Geographical Cycle

The geographical cycle, also called the cycle of erosion or the Davisian erosion model, is a theoretical model describing how a landscape evolves over a long span of geological time through a predictable sequence of stages once a region is uplifted and erosion begins acting on it. American geographer and geomorphologist William Morris Davis proposed the model in an 1899 paper, describing an idealized progression from youth, marked by steep, narrow, V-shaped valleys cut by a few actively downcutting streams, through maturity, marked by maximum overall relief and a fully developed branching drainage network, to old age, marked by low relief and broad, gently sloping valleys as the landscape is worn down toward a nearly flat surface Davis termed a peneplain. Davis intended the model as a deductive, largely qualitative framework for interpreting landforms rather than a strict prediction, and it proved highly influential in shaping the early development of geomorphology as a discipline. The model was substantially critiqued and largely superseded over the twentieth century for treating tectonic uplift as a single episodic event followed by a long period of undisturbed erosion, rather than the more continuous and complex interplay of uplift and erosion now understood to shape most real landscapes.