A minimum program of shipboard physical properties measurements was carried out at Site 1087. Measurements with the MST were conducted at a 10-cm resolution for GRAPE wet bulk density, magnetic susceptibility, and P-wave velocity on all recovered whole-round core sections.
Gravimetric wet bulk density, porosity, and moisture content data were determined from one sample point in every half-split core section. Method C was used at Site 1087 (see "Explanatory Notes" chapter, this volume).
Discrete compressional (P-wave) velocity measurements were made at a resolution of one sampling point per section. For these P-wave velocity measurements, the modified Hamilton Frame was used on split-core sections between 0 and 255 mbsf.
Thermal conductivity was determined on every fifth unsplit section in every core by inserting a thermal probe into the sediment (see "Explanatory Notes" chapter, this volume).
GRAPE density (Fig. 19), P-wave velocity (Fig. 20), and magnetic susceptibility (Fig. 21A) were recorded every 10 cm for the entire depth at Hole 1087A. MST data are included on CD-ROM (back pocket, this volume). Compressional velocities were stored at an amplitude threshold of 50 incremental units. The MST P-wave logger recorded signals over the entire depth range of 255 mbsf at Hole 1087A (Fig. 20), which correlate well with discrete velocities. Discrete velocities were generally higher (Fig. 20), although MST velocities are higher between 170 and 205 mbsf.
Magnetic susceptibility (Fig. 21A) shows a trend similar to that of GRAPE density and index properties wet bulk density (Figs. 19, 22A) over some depth intervals. A zone of high variability in elevated magnetic susceptibility values occurs between 65 and 75 mbsf (Fig. 21B).
GRAPE density and index properties wet bulk density display a high degree of similarity. GRAPE density varies from 1530 kg/m3 to 1900 kg/m3. The overall increase in density is caused by compaction. Intermediate variability in GRAPE density may correspond to lithologic boundaries (see "Lithostratigraphy" section, this chapter). Similar to Site 1086, higher values in GRAPE density than in wet bulk density can be observed over the entire depth range at Site 1087.
Discrete velocities (Fig. 20) decrease within the upper 10 m from 1600 to 1540 m/s. The higher velocities in the top portion of Hole 1087A may be caused by coarser grained particles (see "Lithostratigraphy" section, this chapter). Below 10 mbsf, velocity values increase in correspondence to GRAPE and index properties wet bulk density values.
Between 0 and 255 mbsf, most of the MST P-wave values are lower than the discrete velocities (Fig. 20). Similar to Hole 1086A, much lower gas content was observed at Hole 1087A (see "Organic Geochemistry" section, this chapter), which resulted in less disturbed sediments.
Data from discrete measurements of wet bulk density, porosity, and moisture content are displayed in Fig. 22A, Fig. 22B, and Fig. 22C, respectively (also see Table 12 on CD-ROM, back pocket, this volume). Wet bulk density values vary between 1500 and 1810 kg/m3, indicating a coarser grain-size distribution in the sediments compared with the clay-rich sediments from other Leg 175 sites.
The wet bulk density profile shows an overall increase which is mostly associated with compaction. Hole 1087A consists mainly of foraminifer-nannofossil ooze (see "Lithostratigraphy" section, this chapter), which is reflected in generally higher values of wet bulk density and velocity.
In general, porosity and moisture profiles are inversely correlated with the wet bulk density. Porosities decrease from 68% in the top section to 53% at 255 mbsf (Fig. 22B). Moisture content varies between 44% at the top of Hole 1087A and 32% at 255 mbsf (Fig. 22C).
The thermal conductivity profile (Fig. 21B) at Hole 1087A was measured in every second and fifth core section above 40 mbsf and in every fifth core section below (see "Explanatory Notes" chapter, this volume). Values range between 0.8 W/(m·K) at 22 mbsf and 1.2 W/(m·K) at 50 mbsf. Higher variability in thermal conductivity values can be observed between 0 and 76 mbsf, whereas below 76 mbsf, variations in thermal conductivity are much less pronounced. Similarity between the thermal conductivity profile (Fig. 21B) and magnetic susceptibility exists (Fig. 21A). Thermal conductivity values vary in the same range as those at Sites 1085 and 1086.
At Hole 1087A, 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 52°C/km, but further analyses will be required to confirm this result.