Shipboard physical properties measurements were performed on both unsplit and split cores recovered from Site 1085. Measurements with the MST were made of GRAPE density, magnetic susceptibility, and P-wave velocity at a high resolution on all recovered whole-round core sections. Natural gamma radiation (NGR) activity was determined on most of all cores at a lower resolution.
Gravimetric wet bulk density, porosity, and moisture content data were collected using samples from one or two points in every section <460 mbsf. Below 539 mbsf, this sampling rate was reduced to one data point for every second section. No samples were collected between 460 and 539 mbsf. Method C was also used at Site 1085 (see "Explanatory Notes" chapter, this volume).
Within all APC sections undrained vane shear strength was determined. No data were collected from the extended core barrel cores at this site.
Compressional (P-wave) velocity measurements were made at a resolution of one or two discrete sampling points per section. For discrete P-wave velocity measurements, the modified Hamilton Frame was used on split sections of cores to 222 mbsf.
Thermal conductivity was measured on every second unsplit section in every core by inserting a thermal probe into the sediment (see "Explanatory Notes" chapter, this volume).
GRAPE density (Fig. 31), P-wave velocities (Fig. 32), and magnetic susceptibility (Fig. 33A, Fig. 34A) were determined every 2 cm for depths <60 mbsf. MST data are included on CD-ROM (back pocket, this volume). NGR activity was measured every 30 cm. Below Core 175-1085A-8H, the resolution was reduced to 32 cm for the NGR sensor and to 4 cm for all other MST parameters. Compressional velocities were recorded at an amplitude threshold of 50 incremental units. The MST P-wave logger recorded signals to depths of 138 mbsf (Fig. 32), which was deeper compared with other Leg 175 sites. This observation may indicate a moderate content of gas in the sediments at Hole 1085A. MST velocity and discrete velocities display a similar trend between 0 and 67 mbsf, but discrete velocities are systematically higher. At 70 mbsf, both data sets merge, but the MST values reveal higher scatter down to 138 mbsf.
Magnetic susceptibility (Fig. 33A, Fig. 34A) and GRAPE density (Fig. 31) show a good correlation over the depth range of 540 mbsf. Below 540 mbsf, magnetic susceptibility sharply increases by a factor of 2 to 3. This increase in susceptibility is not associated with a change in wet bulk density values. NGR seems to be best correlated with magnetic susceptibility. The sharp increase in magnetic susceptibility below 540 mbsf is probably caused by a higher proportion of magnetic particles.
GRAPE density and discrete wet bulk density display a high degree of similarity, with some exceptions where data might be erroneous.
Discrete velocities decrease within the upper 5 m from 1660 m/s to 1560 m/s (Fig. 32). Between 22 and 28 mbsf, a high-velocity zone is observed with maximum velocities of 1700 m/s. A second peak interval can be identified between 37 and 39 mbsf. Density and velocity profiles do not correlate between 0 and 222 mbsf (Fig. 31A, Fig. 32). Because of the low gas content observed at Hole 1085A (see "Organic Geochemistry" section, this chapter), velocity data are considered to be more reliable than those at previous Leg 175 sites, where higher gas content compromised the quality of the P-wave velocity measurements.
Data from discrete measurements of wet bulk density, porosity, and moisture content are displayed in Fig. 35A, Fig. 35B, and Fig. 35C, respectively (also see Table 14 on CD-ROM, back pocket, this volume). The density values vary between 1500 and 1950 kg/m3.
The trend of the wet bulk density profile represents an overall increase in values from 0 to 600 mbsf, which is probably related mostly to compaction. The sediments consist mainly of carbonate-rich oozes, which change into a more clay-rich sediment facies, as imaged by the overall variation of wet bulk density and the lithostratigraphic boundaries (see "Lithostratigraphy" section, this chapter). In general, porosity and moisture profiles are inversely correlated with wet bulk density. Porosities decrease from 70% in the top section to 40% at 600 mbsf, indicating the high carbonate content of the sediments (Fig. 35B). Moisture content varies between 95% at the top of Hole 1085A and 26% at 600 mbsf (Fig. 35C). Local extreme values correspond to observed and identified lithostratigraphic units (see "Lithostratigraphy" section, this chapter).
The thermal conductivity profile (Fig. 33B, Fig. 34B) at Hole 1085A was measured in every second core section (see "Explanatory Notes" chapter, this volume). Values range between 0.8 and 1.15 W/(m·K), and thus were higher compared with any data from previous Leg 175 sites, where values typically varied between 0.75 and 0.9 W/(m·K). Below 300 mbsf at Site 1085, it was sometimes difficult to establish direct contact between the thermal probe and the sediments inside the core liners. Thermal conductivity and undrained vane shear reveal some similarity between 0 and 230 mbsf. The thermal conductivity profile is similar to wet bulk and GRAPE density profiles over longer depth intervals at Hole 1085A (Fig. 31).
In Hole 1085A, the Adara tool was deployed to measure formation temperature. A preliminary analysis provided two data points, which were used to estimate a geothermal gradient of 48°C/km, but further analyses will be required to confirm this result.
Undrained vane-shear measurements were performed in the bottom part of each core section between 0 and 230 mbsf (Fig. 33D, Fig. 34D). Below 230 mbsf, the deformation of the original sediment structure into individual drilling biscuits inhibited the measurements of reliable vane-shear data. The profile at Hole 1085A shows an overall increase in vane shear strength between 0 and 215 mbsf, with a maximum value in shear strength measured at 215 mbsf.