Séminaire
Various lines of evidence suggest that Mars may possess a planetary inventory of water equivalent to a 1-km deep global ocean averaged over the planet's surface. Currently, only a few percent of this amount is found in visible reservoirs such as the Martian atmosphere and polar caps. The remainder is thought to reside in the subsurface, as ground ice, groundwater and hydrated minerals. Four billion years ago, the geologic evidence suggests that the distribution and state of water on Mars were substantially different, including the existence of a northern ocean that may have covered up to a third of the planet and supported a dynamic hydrologic cycle -- including episodic rainfall. This talk will address how the climatic and geothermal evolution of Mars is thought to have affected the distribution and state of water, and influenced the geomorphic evolution of the planet's surface. Insights provided by recent spacecraft missions, including the current Curiosity rover investigation of Gale crater, will also be discussed.