A Review of Arctic Gas Hydrates as a Source of Methane in Global Change
Atmospheric concentrations of methane are currently increasing at rates of about one percent per year, leading to a concern that methane, a greenhouse gas, will become an increasingly significant factor in global warming. One potential source of enormous volumes of methane is natural gas hydrates, w...
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ftdtic:ADP007358 2023-05-15T14:56:38+02:00 A Review of Arctic Gas Hydrates as a Source of Methane in Global Change Kvenvolden, Keith A. GEOLOGICAL SURVEY MENLO PARK CA 1992-03 text/html http://www.dtic.mil/docs/citations/ADP007358 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADP007358 en eng http://www.dtic.mil/docs/citations/ADP007358 APPROVED FOR PUBLIC RELEASE DTIC AND NTIS Geography Geology Geochemistry and Mineralogy Meteorology *ATMOSPHERICS *METHANE *ARCTIC REGIONS DEPTH GLOBAL HYDRATES MOLECULES NATURAL GAS OCEANS OFFSHORE PERMAFROST PRESSURE RATES REGIONS SEA LEVEL SEDIMENTS SOLIDS STABILITY SUBSURFACE SURFACES TEMPERATURE VOLUME WATER SYMPOSIA GREENHOUSE EFFECT Component Reports *Gas hydrates *Global change Warming Outer continental margin Continental shelf Relict Text 1992 ftdtic 2016-02-19T17:39:58Z Atmospheric concentrations of methane are currently increasing at rates of about one percent per year, leading to a concern that methane, a greenhouse gas, will become an increasingly significant factor in global warming. One potential source of enormous volumes of methane is natural gas hydrates, which are solids composed of cages of water molecules that contain gas molecules, mainly methane. Gas hydrates are stable only within certain ranges of temperature and pressure; outside these ranges, the cages break down and the gas molecules escape. The Arctic is particularly well endowed with gas hydrates because conditions for their occurrence are met in three distinct regions: (1) offshore in sediments of the outer continental margin, at water depths between about 400 and 2800 m, where the base of the zone of gas hydrate stability ranges from about 300 to 700 m below the sea floor; (2) onshore in areas of continuous permafrost, where the zone of gas hydrate stability ranges in subsurface depth from about 200 to 1200 m; and (3) on the nearshore continental shelf, where relict permafrost has persisted since times of lower sea level when the present shelf was exposed to cold subaerial temperatures. Because gas hydrates occur close to the earth's surface in these three regions, they are affected by surficial changes in pressure and temperature, and thus destabilized gas hydrates may be sources of atmospheric methane. This article is from 'Proceedings of the International Conference on the Role of Polar Regions in Global Change Held in Fairbanks, Alaska on 11-15 June 1990. Volume 2', AD-A253 028, p696-701. See also Volume 1, AD-A253 027. Text Arctic Global warming permafrost Alaska Defense Technical Information Center: DTIC Technical Reports database Arctic Fairbanks |
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Open Polar |
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Defense Technical Information Center: DTIC Technical Reports database |
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ftdtic |
language |
English |
topic |
Geography Geology Geochemistry and Mineralogy Meteorology *ATMOSPHERICS *METHANE *ARCTIC REGIONS DEPTH GLOBAL HYDRATES MOLECULES NATURAL GAS OCEANS OFFSHORE PERMAFROST PRESSURE RATES REGIONS SEA LEVEL SEDIMENTS SOLIDS STABILITY SUBSURFACE SURFACES TEMPERATURE VOLUME WATER SYMPOSIA GREENHOUSE EFFECT Component Reports *Gas hydrates *Global change Warming Outer continental margin Continental shelf Relict |
spellingShingle |
Geography Geology Geochemistry and Mineralogy Meteorology *ATMOSPHERICS *METHANE *ARCTIC REGIONS DEPTH GLOBAL HYDRATES MOLECULES NATURAL GAS OCEANS OFFSHORE PERMAFROST PRESSURE RATES REGIONS SEA LEVEL SEDIMENTS SOLIDS STABILITY SUBSURFACE SURFACES TEMPERATURE VOLUME WATER SYMPOSIA GREENHOUSE EFFECT Component Reports *Gas hydrates *Global change Warming Outer continental margin Continental shelf Relict Kvenvolden, Keith A. A Review of Arctic Gas Hydrates as a Source of Methane in Global Change |
topic_facet |
Geography Geology Geochemistry and Mineralogy Meteorology *ATMOSPHERICS *METHANE *ARCTIC REGIONS DEPTH GLOBAL HYDRATES MOLECULES NATURAL GAS OCEANS OFFSHORE PERMAFROST PRESSURE RATES REGIONS SEA LEVEL SEDIMENTS SOLIDS STABILITY SUBSURFACE SURFACES TEMPERATURE VOLUME WATER SYMPOSIA GREENHOUSE EFFECT Component Reports *Gas hydrates *Global change Warming Outer continental margin Continental shelf Relict |
description |
Atmospheric concentrations of methane are currently increasing at rates of about one percent per year, leading to a concern that methane, a greenhouse gas, will become an increasingly significant factor in global warming. One potential source of enormous volumes of methane is natural gas hydrates, which are solids composed of cages of water molecules that contain gas molecules, mainly methane. Gas hydrates are stable only within certain ranges of temperature and pressure; outside these ranges, the cages break down and the gas molecules escape. The Arctic is particularly well endowed with gas hydrates because conditions for their occurrence are met in three distinct regions: (1) offshore in sediments of the outer continental margin, at water depths between about 400 and 2800 m, where the base of the zone of gas hydrate stability ranges from about 300 to 700 m below the sea floor; (2) onshore in areas of continuous permafrost, where the zone of gas hydrate stability ranges in subsurface depth from about 200 to 1200 m; and (3) on the nearshore continental shelf, where relict permafrost has persisted since times of lower sea level when the present shelf was exposed to cold subaerial temperatures. Because gas hydrates occur close to the earth's surface in these three regions, they are affected by surficial changes in pressure and temperature, and thus destabilized gas hydrates may be sources of atmospheric methane. This article is from 'Proceedings of the International Conference on the Role of Polar Regions in Global Change Held in Fairbanks, Alaska on 11-15 June 1990. Volume 2', AD-A253 028, p696-701. See also Volume 1, AD-A253 027. |
author2 |
GEOLOGICAL SURVEY MENLO PARK CA |
format |
Text |
author |
Kvenvolden, Keith A. |
author_facet |
Kvenvolden, Keith A. |
author_sort |
Kvenvolden, Keith A. |
title |
A Review of Arctic Gas Hydrates as a Source of Methane in Global Change |
title_short |
A Review of Arctic Gas Hydrates as a Source of Methane in Global Change |
title_full |
A Review of Arctic Gas Hydrates as a Source of Methane in Global Change |
title_fullStr |
A Review of Arctic Gas Hydrates as a Source of Methane in Global Change |
title_full_unstemmed |
A Review of Arctic Gas Hydrates as a Source of Methane in Global Change |
title_sort |
review of arctic gas hydrates as a source of methane in global change |
publishDate |
1992 |
url |
http://www.dtic.mil/docs/citations/ADP007358 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADP007358 |
geographic |
Arctic Fairbanks |
geographic_facet |
Arctic Fairbanks |
genre |
Arctic Global warming permafrost Alaska |
genre_facet |
Arctic Global warming permafrost Alaska |
op_source |
DTIC AND NTIS |
op_relation |
http://www.dtic.mil/docs/citations/ADP007358 |
op_rights |
APPROVED FOR PUBLIC RELEASE |
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1766328725294546944 |