Geomorphological Processes on Slopes in Southern Africa 2012

Slope Profiles

• Slope profiles can be divided into 4 general components: convex upper segment, cliff face or free face, straight segment, and concave segment at the slope base.

Components of Slope Profiles

• Convex upper segment (waxing slope): the upper surface that tends to become convex towards its edge with a free face.
• Cliff face or free face: an outcrop of bare rock that stands more steeply than the angle of talus heap at its base, derived from the weathering of the free face.
• Straight segment: having a constant gradient, also known as the angle of repose (rest) of talus derived from the free face, commonly called the talus or debris slope.
• Concave segment at the slope base (waning slope): talus broken down further, accumulates towards the valley floor, and concave upwards, also referred to as pediment, valley floor basement, or lower wash slope.

9 Unit Slope Model

• The 9 unit slope model was proposed by Dalrymple et al. in 1968, based on studies of dominant slope angles prevalent and the dominant processes identified on each of the nine components.
• Not all slopes would have all 9 units at any one time.