Natural gamma-ray emission (NGR), magnetic susceptibility, gamma-ray attenuation porosity evaluator (GRAPE, a density proxy), and P-wave velocity were measured on whole-round core sections (see "Physical Properties" in the "Explanatory Notes" chapter). All measurements were made to the base of the APC cores in Holes 1095A, 1095B, and 1095D to depths of 87.70 mbsf (Core 178-1095A-10H), 203.10 mbsf (Core 178-1095B-13H), and 84.68 mbsf (Core 178-1095D-9H), respectively. Whole-core P-wave measurements were degraded in quality below 203.10 mbsf in Hole 1095B because of drilling disturbance associated with XCB coring and the slightly smaller diameter of the core relative to that of the core liner.
Whole-core magnetic susceptibility was measured at 2-cm intervals (averaged over 2 s at each point). The raw data values range from 0 to 1400 × 10-5 SI units (see "Related Leg Data" in the Table of Contents; Fig. F33). Low-pass filtered data are presented with depth and age scales in Figures F34, and F35, respectively. After low-pass filtering (Fig. F34), susceptibility shows a positive correlation with the GRAPE density data. The filtered susceptibility also shows an excellent positive correlation with core intervals rich in silt turbidites (see "Lithostratigraphy"). In addition, magnetic susceptibility measurements were taken at 1-cm intervals using the Bartington magnetic sensor on three split cores (Cores 178-1095A-8H and 178-1095D-1H and 2H) with the aim of obtaining a more detailed susceptibility record to correlate with previously studied piston cores from the same sediment drift (Pudsey and Camerlenghi, 1998).
Gamma-ray attenuation was measured at 2-cm intervals (averaged over 2 s at each point). The raw data range from 0.5 to 2.5 g/cm3 (see "Related Leg Data" in the Table of Contents; Fig. F33). After low-pass filtering, which aids in cleaning the raw data, the range narrows to 0.9-2.0 g/cm3 (Figs. F34, F35).
Density estimated from GRAPE data rises to 1.82 g/cm3 at ~50 mbsf, then falls to ~1.6 g/cm3 at ~100 mbsf. The depth of this density drop corresponds closely to the base of lithostratigraphic Unit I (49.3 mbsf, Core 178-1095A-7H-1) (see "Lithostratigraphy"). Below 100 mbsf, the density is broadly constant at ~1.6 g/cm3, but it drops to between 1.2 and 1.4 g/cm3 at ~205 mbsf, which is potentially attributable to the switch to XCB coring (Core 178-1095B-14X-1, 205.0 mbsf) and a zone of intermittent poor core recovery (between 200 and 295 mbsf). However, the drop in density corresponds to a drop in the downhole logging density (see "Downhole Measurements") and to a reflection in the vertical seismic profile (VSP) seismic records (see "Seismic Stratigraphy"). GRAPE-estimated density remains constant at ~1.6 g/cm3 down to ~380 mbsf, where it gradually increases to reach ~1.7 g/cm3 at ~480 mbsf. At this depth, the record is truncated by poor core recovery.
Superimposed on these broad trends are peaks in the filtered data that show a positive correlation with the magnetic susceptibility data and correspond to intervals rich in silt laminae (see "Magnetic Susceptibility").
Whole-core P-wave measurements were recorded continuously only down to 281.54 mbsf (Core 178-1095B-21X) in Hole 1095B, after which sediment disturbance, related to XCB coring, was too great for measurements to be reliable. Raw P-wave velocity data include short (1-5 cm) runs of high values close to the ends of core sections and several unrealistically low values (~1100 m/s). The anomalously high values at the section ends may result from core disturbance as well as from the influence of the core caps, and thus they were removed. See "Related Leg Data" in the Table of Contents for the raw data set; the cleaned data, which omit anomalously high and low values, are presented in Figure F33.
MST P-wave velocity increases downhole, matching the increase in bulk density indicated by the index properties (compare Figs. F33 and F36). Superimposed on this velocity trend are peaks that correlate with core intervals rich in silt laminae (see "Lithostratigraphy"). Velocities continue to increase below 200 mbsf. This change is unlikely to be an artifact of XCB coring (core disturbance should cause a decrease in velocities). Broad trends in the velocities agree well with in situ interval velocity estimates obtained from the WST (see "Downhole Measurements").
