Geophysical and geochemical survey of a large marine pockmark on the Malin Shelf, Ireland

Abstract:

Marine pockmarks are a specific type of seabed geological setting resembling craters or pits and are considered seabed surface expressions of fluid flow in the subsurface. A large composite pockmark on the Malin Shelf, off the northern coast of Ireland was surveyed and ground truthed to assess its activity and investigate fluid related processes in the subsurface. Geophysical (including acoustic and electromagnetic) data confirmed the subsurface presence of signatures typical of fluids within the sediment. Shallow seismic profiling revealed a large shallow gas pocket and typical gas related indicators such as acoustic blanking and enhanced reflectors present underneath and around the large pockmark. Sulphate profiles indicate that gas from the shallow reservoir has been migrating upwards, at least recently. However, there are no chimney structures observed in the sub‐bottom data and the migration pathways …

Año de publicación:

2012

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Fuente:

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