1. Alluvial Fan Science Potential Kelin X. Whipple and Kelli Wakefield School of Earth and Space Exploration Arizona State University

2. Holden Crater from Moore and Howard (2005) Bajada: Apron of Coalescing Alluvial Fans

3. Common Elevation Alluvial Fan Margins (~2000m): Top LTLD

5. Bajada Traverse: Scientific Bonus Diversity, Context, Clay Source?, Depositional Environment through Time, Duration Wet Conditions

6. Science Value: Bajada Traverse Source-Area (Crater Wall) Materials Source-Area (Crater Wall) Materials Lithology, Mineralogy (clast/matrix), Weathering Lithology, Mineralogy (clast/matrix), Weathering Context for LTLD Context for LTLD Depositional Environment (relation to LTLD) Depositional Environment (relation to LTLD) Paleoclimatic Conditions (hydraulics, weathering) Paleoclimatic Conditions (hydraulics, weathering) Plausible Water Source(s) Plausible Water Source(s) Duration of Active Sediment Transport Duration of Active Sediment Transport Depositional Process Depositional Process Mudflow / Debris Flow – composition (water content) Mudflow / Debris Flow – composition (water content) Other Mass Flow? Other Mass Flow? Fluvial (gravel – boulder) – flow depth, grain size Fluvial (gravel – boulder) – flow depth, grain size Fluvial (sand – granule) Fluvial (sand – granule) Intermittency? Intermittency?

7. Relation to LTLD Layers exposed in every fresh crater Layers exposed in every channel ridge Contact/transition exposed in cliffs (see Full Res HiRise)?

9. Fans Common in Craters Late Noachian, Widespread within Latitudinal Band Excellent Context: Understand LTLD in General

10. Fluvial Fans Best Analog But Mixed Stream and Mudflow Fans Can be Less Steep

11. Flow and Sediment Transport Relations Constraining Environmental Conditions (Fluvial Fans)

12. Sandy channels Gravel channels Expanding Flow

13. Expanding Flow Model (bedload) Parker et al. (1998) Reduce: n = 3/2 (bedload); Terrestrial Fans (Stock et al., 2008), Experimental Fans No Dependence on g, D, or Flow Width!

14. Equilibrium Channel Model (bedload) Reduce: n = 3/2 (bedload); Critical Stress Dominant

15. Equilibrium Channel Model (suspended load, n = 5/2)

16. Required Water Volume (Fluvial) Required Water Volume (Mudflow) ~40x Less! 15-250(50)V f

17. Water Volume -> Formation Time ~10’s – 1000 years minimum (200 – 20000) [5% intermittency] Weakest link

18. Relation to LTLD Layers exposed in every fresh crater Layers exposed in every channel ridge Contact/transition exposed in cliffs (see Full Res HiRise)?

20. Calculation of Q w Empirical method by Irwin et al. (2005) Empirical method by Irwin et al. (2005) Q 2 = 1.9w 1.22 Q 2 = 1.9w 1.22 Correction for Mars: multiply by factor of Correction for Mars: multiply by factor of 0.76 (1.25 -1.22 ) to account for lower velocity on Mars for same discharge

21. Suspension-Dominated SandBedload-Dominated Sand Straight to Concave ProfilesConvexo-Concave Profiles Lines are Theoretical Prediction (no tuning of parameters)

22. Bedload-Dominated Sand Experiments Vary Qw Lines are Theoretical Prediction (no tuning of parameters)