J. Geophys. Res. http://dx.doi.org/10.1002/jgre.20049 (2013)


Evidence for extensive volcanic activity on the surface of Mercury is at odds with suggestions that its mantle is too thin to sustain the long-lived convection needed to produce magmas. Numerical models, however, demonstrate that mantle convection can persist in a thin mantle and generate broadly distributed magmas on Mercury.

Nathalie Michel at Case Western Reserve University, USA, and colleagues used a mantle convection model to simulate the global thermal evolution of Mercury from its formation to the present day. They explored a range of possible scenarios within the geological, geochemical and geophysical constraints from data obtained by the spacecraft MESSENGER, which has orbited Mercury since 2011. The simulations show that sustained mantle convection was possible over much of Mercury's history, even if the mantle was as thin as 300 km, roughly 12% of the planet's radius.

Calculations of magma generation based on the results of the convection model show that high degrees of melting should have occurred early in Mercury's history. Also, volcanic activity could plausibly have occurred as late as one billion years ago, consistent with observations of Mercury's surface.