Focussed fluid flow on the Hikurangi Margin, New Zealand - Evidence from possible local upwarping of the base of gas hydrate stability

Ingo A. Pecher, Stuart A. Henrys, Warren T. Wood, Nina Kukowski, Gareth J. Crutchley, Miko Fohrmann, Jeremy Kilner, Kim Senger, Andrew R. Gorman, Richard B. Coffin, Jens Greinert, Kevin Faure

    Research output: Contribution to journalArticle

    Abstract

    The southern Hikurangi Subduction Margin is characterized by significant accretion with predicted high rates of fluid expulsion. Bottom simulating reflections (BSRs) are widespread on this margin, predominantly occurring beneath thrust ridges. We present seismic data across the Porangahau Ridge on the outer accretionary wedge. The data show high-amplitude reflections above the regional BSR level. Based on polarity and reflection strength, we interpret these reflections as being caused by free gas. We propose that the presence of gas above the regional level of BSRs indicates local upwarping of the base of gas hydrate stability caused by advective heatflow from upward migrating fluids, although we cannot entirely rule out alternative processes. Simplified modelling of the increase of the thermal gradient associated with fluid flow suggests that funnelling of upward migrating fluids beneath low-permeability slope basins into the Porangahau Ridge would not lead to the pronounced thermal anomaly inferred from upwarping of the base of gas hydrate stability. Focussing of fluid flow is predicted to take place deep in the accretionary wedge and/or the underthrust sediments. Above the high-amplitude reflections, sediment reflectivity is low. A lack of lateral continuity of reflections suggests that reflectivity is lost because of a destruction of sediment layering from deformation rather than gas-hydrate-related amplitude blanking. Structural permeability from fracturing of sediments during deformation may facilitate fluid expulsion on the ridge. A gap in the BSR in the southern part of the study area may be caused by a loss of gas during fluid expulsion. We speculate that gaps in otherwise continuous BSRs that are observed beneath some thrusts on the Hikurangi Margin may be characteristic of other locations experiencing focussed fluid expulsion. © 2009 Elsevier B.V.

    Original languageEnglish
    Pages (from-to)99-113
    Number of pages15
    JournalMarine Geology
    Volume272
    Issue number1-4
    DOIs
    Publication statusPublished - 15 Jul 2010

    Fingerprint

    fluid expulsion
    gas hydrate
    fluid flow
    accretionary prism
    reflectivity
    sediment
    thrust
    gas
    permeability
    fluid
    temperature anomaly
    seismic data
    subduction
    accretion
    basin
    modeling

    Keywords

    • Fluid flow
    • Gas hydrates
    • Hikurangi Margin
    • Subduction zones

    Cite this

    Pecher, I. A., Henrys, S. A., Wood, W. T., Kukowski, N., Crutchley, G. J., Fohrmann, M., ... Faure, K. (2010). Focussed fluid flow on the Hikurangi Margin, New Zealand - Evidence from possible local upwarping of the base of gas hydrate stability. Marine Geology, 272(1-4), 99-113. https://doi.org/10.1016/j.margeo.2009.10.006
    Pecher, Ingo A. ; Henrys, Stuart A. ; Wood, Warren T. ; Kukowski, Nina ; Crutchley, Gareth J. ; Fohrmann, Miko ; Kilner, Jeremy ; Senger, Kim ; Gorman, Andrew R. ; Coffin, Richard B. ; Greinert, Jens ; Faure, Kevin. / Focussed fluid flow on the Hikurangi Margin, New Zealand - Evidence from possible local upwarping of the base of gas hydrate stability. In: Marine Geology. 2010 ; Vol. 272, No. 1-4. pp. 99-113.
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    Pecher, IA, Henrys, SA, Wood, WT, Kukowski, N, Crutchley, GJ, Fohrmann, M, Kilner, J, Senger, K, Gorman, AR, Coffin, RB, Greinert, J & Faure, K 2010, 'Focussed fluid flow on the Hikurangi Margin, New Zealand - Evidence from possible local upwarping of the base of gas hydrate stability', Marine Geology, vol. 272, no. 1-4, pp. 99-113. https://doi.org/10.1016/j.margeo.2009.10.006

    Focussed fluid flow on the Hikurangi Margin, New Zealand - Evidence from possible local upwarping of the base of gas hydrate stability. / Pecher, Ingo A.; Henrys, Stuart A.; Wood, Warren T.; Kukowski, Nina; Crutchley, Gareth J.; Fohrmann, Miko; Kilner, Jeremy; Senger, Kim; Gorman, Andrew R.; Coffin, Richard B.; Greinert, Jens; Faure, Kevin.

    In: Marine Geology, Vol. 272, No. 1-4, 15.07.2010, p. 99-113.

    Research output: Contribution to journalArticle

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    AU - Henrys, Stuart A.

    AU - Wood, Warren T.

    AU - Kukowski, Nina

    AU - Crutchley, Gareth J.

    AU - Fohrmann, Miko

    AU - Kilner, Jeremy

    AU - Senger, Kim

    AU - Gorman, Andrew R.

    AU - Coffin, Richard B.

    AU - Greinert, Jens

    AU - Faure, Kevin

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