1. Martian Water Ben Farley University of Massachusetts, Amherst December 1, 2003

2. Overview Water on Mars? What’s left? Where did it go? What does it mean?

3. Water on Mars?

4. Martian Oceans –Northern Hemisphere is topographically lower than Southern Hemisphere –Wrinkle ridges in North appear to be smoothed –North is mostly lower Hesperian in age, while South is Noachian

5. Water on Mars? Martian Oceans –Arabia GEL of 599 m –Deuteronilus GEL of 130 m –Vasitas Borealis Formation GEL of 156 m Vasitas Borealis Formation

6. Water on Mars? Fluvial Features –Teardrop islands –Gullies –Outflow Channels

7. What’s left? Gullies –97% located between ±30-60º latitude –Consistent with groundwater stable beneath megaregolith –Not consistent with Mellon and Jakosky model Polar Caps –GEL of 20-30 meters

8. What’s left? Hydrogen enriched soil

9. Where did it go? GEL of 20-30 meters in polar caps GEL of 50 meters escaped atmosphere GEL of 80 meters unaccounted for

10. Where did it go? Volatile rich deposits Ground water (sub-megaregolith)

11. What does it mean? There is water on Mars now There probably was an Ocean on Mars during the Noachian period