Figure 9. Preliminary results of in situ temperature measurements at Sites 994, 995, and 997. Triangles indicate measurements made with the Adara tool, squares are WSTP measurements, and circles denote data collected with a prototype probe designed by E. Davis and H. Villinger. The open squares correspond to anomalous temperature measurements obtained within the gas hydrate stability field at Site 994. Errors in temperature are estimated subjectively, based on the quality of the equilibration record and the magnitude of the correction applied to the raw data. Errors in the depths of the measurements have not yet been taken into account. The reported gradients were calculated from linear regressions weighted proportional to the inverse of the squared error. None of the thermal gradients are in equilibrium with the temperatures recorded at the mudline, and heat flow estimated using these gradients and laboratory thermal-conductivity measurements is more than 20% lower than determined during conventional surveys at the same Blake Ridge locations in 1992.
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