2007 Annual Science Report
University of California, Berkeley Reporting | JUL 2006 – JUN 2007
History and Evolution of Surface Water on Mars
The thermal history of a planet’s interior affects the hydrosphere (e.g., Clifford and Parker, 2001) and the release of volatile elements to the atmosphere. The thermal history can therefore be related to the hydrologic history of Mars. In Wang et al. (2006) we show how cooling of the interior can pressurize water in sub-cryosphere aquifers. The water pressure can become large enough to crack the cryosphere and cause large amounts of water to erupt on the surface. This process may have operated throughout Martian history
We have also developed numerical models for hydrothermal circulation near magma intrusions in order to determine the volume and rate at which liquid water can be released at volcanic centers. We find that for plausible ranges of permeability, hydrothermal circulation does not significantly affect the subsurface temperature distribution. However, large amounts of water can be forced to circulate through the shallow crust.
We have extended our scope to the icy satellites in the outer solar system where liquid water may be trapped below a solid ice shell. Erupting this liquid water to the surface is a challenge because liquid water is more dense than ice. We show that as these satellites cool, the thickening of the ice shell can pressurize subsurface oceans (Manga and Wang, 2007). As a prelude to the calculations in Manga and Wang (2007) we developed improved models for Europa’s interior (Cammarano et al., 2006) and consider the feasibility of using seismology to search for oceans (Panning et al., 2006). On all satellites ocean pressure will become large enough to fracture the ice shell. On Europa-sized objects, however, the water would still not erupt on the surface. On smaller satellites, such as Enceladus liquid water would erupt.
PROJECT INVESTIGATORS:Michael Manga
PROJECT MEMBERS:Chi-Yuen Wang
RELATED OBJECTIVES:Objective 1.1
Models of formation and evolution of habitable planets
Outer Solar System exploration