Figure 10. Porosity-depth curve for Site 897 (Scientific Party, 1994a), compared with that of Site 808 (Taira, Hill, Firth, et al., 1991), and with a typical mudstone section. (Hamilton, 1976). The mudstone porosities at Site 897 are less than for a typical section, presumably because the former are uncemented. Porosities at Site 897 are even less than those at Site 808, which have been reduced by deformation. The sample studied here (solid circle) has a porosity well below the mode at the same depth in Hole 897, but is similar to the shipboard value for the same core section. Deviation from an exponential porosity-depth relationship can probably be attributed to differences in lithologies and cementation above 500 mbsf, but the sharp downward general porosity increase below 600 mbsf must reflect high pore pressure.