HR: 0800h
AN: S51B-0148    [Abstracts]
TI: Permeability Measurements of Ocean Drilling Program Samples Collected From the Costa Rican Subduction Zone
AU: * Hays, T D
EM: troyhays@ufl.edu
AF: University of Florida, Department of Geology P.O.Box 112120, Gainesville, FL 32611 United States
AU: Screaton, E J
EM: screaton@geology.ufl.edu
AF: University of Florida, Department of Geology P.O.Box 112120, Gainesville, FL 32611 United States
AU: Gamage, K
EM: kusali@ufl.edu
AF: University of Florida, Department of Geology P.O.Box 112120, Gainesville, FL 32611 United States
AU: Martin, J
EM: jmmartin@ufl.edu
AF: University of Florida, Department of Geology P.O.Box 112120, Gainesville, FL 32611 United States
AB: Permeability is a key component in evaluating pore pressures and consolidation history in sediments. Core samples collected from the Costa Rican subduction zone were tested to determine their vertical permeabilities. The samples are from Ocean Drilling Program (ODP) Leg 205 Sites 1253, 1254, and 1255 and ODP Leg 170 Site 1040. The Costa Rican subduction zone has been shown to currently be a nonaccreting margin, and all samples are from within the underthrust sediments. The measurements were made using a constant head test by inducing a pressure gradient across the sample. Measurements were taken for three different consolidation pressures with five different pressure gradients induced across the sample in each consolidation. Two types of samples were tested; light colored, fine grained pelagic carbonates and dark colored, fine grained hemipelagic clays. Our results show two groupings of permeabilities, with the pelagic carbonates approximately two orders of magnitude higher than the hemipelagic clays. These results are consistent with permeabilities found by previous researchers.
DE: 5114 Permeability and porosity
DE: 3022 Marine sediments--processes and transport
DE: 3099 General or miscellaneous
SC: Seismology [S]
MN: 2004 AGU Fall Meeting