flow and Hydrologic Characteristics at the AND-1B borehole, ANDRILL McMurdo Ice Shelf Project, Antarctica |
title_sort |
heat flow and hydrologic characteristics at the and-1b borehole, andrill mcmurdo ice shelf project, antarctica |
publisher |
DigitalCommons@University of Nebraska - Lincoln |
publishDate |
2010 |
url |
https://digitalcommons.unl.edu/usgsstaffpub/347 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1356/viewcontent/Morin_GEOSPHERE_2010_Heat_Flow_and_hydrologic.pdf |
long_lat |
ENVELOPE(166.500,166.500,-78.000,-78.000) |
geographic |
Antarctic The Antarctic Ross Island McMurdo Ice Shelf |
geographic_facet |
Antarctic The Antarctic Ross Island McMurdo Ice Shelf |
genre |
Antarc* Antarctic Antarctica Ice Shelf McMurdo Ice Shelf Ross Island |
genre_facet |
Antarc* Antarctic Antarctica Ice Shelf McMurdo Ice Shelf Ross Island |
op_source |
USGS Staff -- Published Research |
op_relation |
https://digitalcommons.unl.edu/usgsstaffpub/347 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1356/viewcontent/Morin_GEOSPHERE_2010_Heat_Flow_and_hydrologic.pdf |
_version_ |
1782340362170269696 |