The end of equilibrium?

Abstract

An overview of the proceedings of the 1992 Geomorphology symposium on Geomorphic Systems several trends. First, there is a pervasive concern with the presence and nature of geomorphic equilibria. However, the focus is not on detection of a single, stable equilibrium condition for geomorphic systems, but on the behavior of systems away from equilibrium, the presence and prevalence of dis- and nonequilibrium forms, and the presence of multiple equilibria for a given systems. A second major theme is the nonlinear behavior of geomorphic systems. This nonlinearity provides a bridge between existing threshold concepts in the discipline and the emerging study of earth surface phenomena as complex nonlinear dynamical systems. In connection with this, the critical role of feedback mechanisms in geomorphic systems emerges as a third general theme. Finally, a number of papers implicity or explicity raise the possibility of universality -i.e., that there are universal properties of geomorphic system behavior independent of location- and time-specific controls. Taken as a whole, the symposium papers are interpreted as signalling the possible end of classic equilibrium studies in the sense of searching for a single or typical equilibrium response to a given set of processes or controls. Conceptual frameworks which emphasize, or at least include, nonequilibrium responses and multiple equilibria are on the ascension. Historical perspectives suggest that these new developments are not necessarily inconsistent with prevailing and traditional geomorphic thought.