Previous studies noted the close association of geologically very recent lava flows and fluvial channels emanating from Cerberus Fossae. To assess these relationships, we outline a model of magmatic dike emplacement that involves 1) surface fractures and localized volcanic eruptions, 2) attendant cryospheric cracking to fracture the surface and release pressurized groundwater confined beneath the cryosphere, 3) effusion of water along a segment of the fracture to form Athabasca Valles, and 4) heating of the regions adjacent to the dike to cause melting and subsequent subsidence of the surface, forming late-stage pits and depressions. Previous estimates of the aqueous discharge were ∼1–2 × 106 m3 s −1. Our models show that this flux could be readily accommodated by flow through adjacent dike-related cryospheric fractures at water rise speeds of ∼60 m/s. The required aquifer permeability, however, is far larger than commonly encountered over similar depths and scales on Earth. This suggests that water may be transported in the subsurface by mechanism more efficient than porous flow, and/or that the previously proposed volume flux values are overestimates.
Wilson and post-doc Mitchell jointly provided the physical model and mathematical analysis, Head (Brown Univ.) the observations. The importance of geologically recent volcanic activity on Mars in causing release of plentiful water, currently present but trapped beneath the frozen crust, is documented. RAE_import_type : Journal article RAE_uoa_type : Earth Systems and Environmental Sciences