Whole-core natural gamma-ray emissions (averaged over 15 s) were counted at 15-cm intervals. The change to XCB coring caused no alteration in the signal. See "Related Leg Data" in the Table of Contents and Figure F33 for the raw data set.
The filtered gamma-ray count (Figs. F34, F35) shows an overall decrease with depth. Between 270 and 300 mbsf, the gamma-ray count decreases sharply from ~13.5 to 7 cps, which is not matched in the downhole log measurements (see "Downhole Measurements"). Neither this decrease nor the less pronounced variability in the record correlates with other physical properties, the downhole log data, or the lithostratigraphic record. The low at 280-300 mbsf matches an interval of low sedimentation rate, but this is not repeated elsewhere in the record and is not associated with a higher biogenic component.
Gravimetric and volumetric determinations of index properties were made for 60 samples from Hole 1095A and 273 samples from Hole 1095B. One sample was taken per core section. Samples were not taken in the reconstituted sediment surrounding biscuits in the XCB cores or in regions of flow-in in the APC cores. Wet mass, dry mass, and dry volume were measured, and from these measurements percentage water weight, porosity, dry density, bulk density, and grain density were calculated (see "Physical Properties" in the "Explanatory Notes" chapter, and "Related Leg Data" in the Table of Contents).
A comparison of bulk density values from the GRAPE and the index properties bulk density values (Fig. F36) shows a positive correlation, in which the GRAPE bulk density is constant at ~1.6 g/cm3 from 100 mbsf downward, and the index properties bulk density is constant at 1.75 g/cm3 from the same depth. The index properties grain density measurements are seen to decrease slightly with depth (Fig. F37). Therefore, the steady bulk density downhole is attributed to compaction and/or diagenetic processes.
Porosity decreases downhole linearly between 20 and 500 mbsf from ~60% to 56% (Fig. F37); similarly, the bulk water content (Fig. F36) decreases from 38% to 32% within the same depth range. This decrease with depth is expected and can be attributed to increased compaction under load.
Discrete P-wave measurements using all three sensors (PWS1, PWS2, and PWS3) of the velocity-strength system were made on cores from Site 1095. The upper 80 m of Cores 178-1095D-1H through 9H were soft enough to use the penetrative transducer pairs of PWS1 (direction of measurement = longitudinal, spacing of transducers = 69.5 mm) and PWS2 (direction of measurement = transversal, spacing of transducers = 34.8 mm). The PWS1 and PWS2 transducers were placed in a cross-like pattern at the same depth location to allow an evaluation of sediment anisotropy. Additionally, Hamilton Frame measurements (PWS3) were performed at the center of the cross formed by the PWS1 and PWS2 transducer imprints to assess the variability between all three transducers. Results of all three measurements are shown to the same depth scale in Figure F38 (average measurement separation = 1.8 m). Except for a two-data-point excursion at 20 m, all velocity values are in close agreement. We observe a more consistent difference in velocity between the longitudinal (PWS1) and transverse (PWS2) direction. Within the upper 50 m, the transversal P-wave velocity is in general slightly smaller than the longitudinal velocity. The average anisotropy index for the upper 50 m is -0.0038 (see "Physical Properties" in the "Explanatory Notes" chapter for the equation). Below 50 mbsf, the transverse velocity generally exceeds the longitudinal velocity, expressed in a positive average anisotropy index of 0.012.
Hamilton Frame (PWS3) measurements (average measurement separation = 1.7 m) were made on Cores 178-1095D-1H through 9H and 178-1095B-14X through 52X, spanning the interval from 210 to 560 mbsf (Fig. F38). No discrete P-wave velocities are recorded for the depth interval 83-210 mbsf. The strong increase in P-wave velocity below 500 mbsf can be correlated with an increase in density (Fig. F34) and is therefore thought to represent a real feature. Data presented in the "Related Leg Data" section of the Table of Contents include corrections made to data from the depth intervals 56.52-82.52 mbsf and 359.3-414.84 mbsf. The error resulted when the distance readings of the transducer heads lost calibration and were corrected by linearly shifting the depths of the data sections.