FY 1984

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

Abbott, D.W., W. Menke, M. Hobart, R.N. Anderson, and R.W. Embley

Geophys. Res. Lett., 11(5), doi: 10.1029/GL011i005p00485, 485–488 (1984)

Measurements of temperature gradients and excess pore pressure in the surficial sediment of a fault block basin in the Guatemala Basin correlates 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 to 10 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 seafloor spreading models, the oceanic basin may be the site of a vigorous hydrothermal circulation system. The pore water advection in the sediments may be driven by this larger scale circulation.