Submarine Seepage of Natural Gas in Norton Sound, Alaska
Unusual concentrations of dissolved two- to four-carbon alkanes were observed in the waters in Norton Sound in a localized area approximately 40 kilometers south of Nome, Alaska, in 1976. The hydrocarbons were identified in the near-bottom waters downcurrent for more than 100 kilometers from a sea-f...
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American Association for the Advancement of Science (AAAS)
1977
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Online Access: | http://dx.doi.org/10.1126/science.198.4322.1149 https://www.science.org/doi/pdf/10.1126/science.198.4322.1149 |
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craaas:10.1126/science.198.4322.1149 2024-06-09T07:47:54+00:00 Submarine Seepage of Natural Gas in Norton Sound, Alaska Cline, Joel D. Holmes, Mark L. 1977 http://dx.doi.org/10.1126/science.198.4322.1149 https://www.science.org/doi/pdf/10.1126/science.198.4322.1149 en eng American Association for the Advancement of Science (AAAS) Science volume 198, issue 4322, page 1149-1153 ISSN 0036-8075 1095-9203 journal-article 1977 craaas https://doi.org/10.1126/science.198.4322.1149 2024-05-16T12:55:30Z Unusual concentrations of dissolved two- to four-carbon alkanes were observed in the waters in Norton Sound in a localized area approximately 40 kilometers south of Nome, Alaska, in 1976. The hydrocarbons were identified in the near-bottom waters downcurrent for more than 100 kilometers from a sea-floor point source. Preliminary dynamic modeling estimates of the initial gas phase composition predict methane/ethane and ethane/propane ratios of 24 and 1.7, respectively, assuming the hydrocarbons were introduced by bubbles. The low ethane/propane ratio is indicative of gas from a liquid petroleum source rather than from nonassociated or biogenic natural gas. Preliminary data on the structural geology of Norton Basin lend support to the interpretation based on the hydrocarbon plume. Unconformably truncated strata dip basinward from the seep locus; acoustic anomalies and numerous steeply dipping faults in the immediate vicinity of the seep are corroborating evidence that shallow gas- or petroleum-charged sediments and strata coincide with avenues for migration of mobile hydrocarbons to the sea floor. These factors, taken in concert with the sedimentological regime, the recent revision (increase) of basin depth estimates, and the highly localized hydrocarbon source, strongly suggest a thermogenic rather than a recent biogenic origin for these gaseous compounds. Article in Journal/Newspaper Nome Alaska AAAS Resource Center (American Association for the Advancement of Science) Norton Sound ENVELOPE(69.507,69.507,-49.202,-49.202) Science 198 4322 1149 1153 |
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Open Polar |
collection |
AAAS Resource Center (American Association for the Advancement of Science) |
op_collection_id |
craaas |
language |
English |
description |
Unusual concentrations of dissolved two- to four-carbon alkanes were observed in the waters in Norton Sound in a localized area approximately 40 kilometers south of Nome, Alaska, in 1976. The hydrocarbons were identified in the near-bottom waters downcurrent for more than 100 kilometers from a sea-floor point source. Preliminary dynamic modeling estimates of the initial gas phase composition predict methane/ethane and ethane/propane ratios of 24 and 1.7, respectively, assuming the hydrocarbons were introduced by bubbles. The low ethane/propane ratio is indicative of gas from a liquid petroleum source rather than from nonassociated or biogenic natural gas. Preliminary data on the structural geology of Norton Basin lend support to the interpretation based on the hydrocarbon plume. Unconformably truncated strata dip basinward from the seep locus; acoustic anomalies and numerous steeply dipping faults in the immediate vicinity of the seep are corroborating evidence that shallow gas- or petroleum-charged sediments and strata coincide with avenues for migration of mobile hydrocarbons to the sea floor. These factors, taken in concert with the sedimentological regime, the recent revision (increase) of basin depth estimates, and the highly localized hydrocarbon source, strongly suggest a thermogenic rather than a recent biogenic origin for these gaseous compounds. |
format |
Article in Journal/Newspaper |
author |
Cline, Joel D. Holmes, Mark L. |
spellingShingle |
Cline, Joel D. Holmes, Mark L. Submarine Seepage of Natural Gas in Norton Sound, Alaska |
author_facet |
Cline, Joel D. Holmes, Mark L. |
author_sort |
Cline, Joel D. |
title |
Submarine Seepage of Natural Gas in Norton Sound, Alaska |
title_short |
Submarine Seepage of Natural Gas in Norton Sound, Alaska |
title_full |
Submarine Seepage of Natural Gas in Norton Sound, Alaska |
title_fullStr |
Submarine Seepage of Natural Gas in Norton Sound, Alaska |
title_full_unstemmed |
Submarine Seepage of Natural Gas in Norton Sound, Alaska |
title_sort |
submarine seepage of natural gas in norton sound, alaska |
publisher |
American Association for the Advancement of Science (AAAS) |
publishDate |
1977 |
url |
http://dx.doi.org/10.1126/science.198.4322.1149 https://www.science.org/doi/pdf/10.1126/science.198.4322.1149 |
long_lat |
ENVELOPE(69.507,69.507,-49.202,-49.202) |
geographic |
Norton Sound |
geographic_facet |
Norton Sound |
genre |
Nome Alaska |
genre_facet |
Nome Alaska |
op_source |
Science volume 198, issue 4322, page 1149-1153 ISSN 0036-8075 1095-9203 |
op_doi |
https://doi.org/10.1126/science.198.4322.1149 |
container_title |
Science |
container_volume |
198 |
container_issue |
4322 |
container_start_page |
1149 |
op_container_end_page |
1153 |
_version_ |
1801379369820618752 |