On the secular evolution of groundwater on Mars
Geophysical Research Letters, 36 (24):
L24803+ (Dec 18, 2009)DOI: 10.1029/2009GL041018
Abstract
We modeled the subsurface transport of H2O and CO2 on Mars in a two-dimensional pole-to-equator cross-section, starting with sudden surface freezing representing ancient climate
change. We find that excursions to low obliquity strongly drive ice sublimation and subsequent groundwater evaporation at
low latitudes. This creates a hydraulic gradient in the saturated zone that moves water equatorward and even sublimates the
base of high-latitude ice. Eventually, all H2O is lost at latitudes less than ∼30°. A subcryospheric vadose zone may be retained at higher latitudes, but ultimately only
a few monolayers of adsorbed water will be held. A subcryospheric phreatic zone is preserved in the same regions only where
lateral heterogeneity restricts horizontal fluid flow. The predicted contemporary state of Mars is drier and with groundwater—if
present at all—in different locations than previously considered.