The shipboard physical properties program at Site 1125 included nondestructive measurements of bulk density and magnetic susceptibility on whole sections of all cores using the MST (Fig. F18). Magnetic susceptibility was measured at 4-cm intervals and at high sensitivity (4-s measurement time) on core from all Site 1125 holes. High-amplitude fluctuations in magnetic susceptibility above 245 mbsf are associated with the occurrence of tephra layers (see "Lithostratigraphy"). The GRAPE bulk density measurements were made at 4-cm intervals in all Site 1125 cores. The GRAPE density increases gradually from a surface low of 1.6 to 1.85 g/cm3 at 188 mbsf. A break in the increasing trend at 188 mbsf may be related to a hiatus or a rapid change in deposition rate. The densities are generally low between 188 and 245 mbsf (245 mbsf is the boundary between lithologic Subunits IB and IIA) and correspond to high magnetic susceptibility values. With some exceptions, lithostratigraphic Unit II is characterized by a very flat density profile. Below 510 mbsf, the densities begin another gradually increasing trend down to 532 mbsf. An abrupt decrease in the GRAPE density at 532 mbsf corresponds to a similar decrease in the magnetic susceptibility record, possibly reflecting a depositional hiatus.
Five downhole temperature measurements were taken with the Adara temperature tool at the position of Cores 181-1125A-5H, 7H, 9H, 11H, and 13H. The Adara temperature tool yielded good quality temperature estimates of 6.54°C from Core 5H, 7.10°C from Core 7H, 9.25°C from Core 9H, 9.42°C from Core 11H, and 11.65°C from Core 13H (Fig. F19). Based on temperature equilibration curves from Cores 5H, 7H, 9H, 11H, and 13H, the temperature estimate at the mudline is 3.60°C. Thermal conductivity was measured in the shipboard laboratory on the same core as the Adara temperature tool was used in; four measurements were made per core. A thermal gradient of 6.49°C/100 m was then calculated from the Adara and thermal conductivity measurements. Using an average thermal conductivity of 1.09 W/(m·K), heat-flow was estimated to be 0.07 W/m2.