1. The Valley Network Record on Mars (Class 2)

2. LPSC Key Sessions on the Mars Hydrological Cycle Tuesday Afternoon, Sess 251. Ground Ice and Climate Change {e.g., new Clifford et al. abs on water in the cryosphere}Ground Ice and Climate Change Wednesday Morning, Sess 401. Ancient Mars CrustAncient Mars Crust Thursday Morning, Sess. 501. Mars Aqueous ProcessesMars Aqueous Processes Thursday Afternoon (3:15PM), Sess. 556. Martian GulliesMartian Gullies Numerous posters!

3. 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?

4. 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?