One mudline measurement plus six runs within the sediments to determine if in situ temperatures were made in Hole 1252A using the APCT tool (Table T9; Fig. F24). Data were modeled using the software program TFIT (as described in "Downhole Tools and Pressure Coring" in the "Explanatory Notes"), using measured thermal conductivities (see "Physical Properties"). Uncertainty in the extrapolated value of in situ temperature resulting from a subjective analyst picking of tp, ti, and tf is <0.02°C for these high-quality records. Uncertainty resulting from possible errors in measured values of thermal conductivity is also estimated to be ~0.02°C. Additional uncertainty results from uncertainty in instrument calibration (see "Downhole Tools and Pressure Coring" in the "Site 1244" chapter).
The resulting temperature estimates are shown in Figure F25. The slope and the seafloor intercept are relatively insensitive to whether or not the mudline temperature is included; both equations predict BSR depths to be within 5 m of the projected depth of the BSR, which is well within the uncertainty. However, if one considers that APCT 11 was used for all of these measurements and that the ice bath calibration of APCT 11 suggests that +0.513°C should be added to temperatures recorded by this instrument (see "Downhole Tools and Pressure Coring" in the "Site 1246" chapter), then this is the only site drilled during Leg 204 where the measured in situ temperatures are higher than those predicted for the pure methane stability/seawater stability boundary. Whether this observation is significant has yet to be determined.
No in situ pressure measurements were made at this site.
No pressure core sampler cores were taken at this site.
No HYACINTH pressure cores were taken at this site.