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International Conference on Gas Hydrates (ICGH) (6th : 2008)

EROSION OF SEAFLOOR RIDGES AT THE TOP OF THE GAS HYDRATE STABILITY ZONE, HIKURANGI MARGIN, NEW ZEALAND – NEW INSIGHTS FROM RESEARCH CRUISES BETWEEN 2005 AND 2007. Pecher, Ingo A.; Henrys, Stuart A.; Ellis, Susan; Crutchley, Gareth; Fohrmann, Miko; Gorman, Andrew R.; Greinert, Jens; Chiswell, Stephen M.; TAN0607 Scientific Party; SO191 Scientific Party

Abstract

It was proposed that erosion of subsea ridges on the Hikurangi margin may be linked to a fluctuating level of the top of gas hydrate stability in the ocean. Since publication of this hypothesis, three field campaigns were conducted in the study area. Here we summarize relevant results from these cruises. We found that water temperature fluctuations occur at lower frequencies and higher amplitudes than previously thought, making it more likely that temperature changes reach sub-seafloor gas hydrates. Dredge samples encountered numerous consolidated mudstones. We speculate that gas hydrate “freeze-thaw” cycles may lead to dilation of fractures in mudstones due to capillary forces, weakening the seafloor. Ubiquitous gas pockets beneath the ridge may lead to overpressure that may also contribute to seafloor fracturing.

Item Metadata

Title
EROSION OF SEAFLOOR RIDGES AT THE TOP OF THE GAS HYDRATE STABILITY ZONE, HIKURANGI MARGIN, NEW ZEALAND – NEW INSIGHTS FROM RESEARCH CRUISES BETWEEN 2005 AND 2007.
Creator
Pecher, Ingo A.; Henrys, Stuart A.; Ellis, Susan; Crutchley, Gareth; Fohrmann, Miko; Gorman, Andrew R.; Greinert, Jens; Chiswell, Stephen M.; TAN0607 Scientific Party; SO191 Scientific Party
Contributor
University of British Columbia. Department of Chemical and Biological Engineering; International Conference on Gas Hydrates (6th : 2008 : Vancouver, B.C.)
Date Issued
2008-07
Description
It was proposed that erosion of subsea ridges on the Hikurangi margin may be linked to a fluctuating level of the top of gas hydrate stability in the ocean. Since publication of this hypothesis, three field campaigns were conducted in the study area. Here we summarize relevant results from these cruises. We found that water temperature fluctuations occur at lower frequencies and higher amplitudes than previously thought, making it more likely that temperature changes reach sub-seafloor gas hydrates. Dredge samples encountered numerous consolidated mudstones. We speculate that gas hydrate “freeze-thaw” cycles may lead to dilation of fractures in mudstones due to capillary forces, weakening the seafloor. Ubiquitous gas pockets beneath the ridge may lead to overpressure that may also contribute to seafloor fracturing.
Extent
451778 bytes
Subject
Gas hydrates; Seafloor stability; Hikurangi Margin
Geographic Location
Hikurangi (N.Z.)
Genre
Conference Paper
Type
Text
File Format
application/pdf
Language
eng
Date Available
2016-11-21
Provider
Vancouver : University of British Columbia Library
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International
DOI
10.14288/1.0041097
URI
http://hdl.handle.net/2429/1551
Affiliation
Non UBC
Citation
Pecher, Ingo A.; Henrys, Stuart A.; Ellis, Susan; Crutchley, Gareth; Fohrmann, Miko, Gorman, Andrew R.; Greinert, Jens; Chiswell, Stephen M. 2008. EROSION OF SEAFLOOR RIDGES AT THE TOP OF THE GAS HYDRATE STABILITY ZONE, HIKURANGI MARGIN, NEW ZEALAND – NEW INSIGHTS FROM RESEARCH CRUISES BETWEEN 2005 AND 2007. Proceedings of the 6th International Conference on Gas Hydrates (ICGH 2008), Vancouver, British Columbia, CANADA, July 6-10, 2008.
Peer Review Status
Unreviewed
Copyright Holder
Pecher, Ingo A.
Rights URI
http://creativecommons.org/licenses/by-nc-nd/4.0/
Aggregated Source Repository
DSpace

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Attribution-NonCommercial-NoDerivatives 4.0 International