Martian Water on the Brain

Presenter: Brian Hynek, University of Colorado, Boulder
When: February 9, 2004 12AM PST

There is copious geological evidence for past water at or near
the Martian surface. However, the questions of when?, where?, how?, and
how much? remain debated and unanswered. I will talk about some of the
recent advances in understanding of water on Mars with particular
attention given to: (1) an early period of precipitation-fed surface
runoff, (2) Martian hematite, and (3) layered deposits and putative
paleolakes. Recent high-resolution data have shown drainage densities
from ancient river valleys across the Martian surface to be comparable to
those formed on Earth in precipitation-dominated environments. This,
combined with other observations, makes an early period or periods of
precipitation very probable. Martian hematite was most likely formed in
the presence of water, possibly in a hydrothermal environment, subsequent
to the “wet” early period. Finally, thinly layered deposits will be
discussed and a water-free origin best explains many of these features.
These three topics will illustrate the complexities of understanding the
past water budget of Mars and its spatial and temporal distribution.
Preliminary results from the Mars Exploration Rovers will be examined in
the context of these themes.

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