Porewater Geochemical Assessment of Seismic Indications for Gas Hydrate Presence and Absence: Mahia Slope, East of New Zealand’s North Island
We compare sediment vertical methane flux off the Mahia Peninsula, on the Hikurangi Margin, east of New Zealand’s North Island, with a combination of geochemical, multichannel seismic and sub-bottom profiler data. Stable carbon isotope data provided an overview of methane contributions to shallow se...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-02-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/15/3/1233 |
| _version_ | 1827660663800987648 |
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| author | Richard B. Coffin Gareth Crutchley Ingo Pecher Brandon Yoza Thomas J. Boyd Joshu Mountjoy |
| author_facet | Richard B. Coffin Gareth Crutchley Ingo Pecher Brandon Yoza Thomas J. Boyd Joshu Mountjoy |
| author_sort | Richard B. Coffin |
| collection | DOAJ |
| description | We compare sediment vertical methane flux off the Mahia Peninsula, on the Hikurangi Margin, east of New Zealand’s North Island, with a combination of geochemical, multichannel seismic and sub-bottom profiler data. Stable carbon isotope data provided an overview of methane contributions to shallow sediment carbon pools. Methane varied considerably in concentration and vertical flux across stations in close proximities. At two Mahia transects, methane profiles correlated well with integrated seismic and TOPAS data for predicting vertical methane migration rates from deep to shallow sediment. However, at our “control site”, where no seismic blanking or indications of vertical gas migration were observed, geochemical data were similar to the two Mahia transect lines. This apparent mismatch between seismic and geochemistry data suggests a potential to underestimate gas hydrate volumes based on standard seismic data interpretations. To accurately assess global gas hydrate deposits, multiple approaches for initial assessment, e.g., seismic data interpretation, heatflow profiling and controlled-source electromagnetics, should be compared to geochemical sediment and porewater profiles. A more thorough data matrix will provide better accuracy in gas hydrate volume for modeling climate change and potential available energy content. |
| first_indexed | 2024-03-09T23:54:48Z |
| format | Article |
| id | doaj.art-abb7a024297c4fc1a16d3ad08486c17b |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-09T23:54:48Z |
| publishDate | 2022-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-abb7a024297c4fc1a16d3ad08486c17b2023-11-23T16:27:29ZengMDPI AGEnergies1996-10732022-02-01153123310.3390/en15031233Porewater Geochemical Assessment of Seismic Indications for Gas Hydrate Presence and Absence: Mahia Slope, East of New Zealand’s North IslandRichard B. Coffin0Gareth Crutchley1Ingo Pecher2Brandon Yoza3Thomas J. Boyd4Joshu Mountjoy5Department of Physical and Environmental Science, Texas A&M University—Corpus Christi, Corpus Christi, TX 78412, USAGEOMAR Helmholtz Centre for Ocean Research Kiel, 24103 Kiel, GermanyDepartment of Physical and Environmental Science, Texas A&M University—Corpus Christi, Corpus Christi, TX 78412, USAHawai’i Natural Energy Institute, University of Hawai‘i at Mānoa, Honolulu, HI 96822, USAUS Naval Research Laboratory, Code 6181, 4555 Overlook Ave., SW, Washington, DC 20001, USANational Institute of Water and Atmosphere, Wellington 5012, New ZealandWe compare sediment vertical methane flux off the Mahia Peninsula, on the Hikurangi Margin, east of New Zealand’s North Island, with a combination of geochemical, multichannel seismic and sub-bottom profiler data. Stable carbon isotope data provided an overview of methane contributions to shallow sediment carbon pools. Methane varied considerably in concentration and vertical flux across stations in close proximities. At two Mahia transects, methane profiles correlated well with integrated seismic and TOPAS data for predicting vertical methane migration rates from deep to shallow sediment. However, at our “control site”, where no seismic blanking or indications of vertical gas migration were observed, geochemical data were similar to the two Mahia transect lines. This apparent mismatch between seismic and geochemistry data suggests a potential to underestimate gas hydrate volumes based on standard seismic data interpretations. To accurately assess global gas hydrate deposits, multiple approaches for initial assessment, e.g., seismic data interpretation, heatflow profiling and controlled-source electromagnetics, should be compared to geochemical sediment and porewater profiles. A more thorough data matrix will provide better accuracy in gas hydrate volume for modeling climate change and potential available energy content.https://www.mdpi.com/1996-1073/15/3/1233seismic datasub-bottom profiler datamethanevertical migrationcarbon isotope analysis |
| spellingShingle | Richard B. Coffin Gareth Crutchley Ingo Pecher Brandon Yoza Thomas J. Boyd Joshu Mountjoy Porewater Geochemical Assessment of Seismic Indications for Gas Hydrate Presence and Absence: Mahia Slope, East of New Zealand’s North Island Energies seismic data sub-bottom profiler data methane vertical migration carbon isotope analysis |
| title | Porewater Geochemical Assessment of Seismic Indications for Gas Hydrate Presence and Absence: Mahia Slope, East of New Zealand’s North Island |
| title_full | Porewater Geochemical Assessment of Seismic Indications for Gas Hydrate Presence and Absence: Mahia Slope, East of New Zealand’s North Island |
| title_fullStr | Porewater Geochemical Assessment of Seismic Indications for Gas Hydrate Presence and Absence: Mahia Slope, East of New Zealand’s North Island |
| title_full_unstemmed | Porewater Geochemical Assessment of Seismic Indications for Gas Hydrate Presence and Absence: Mahia Slope, East of New Zealand’s North Island |
| title_short | Porewater Geochemical Assessment of Seismic Indications for Gas Hydrate Presence and Absence: Mahia Slope, East of New Zealand’s North Island |
| title_sort | porewater geochemical assessment of seismic indications for gas hydrate presence and absence mahia slope east of new zealand s north island |
| topic | seismic data sub-bottom profiler data methane vertical migration carbon isotope analysis |
| url | https://www.mdpi.com/1996-1073/15/3/1233 |
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