Duncan Hewitt

Hydrothermal and solutal convection in porous rock: structures, fluxes, and terrestrial and icy-moon applications

Density gradients in fluid-saturated porous rock drive convective flow through the pores of the rock, just like the motion of water in a pan on a hot plate, but usually over very much longer timescales because of the strong damping associated with porous flow. In this seminar, we use theoretical modelling and numerical simulation to consider some basic features of convective flow in porous media, with a focus on the limit of ‘strong’ convection (which, typically, is still very slow). The associated fluxes and structures associated with the convective flow will be discussed, as will the role of geometric variation in the host rock; particular attention will be paid to layered media and the role of thin, low-permeability baffles, which are relatively common in sedimentary formations. Applications of this work to the convective dissolution of geologically sequestered carbon dioxide will be discussed, as will extensions to consider the role of hydrothermal (porous) convection in transporting heat and nutrients on icy moons in the solar system, in particular Saturn’s moon Enceladus.