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Mapping geothermal heat flux using permafrost thickness constrained by airborne electromagnetic surveys on the western coast of Ross Island, Antarctica

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Mapping geothermal heat flux using permafrost thickness constrained by airborne electromagnetic surveys on the western coast of Ross Island, Antarctica. / Foley, Neil; Tulaczyk, Slawomir; Auken, Esben; Grombacher, Denys; Mikucki, Jill; Foged, Nikolaj; Myers, Krista; Dugan, Hilary; Doran, Peter T.; Virginia, Ross A.

In: Exploration Geophysics, Vol. 51, No. 1, 01.2020, p. 84-93.

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Foley, Neil ; Tulaczyk, Slawomir ; Auken, Esben ; Grombacher, Denys ; Mikucki, Jill ; Foged, Nikolaj ; Myers, Krista ; Dugan, Hilary ; Doran, Peter T. ; Virginia, Ross A. / Mapping geothermal heat flux using permafrost thickness constrained by airborne electromagnetic surveys on the western coast of Ross Island, Antarctica. In: Exploration Geophysics. 2020 ; Vol. 51, No. 1. pp. 84-93.

Bibtex

@article{bf04d7c9c9dd4e6396df94581fec3613,
title = "Mapping geothermal heat flux using permafrost thickness constrained by airborne electromagnetic surveys on the western coast of Ross Island, Antarctica",
abstract = "Permafrost is ubiquitous at high latitudes, and its thickness is controlled by important local factors like geothermal flux, ground surface temperature and thermal properties of the subsurface. We use airborne transient electromagnetic resistivity measurements to determine permafrost thickness on the coast of Ross Island, Antarctica, which contains the active volcano Mt Erebus. Here, resistivity data clearly distinguish resistive permafrost from the electrically conductive fluid-saturated materials underlying it. For our study, we define permafrost as frozen material with a resistivity > 100 Ω·m; more conductive material contains a significant fraction of water or (more likely) brine. We observe that permafrost is very thin near the coast and thickens within several hundred metres inland to reach depths that are typically within the range of 300–400 m. We attribute the sharp near-shore increase in permafrost thickness to lateral heat conduction from the relatively warm ocean, possibly combined with seawater infiltration into the near-shore permafrost. We validate this result with a two-dimensional heat flow model and conclude that away from the thermal influence of the ocean, the local geothermal gradient and heat flux are about 45 ± 5 °C/km and 90 ± 13 mW/m2, respectively. These values are in line with published estimates in the vicinity of Mt Erebus and within the actively extending Terror Rift, but do not reflect a strong heat flow anomaly from volcanic activity of Mt Erebus. Measurements made previously in the McMurdo Dry Valleys, on the other side of McMurdo Sound, tend to be a few dozens of mW/m2 lower, likely reflecting its different tectonic setting on the uplifted rift shoulder of Transantarctic Mountains. Our study demonstrates a new approach towards constraining geothermal flux in polar regions using airborne electromagnetic (AEM) data that can be relatively efficiently collected on regional scales where ice coverage does not exceed the penetration limits of the AEM device, which for the device used is ∼ 500 m under the favourable conditions in the study area.",
keywords = "Antarctica, electrical resistivity, Geothermal flux, permafrost, MOUNT EREBUS, TIME-DOMAIN, MCMURDO, VOLCANO, SEA-ICE THICKNESS, THERMAL-CONDUCTIVITY, INVERSION, FLOW, ERUPTIVE HISTORY, CLIMATE",
author = "Neil Foley and Slawomir Tulaczyk and Esben Auken and Denys Grombacher and Jill Mikucki and Nikolaj Foged and Krista Myers and Hilary Dugan and Doran, {Peter T.} and Virginia, {Ross A.}",
year = "2020",
month = jan,
doi = "10.1080/08123985.2019.1651618",
language = "English",
volume = "51",
pages = "84--93",
journal = "Exploration Geophysics",
issn = "0812-3985",
publisher = "C S I R O Publishing",
number = "1",

}

RIS

TY - JOUR

T1 - Mapping geothermal heat flux using permafrost thickness constrained by airborne electromagnetic surveys on the western coast of Ross Island, Antarctica

AU - Foley, Neil

AU - Tulaczyk, Slawomir

AU - Auken, Esben

AU - Grombacher, Denys

AU - Mikucki, Jill

AU - Foged, Nikolaj

AU - Myers, Krista

AU - Dugan, Hilary

AU - Doran, Peter T.

