Global patterns and vigor of ventilated hydrothermal circulation through young seafloor

Using an updated global heat flow dataset with >14 000 oceanic measurements, we revise the estimated global power deficit due to ventilated hydrothermal circulation. This study differs from previous estimates by taking into account (1) non-Gaussian statistics, (2) an improved seafloor age model, (3) a new plate cooling model calibrated directly to heat flow, and (4) the effect of sediment cover on the heat flow deficit and ventilated cutoff age. We obtain the maximum heat flow deficit (difference between predicted and observed) when the data are separated by seafloor areas with <400 m and ⩾400 m of sediment cover. The estimated power deficit (integrated heat flow deficit with respect to area) for areas of thin (<400 m) sediment cover is 7.8 TW and for areas of thick (⩾400 m) is 0.2 TW. The total power deficit, 8.0 TW with 50% of estimates falling between 5.0 and 10.0 TW, represents a ∼30% reduction in magnitude compared with previous heat flow and fluid flow based estimates. Regions with thick, ⩾400 m, sediment cover experience half the heat flow deficit for one-third of the duration (25 Ma) of regions with thin sediment cover (75 Ma). Based on this study, vigorous fluid exchange between the oceans and seafloor redistributes ∼30% of heat lost through young oceanic crust.