Strahler Companion Ch. This chapter considers how rock properties influence the landforms and drainage patterns produced by fluvial denudation. The earth's crust contains a variety of rock types which differ in their resistance to denudation.
More resistant rock tends to form uplands and ridges while weaker rock forms lowlands and valleys.
Rock layers can be tilted, folded and fractured by tectonic forces to produce a variety of rock structures. The tilt and orientation of rock layers and fractures are described by their strike and dip . In areas with horizontal strata and an arid climate, fluvial denudation produces vertical cliffs of resistant rock separated by gentler slopes of less resistant rock. These slopes surround flat-topped plateaus, mesas and buttes capped by resistant rock. Different rock types and structures tend to produce different drainage patterns or stream network characteristics.