Introduction

A little more than a century ago, William Morris Davis described the form of the land as a function of three variables: structure, process and time (Davis, 1899). The statement is equally true for tropical landforms. Geology is usually the primary determinant of land: its elevation, steepness and stability. Understanding of tropical landforms should start with an introduction to the geological framework. The distribution of tectonic mountains that produce large quantities of sediment; stable areas underlain by old rocks (cratons) that produce very little; and large river valleys where the sediment is temporarily stored while being transported to the sea are all determined by plate tectonics. A familiarity with the distribution of plates and their boundaries in the tropics is necessary to understand regional landforms and operating processes.