Dallas Abbott, William Menke, Michael Hobart, Roger N. Anderson and Robert W. Embley

Correlated sediment thickness, temperature gradient and excess pore pressure in a marine fault block basin

Geophysical Research Letters(May 1984), 11(5):485-488

Index Terms/Descriptors: advection; block structures; crust; East Pacific; faults; geochemistry; geophysical surveys; geothermal gradient; Guatemala Basin; heat flow; marine sediments; North American Pacific; North Pacific; Northeast Pacific; ocean floors; oceanic crust; Pacific Ocean; permeability; physical properties; pore pressure; pore water; pressure; sediments; surveys; thermal conductivity; thickness

Latitude & LongitudeN9°45'00'' - N10°15'00'' and W91°00'00'' - W90°00'00''


Measurements of temperature gradient and excess pore pressure in the surficial sediment of a fault block basin in the Guatemala Basin correlate with sediment thickness. The temperature gradient is smaller and the excess pore pressure gradient is more negative in areas of thinner sediment. This correlation is explained by postulating downward pore water advection within the sediments with flow velocities on the order of 10 (super -9) to 10 (super -8) m/s in the thinnest sediments and much less flow in the thickest sediments. Sediment physical properties and pore water chemistry also support this interpretation. Since the conductive heat flow of the basin as a whole is less than one third that predicted by sea-floor spreading models, the oceanic basement may be the site of a vigorous hydrothermal circulation system. Pore-water advection in the sediments may be driven by this larger scale circulation.--Modified journal abstract.