Heat loss and internal dynamics of Venus from lithosphere strength

Abstract

The absence of plate tectonics and the young surface age (0.3-1 billion years) of Venus have led to diverse geodynamic models for Venus. The energetics of the Venusian interior drive these models; however, the lack of direct constraints on surface heat flow hampers their quantitative assessment. Here we present a global heat flow model for Venus, as well as estimates of the total heat loss, obtained from an inversion of geophysical data, including lithospheric effective elastic thickness, crustal thickness, and radioactive heat production. Heat flow on Venus is lower and less geographically structured than on Earth, with an average of 31 mW m$^{-2}$, but with highs associated to rifts systems reaching values typical of active terrestrial areas. The obtained total heat loss is 11-17 TW, similar to estimates of the total radioactive heat production. Therefore, at present, Venus proportionally dissipates much less heat than Earth. Furthermore, the calculated crustal temperatures imply that crustal melting or eclogitization are not dominant processes in the Venusian crust.