The Valley Network Record on Mars (Class 2)

LPSC Key Sessions onthe Mars Hydrological Cycle

• Tuesday Afternoon, Sess 251. Ground Ice and Climate Change {e.g., new Clifford et al. abs on water in the cryosphere}

• Wednesday Morning, Sess 401. Ancient Mars Crust

• Thursday Morning, Sess. 501. Mars Aqueous Processes

• Thursday Afternoon (3:15PM), Sess. 556. Martian Gullies

• Numerous posters!

What do we want to know in general?

• Intensity• Precipitation[?] rates?• Discharges?

• Persistence• Global or local activity?• Long-lived climate or short excursions?• Intermittency? One episode or many? Formation

Timescales…

• Environmental Requirements (and/or) Implications• Is an ‘ocean’ necessary to support a climate where it

rains or snows? Are large lakes good enough?

Main Topic Today:

• How long does it take to form the deltas for valley networks on Mars? How can we estimate this? Are the various methods reliable and consistent with other geological estimates?