Index properties measurements were made at a resolution of one sample for every two sections in the cores from Holes 1120B and 1120D. Index properties were determined by a gravimetric method (see "Physical Properties" in the "Explanatory Notes" chapter). Values of measured index properties (void ratio, porosity, water content, bulk density, and grain density) are presented in Table T15 (also in ASCII format). The properties show little variation downcore, indicating a relatively homogeneous section (Fig. F16). There was good correlation in an overlapping section between the deeper part of the core in Hole 1120B and the upper part of the core in Hole 1120D.
The shipboard physical properties program at Site 1120 included nondestructive measurements of bulk density, magnetic susceptibility, natural gamma-ray activity, and P-wave velocity on whole sections of all cores using the multisensor track (MST) (Fig. F17). Magnetic susceptibility was measured at 4-cm intervals and at high sensitivity (4-s measurement time) in all Site 1120 holes. Magnetic susceptibility is generally low but has occasional anomalously high values, especially in the deeper sections of the core. Natural gamma-ray activity was measured with a 15-s count every 14 cm in Holes 1120A, 1120B, 1120C, and 1120D. There is little variation downcore except in the upper part of the core (<15 mbsf), where high-amplitude fluctuations occurred. Gamma-ray attenuation porosity evaluator bulk density measurements were made at 4-cm intervals at all Site 1120 holes. The GRAPE bulk density measurements in Hole 1120D show a zone ~2 m thick that has significantly lower density values. Data from Hole 1120D correlate well with data from Hole 1120B and give indications of the nature of the unrecovered core (~17 to 22 mbsf) in Hole 1120B (Fig. F18) (see also "Composite Depths"). The zone of low-density sediment suggests that the lack of recovery in Hole 1120B may have been a result of unconsolidated sediment that was not retained by the core catcher.
The P-wave velocity measurements (PWL) were made at 4-cm intervals for Holes 1120A, 1120B (Cores 1H-7H), and 1120C but gave poor results.
Measurements of shear strength, using a mechanical vane, were made on split cores from Hole 1120B (Fig. F19). Samples were generally taken in fine-grained sediments at a resolution of one per section from Hole 1120B. Shear-strength measurements were taken using the Torvane method on cores from Hole 1120C at a resolution of one for every other section. No samples were taken from the XCB cores. Values are generally low with a range of near 0 to 25 kPa, indicating predominantly unconsolidated sediments. Shear-strength values obtained from the Torvane method correlate well with those from the vane shear test.
Compressional-wave velocity was measured parallel to the core axis on split cores from Holes 1120B and 1120D using the digital sound velocimeter system. These measurements gave better results than the MST. There was good correlation of the values between the lower portion of Hole 1120B and the upper portion of Hole 1120D, indicating ~30 m of overlapping section. P-wave velocities range from 1540 to 1640 m/s.
Only one downhole temperature measurement was taken with the Adara temperature tool at the position of Core 181-1120B-6H, and temperature values were measured at two points in the coring process: the mudline and 45.9 mbsf (Fig. F20). At 45.9 mbsf, the Adara temperature tool measured a value that reached 17.5° C just after penetration because of the effect of frictional heat production; in the same location, and at near equilibrium with the in-situ sediments, it recorded 6.6° C just before pulling out. Thermal conductivity was measured in the shipboard laboratory on the same core where the Adara temperature tool was used; four measurements were made per core. The Adara temperature tool yielded good quality data; the results for Core 181-1120B-6H indicated a temperature of 8.877° C ± 0.18° C at 45.9 mbsf, and 6.244° C ± 0.02° C at the mudline, based on temperature equilibration curves. A thermal gradient of 5.74° C/100 m was then calculated from the two measurements. Using an average thermal conductivity of 1.29 W/(m·K) in Core 181-1120B-6H, heat flow was estimated to be 0.074 W/m2. The thermal gradient and the estimated heat-flow value are similar to those determined from sediments recovered from the Weddell Sea (Barker, Kennett, et al., 1988), consistent with a similar age for the crust underneath both locations. However, the values were only determined from one Adara temperature profile and should be used with caution.