| Michelle Ellis, Rob. Evans, Deborah Hutchinson, Pat Hart, Joan Gardner, Rick Hagen.
,
Electromagnetic Surveying of Seafloor Mounds in the Northern Gulf of Mexico
, Marine and Petroleum Geology, 2008
Seafloor controlled source electromagnetic data, probing the
uppermost 30m of seafloor sediments, have been collected with a towed magnetic
dipole-dipole system across two seafloor mounds at approximately 1300 m water
depth in the northern Gulf of Mexico. One of
these mounds was the focus of a recent gas hydrate research drilling program.
Rather than the highly resistive response expected of massive gas hydrate
within the confines of the mounds, the EM data are dominated by the effects of
raised temperatures and pore fluid salinities that result in an electrically
conductive seafloor. This structure suggests fluid advection towards the
seafloor is taking place beneath both mounds. Similar responses are seen at
discrete locations away from the mounds in areas that might be associated with
faults, further suggesting substantial shallow fluid circulation. Raised
temperatures and salinities may inhibit gas hydrate formation at depth as has
been suggested at other similar locations in the Gulf of
Mexico.
Reference: Ellis et al., Marine and Petroleum Geology, 25, 960-968, 2008
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