Submarine gas seepage in a mixed contractional and shear deformation regime: Cases from the Hikurangi oblique-subduction margin.

Plaza-Faverola, Andreia, Pecher, Ingo, Crutchley, Gareth , Barnes, Philip M., Bünz, Stefan, Golding, Thomas, Klaeschen, Dirk , Papenberg, Cord and Bialas, Jörg (2014) Submarine gas seepage in a mixed contractional and shear deformation regime: Cases from the Hikurangi oblique-subduction margin. Open Access Geochemistry, Geophysics, Geosystems, 15 (2). pp. 416-433. DOI 10.1002/2013GC005082.

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Abstract

Gas seepage from marine sediments has implications for understanding feedbacks between the global carbon reservoir, seabed ecology and climate change. Although the relationship between hydrates, gas chimneys and seafloor seepage is well established, the nature of fluid sources and plumbing mechanisms controlling fluid escape into the hydrate zone and up to the seafloor remain one of the least understood components of fluid migration systems. In this study we present the analysis of new three-dimensional high-resolution seismic data acquired to investigate fluid migration systems sustaining active seafloor seepage at Omakere Ridge, on the Hikurangi subduction margin, New Zealand. The analysis reveals at high resolution, complex overprinting fault structures (i.e. protothrusts, normal faults from flexural extension, and shallow (<1 km) arrays of oblique shear structures) implicated in fluid migration within the gas hydrate stability zone in an area of 2x7 km. In addition to fluid migration systems sustaining seafloor seepage on both sides of a central thrust fault, the data show seismic evidence for sub-seafloor gas-rich fluid accumulation associated with proto-thrusts and extensional faults. In these latter systems fluid pressure dissipation through time has been favored, hindering the development of gas chimneys. We discuss the elements of the distinct fluid migration systems and the influence that a complex partitioning of stress may have on the evolution of fluid flow systems in active subduction margins.

Document Type: Article
Additional Information: WOS:000335905600008
Keywords: 3D-seismic; seepage; fluid migration; gas hydrates; shear faults; subduction; Hikurangi
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Refereed: Yes
Open Access Journal?: No
Publisher: AGU (American Geophysical Union), Wiley
Projects: Future Ocean
Expeditions/Models/Experiments:
Date Deposited: 07 Jan 2014 10:59
Last Modified: 27 Feb 2018 14:31
URI: https://oceanrep.geomar.de/id/eprint/22900

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