AU - Virginia, Ross A.

PY - 2020/1

Y1 - 2020/1

N2 - Permafrost is ubiquitous at high latitudes, and its thickness is controlled by important local factors like geothermal flux, ground surface temperature and thermal properties of the subsurface. We use airborne transient electromagnetic resistivity measurements to determine permafrost thickness on the coast of Ross Island, Antarctica, which contains the active volcano Mt Erebus. Here, resistivity data clearly distinguish resistive permafrost from the electrically conductive fluid-saturated materials underlying it. For our study, we define permafrost as frozen material with a resistivity > 100 Ω·m; more conductive material contains a significant fraction of water or (more likely) brine. We observe that permafrost is very thin near the coast and thickens within several hundred metres inland to reach depths that are typically within the range of 300–400 m. We attribute the sharp near-shore increase in permafrost thickness to lateral heat conduction from the relatively warm ocean, possibly combined with seawater infiltration into the near-shore permafrost. We validate this result with a two-dimensional heat flow model and conclude that away from the thermal influence of the ocean, the local geothermal gradient and heat flux are about 45 ± 5 °C/km and 90 ± 13 mW/m2, respectively. These values are in line with published estimates in the vicinity of Mt Erebus and within the actively extending Terror Rift, but do not reflect a strong heat flow anomaly from volcanic activity of Mt Erebus. Measurements made previously in the McMurdo Dry Valleys, on the other side of McMurdo Sound, tend to be a few dozens of mW/m2 lower, likely reflecting its different tectonic setting on the uplifted rift shoulder of Transantarctic Mountains. Our study demonstrates a new approach towards constraining geothermal flux in polar regions using airborne electromagnetic (AEM) data that can be relatively efficiently collected on regional scales where ice coverage does not exceed the penetration limits of the AEM device, which for the device used is ∼ 500 m under the favourable conditions in the study area.

AB - Permafrost is ubiquitous at high latitudes, and its thickness is controlled by important local factors like geothermal flux, ground surface temperature and thermal properties of the subsurface. We use airborne transient electromagnetic resistivity measurements to determine permafrost thickness on the coast of Ross Island, Antarctica, which contains the active volcano Mt Erebus. Here, resistivity data clearly distinguish resistive permafrost from the electrically conductive fluid-saturated materials underlying it. For our study, we define permafrost as frozen material with a resistivity > 100 Ω·m; more conductive material contains a significant fraction of water or (more likely) brine. We observe that permafrost is very thin near the coast and thickens within several hundred metres inland to reach depths that are typically within the range of 300–400 m. We attribute the sharp near-shore increase in permafrost thickness to lateral heat conduction from the relatively warm ocean, possibly combined with seawater infiltration into the near-shore permafrost. We validate this result with a two-dimensional heat flow model and conclude that away from the thermal influence of the ocean, the local geothermal gradient and heat flux are about 45 ± 5 °C/km and 90 ± 13 mW/m2, respectively. These values are in line with published estimates in the vicinity of Mt Erebus and within the actively extending Terror Rift, but do not reflect a strong heat flow anomaly from volcanic activity of Mt Erebus. Measurements made previously in the McMurdo Dry Valleys, on the other side of McMurdo Sound, tend to be a few dozens of mW/m2 lower, likely reflecting its different tectonic setting on the uplifted rift shoulder of Transantarctic Mountains. Our study demonstrates a new approach towards constraining geothermal flux in polar regions using airborne electromagnetic (AEM) data that can be relatively efficiently collected on regional scales where ice coverage does not exceed the penetration limits of the AEM device, which for the device used is ∼ 500 m under the favourable conditions in the study area.

KW - Antarctica

KW - electrical resistivity

KW - Geothermal flux

KW - permafrost

KW - MOUNT EREBUS

KW - TIME-DOMAIN

KW - MCMURDO

KW - VOLCANO

KW - SEA-ICE THICKNESS

KW - THERMAL-CONDUCTIVITY

KW - INVERSION

KW - FLOW

KW - ERUPTIVE HISTORY

KW - CLIMATE

UR - http://www.scopus.com/inward/record.url?scp=85070954433&partnerID=8YFLogxK

U2 - 10.1080/08123985.2019.1651618

DO - 10.1080/08123985.2019.1651618

M3 - Journal article

AN - SCOPUS:85070954433

VL - 51

SP - 84

EP - 93

JO - Exploration Geophysics

JF - Exploration Geophysics

SN - 0812-3985

IS - 1

ER -