Geomorphic systems of North America / Геоморфологические системы Северной Америки

Geomorphology is the study of earth-surface processes and forms. As a component of the fields of geology and geography, geomorphology is particularly concerned with change: progressive changes through time or changing spatial distributions at the earth’s surface. Geomorphology as a science views the objects of its study as collections of elements in complex systems that are groupings of forms and related processes. Because these groupings have regional manifestations strongly controlled by geologic materials and structures, the geomorphic systems of North America have a definable regional expression that serves as a method of organizing knowledge. The Geological Society of America’s publication series celebrating the Decade of North American Geology and the Centennial of the founding of the organization is generally organized according to geographic regions, so it is appropriate that this companion volume to the series also adopts a regional framework (Figs. 1 and 2).

The geomorphologic divisions of the continent depicted in Figure 2 are broad generalizations. Discussions in subsequent chapters that more specifically define the extent of each division use boundaries suggested by workers several decades ago. In the United States, for example, the modern geomorphologic divisions derive from the efforts of Neville M. Fenneman, who in 1913 proposed to the Association of American Geographers that geomorphic divisions would be useful in research (Fenneman, 1914). Later, a committee chaired by Fenneman and consisting of M. R. Campbell, F. E. Matthes, Douglas Johnson, and Eliot Black-welder produced a map with three orders of geomorphic divisions for the United States, which was adopted by the U.S. Geological Survey. Its use has continued with only slight modifications. Fenneman (1928) provided an accompanying paper, which remains the definitive work on regional classification of geomorphic systems in the United States.
The emphasis in the following chapters is not on definition and description of regions, but rather on analyses of modern processes and forms. It is not possible, however, to completely separate geomorphology from Quaternary geology because some research questions addressing processes do so on time scales that extend into the middle and late Tertiary. While this volume <...>