Deep-ocean temperature variations and implications for errors in seafloor heat flow determinations

The accuracy with which seafloor heat flow is determined depends on the temporal stability of bottom water temperature. Indirect tests for stability are provided most commonly by observing the uniformity of heat flow with depth. This criterion is met to a high degree of certainty at two sites in the eastern North Pacific Ocean, where colocated high‐quality probe and borehole heat flow data can be compared. A more direct test for stability is provided by long‐term observations of bottom water temperature. Previously published records and new data show temperature variations of only a few hundredths of a degree at sites in the central and eastern North Atlantic and the eastern North Pacific. Resultant gradient perturbations are geothermally insignificant (