MST system measurements were made on whole-round sections of cores from each hole to determine GRAPE density, compressional (P-wave) ultrasonic velocity, magnetic susceptibility, and natural gamma radiation (see "Explanatory Notes" chapter, this volume). Some cores showed a high degree of disturbance at this site because of flow-in.
Index properties (gravimetric density) were measured on one or two samples (volume = ~10 cm3) per working-half section on all cores from Hole 1078A using Method C (see "Explanatory Notes" chapter, this volume).
One or two ultrasonic compressional (P-wave) velocity and un-drained vane-shear measurements per section were conducted close to the position of the discrete samples. For the discrete P-wave pulse-transmission experiments, the modified Hamilton Frame transducer system was used.
Sampling interval for GRAPE density (Fig. 35), ultrasonic compressional wave velocity (Fig. 36), and magnetic susceptibility (Fig. 37A) was 2 cm for the upper 50 mbsf and was changed to 4 cm below 50 mbsf. MST data are included on CD-ROM (back pocket, this volume). Natural gamma radiation measurements (NGR) were incorporated in the MST measurements, with a sampling period of 30 s at 32-cm resolution (Fig. 37B). Magnetic susceptibility and natural gamma radiation show some similarities (Fig. 37A and Fig. 37B, respectively), which may be attributed to higher proportions of clay including magnetic particles (see "Lithostratigraphy" section, this chapter). GRAPE density generally correlates well with the discrete wet bulk density data (Fig. 35).
Discrete velocity measurements at Hole 1078A, determined with the Hamilton Frame, show velocities between 1460 and 1655 m/s (Fig. 36). The velocity profile is similar to discrete density measurements (see below), which display higher values of silty clays (see "Lithostratigraphy" section, this chapter). The ultrasonic signals were completely attenuated below 26 mbsf, although down to this depth, signals could be recorded with high signal/noise ratio. Discrete velocity values match well with the MST compressional velocities in the upper 7 mbsf and then diverge toward higher values (Fig. 36).
Results of discrete measurements of wet bulk density, porosity, and moisture content for Hole 1078A are presented in Figures 38A, 38B, and 38C, respectively (also see Table 13 on CD-ROM, back pocket, this volume). The density values vary between 1380 and 1750 kg/m3. Porosities decrease from 76% in the top section to <60% deeper in the hole. Between 0 and 25 mbsf, discrete density values are lower than those for the GRAPE measurements. Both data sets match very well between 25 and 40 mbsf; however, below 40 mbsf, discrete wet bulk density values are generally higher than GRAPE values. Both profiles are very similar in shape, revealing good coherence between the two types of measurements. Note the good correlation between the density and velocity profiles at this site.
The thermal conductivity profile at Hole 1078A was measured at a resolution of one every second core section (see "Explanatory Notes" chapter, this volume). The values show little variation between 0 and 40 mbsf and show a decrease below that depth associated with a higher scatter (Fig. 37C).
At Site 1078, the Adara tool was deployed to measure formation temperature. A preliminary analysis provided three data points, which were used to estimate a geothermal gradient of 46°C/km, but further analyses will be required to confirm this result.
An undrained vane-shear measurement was usually performed in the bottom part of each core section. The profile shows a gradual increase of shear strength down to 42 mbsf (Fig. 37D). Below 42 mbsf, values show higher scatter significantly, which may be dependent on the position relative to the top or base of the cores where degassing and voids are most pronounced and low vane-shear values are expected (core breaks are indicated in Fig. 37D for comparison). Maximum values may represent less disturbed sections; their increase indicates compaction with depth. The shear-strength profile reveals an overall match with the wet bulk density profile.