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doi:10.2204/iodp.proc.314315316.211.2011

Results

Table T1 summarizes the effective stress and estimated porosity and permeability at each consolidation step. In general, permeabilities decreased with increasing effective stress. Permeability is plotted as a function of porosity in Figure F3. Tests were attempted on five additional whole-round samples (315-C0001E-10H-3, 0.0–20.0 cm; 315-C0001F-11H-7, 101.0–116.0 cm; 315-C0001H-23R-3, 0.0–20.0 cm; 316-C0006F-10R-1, 16.5–27.5 cm; and 316-C0004C-6H-7, 0.0–15.0 cm) but were unsuccessful because of poor sample condition or irregular geometry. The measured permeabilities vary from ~2.51 × 10^–19 m² to ~5.26 × 10^–16 m². In general, the lower permeabilities tend to represent clay-rich sediments, whereas the higher permeabilities represent sand-rich, interbedded ash sediments or fractured samples.

Table T2 summarizes the details of ESEM fabric analysis results. Some of the samples used for permeability did not have adjacent samples for ESEM, and some ESEM samples displayed do not have permeability results, generally because of sample condition. Rose diagrams in Figure F4 show the orientations of the fabrics. The cumulative curves are shown in Figure F5. The average index of microfabric orientation is ~0.30–0.34. Most vertical sections show greater indexes of orientation and steeper cumulative slopes than the horizontal sections for samples from the slope layer at Sites C0001, C0004, and C0008 (Table T2; Fig. F5). Some samples from the accreted wedge at Site C0001, slope sediments in the footwall of the megasplay fault at Site C0004, and frontal thrust Sites C0006 and C0007 exhibit higher orientation indexes (0.37–0.54) and concomitant steeper cumulative slopes than other specimens (Table T2; Fig. F5), indicating a higher general alignment of grains.

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