4. CONSOLIDATION AND PERMEABILITY CHARACTERISTICS OF SEDIMENTS FROM DEEP

The consolidation-permeability characteristics and index properties of seven sediment samples from Deep Sea Drill-ing Project Leg 93, Sites 603 and 604, were studied in an effort to gain an understanding of the processes acting on con-tourite sediments. Three hemipelagic silty clay contourite sediment samples collected with the hydraulic piston corer (HPC) from depths between 47 and 83 m were found to be overconsolidated. X-radiographs indicated these samples to be relatively undisturbed. Coring and degassing disturbance has produced an apparent state of underconsolidation for one near-surface and two deeper samples from Site 603. Permeability values ranged between 2.7 × 10~7 and 6.4 × I 0 " 8 cm/s. The one sample tested from Site 604 at a depth of 4.42 m was found to be overconsolidated. The permeabil-ity value for this sample, 1.4 × 10~4 cm/s, was considerably higher than those measured at Site 603. The presence of near-surface Pleistocene sediment with virtually no Holocene sediment cover at both sites suggests sporadic winnowing by fluctuating currents and/or erosion of modern sediment overburden, resulting in overconsolidated sediments