Four reliable determinations of downhole temperatures were made at Site 1175 using the Adara APC temperature tool and the Davis-Villinger temperature probe (DVTP). Table T21 summarizes the deployments, and the temperature data are shown in Figures F31 and F32.
In situ temperatures were estimated by extrapolation of the station data to correct for the frictional heating on penetration using an average thermal conductivity of 1.0 W/(m·°C). The estimated in situ temperatures from the mudline temperature and the four measurements define a linear gradient of 0.054°C/m in the upper 273.9 m (Fig. F33). For thermal conductivites of 1.0 W/(m·°C), vertical conductive heat flow at Hole 1175A would be 54 mW/m2. Assuming purely vertical conductive and steady state heat flow, we project in situ temperatures of ~22°C for 400 mbsf, based on laboratory measurements of thermal conductivity (see "Physical Properties").
Pressures were also recorded during the DVTP-P deployments (Fig. F34). As noted in "In Situ Temperature and Pressure Measurements" in the "Explanatory Notes" chapter, postcruise modeling and processing is required to estimate in situ pressures.