TY - JOUR
T1 - The potential influence of shallow gas and gas hydrates on sea floor erosion of Rock Garden, an uplifted ridge offshore of New Zealand
AU - Crutchley, Gareth J.
AU - Geiger, Sebastian
AU - Pecher, Ingo A.
AU - Gorman, Andrew R.
AU - Zhu, Hai
AU - Henrys, Stuart A.
PY - 2010
Y1 - 2010
N2 - Regional erosion of the Rock Garden ridge top, a bathymetric high within New Zealand's Hikurangi Subduction Margin, is likely associated with its gas hydrate system. Seismic data reveal gas pockets that appear partially trapped beneath the shallow base of gas hydrate stability. Steady-state fluid flow simulations, conducted on detailed two-dimensional geological models, reveal that anomalous fluid pressure can develop close to the sea floor in response to lower-permeability hydrate-bearing sediments and underlying gas pockets. Transient simulations indicate that large-scale cycling of fluid overpressure may occur on time scales of a few to tens of years. We predict intense regions of hydro-fracturing to preferentially develop beneath the ridge top rather than beneath the flanks, due to more pronounced overpressure generation and gas migration through hydrate-bearing sediments. Results suggest that sediment weakening and erosion of the ridge top by hydro-fracturing could be owed to fluid dynamics of the shallow gas hydrate system.
AB - Regional erosion of the Rock Garden ridge top, a bathymetric high within New Zealand's Hikurangi Subduction Margin, is likely associated with its gas hydrate system. Seismic data reveal gas pockets that appear partially trapped beneath the shallow base of gas hydrate stability. Steady-state fluid flow simulations, conducted on detailed two-dimensional geological models, reveal that anomalous fluid pressure can develop close to the sea floor in response to lower-permeability hydrate-bearing sediments and underlying gas pockets. Transient simulations indicate that large-scale cycling of fluid overpressure may occur on time scales of a few to tens of years. We predict intense regions of hydro-fracturing to preferentially develop beneath the ridge top rather than beneath the flanks, due to more pronounced overpressure generation and gas migration through hydrate-bearing sediments. Results suggest that sediment weakening and erosion of the ridge top by hydro-fracturing could be owed to fluid dynamics of the shallow gas hydrate system.
UR - http://www.scopus.com/inward/record.url?scp=77952959418&partnerID=8YFLogxK
U2 - 10.1007/s00367-010-0186-y
DO - 10.1007/s00367-010-0186-y
M3 - Article
AN - SCOPUS:77952959418
SN - 0276-0460
VL - 30
SP - 283
EP - 303
JO - Geo-Marine Letters
JF - Geo-Marine Letters
IS - 3-4
ER -