Malin and Edgett, 2000 (Mars) Costard et al., 2002 (Greenland)

Gullies on Mars and Earth

PSP_002932_1445

Mangold: ‘Debris flows’• Some Levees (argues they are visible in

Fig. 1 & 2).• Cyclical sinuosity: Argues for ‘wet’• Nature of terminal deposits is not a

discriminating factor (wet v dry). Terminal slope may help discriminate if flow properties and inertia are correctly modeled.

5-m high flow, Jiangjia Gully, China (location referenced to by Coussot)

Repeat Time in this channel is roughly 9-10 events/yr. (Chen et al., 2005, Environmental Geology, 48, 771-777.

Image USGS/K. Scott, June 24, 1990

Stock and Dietrich, GSA Bulletin, 118, 1125-1148, 2006.

Discussion Points

• What are discriminating factors for recognizing debris flows?

• Flow magnitude/discharge in gullies?

• Are ‘typical’ flow characteristics inferred from images:

– debris flows, hyperconcentrated flows, or something more quiescent? [two-phase vs one-phase…]

– What is the formative flow conditions on gullied slopes? Is there a spectrum of behaviors?

– Mechanics of sediment incorporation…