CLARENCE DUTTON: ISOSTASY AND GEOMORPHOLOGY REVISITED

Claence Edward Dutton (1841-1912) was one of several scientists who laid the foundations of modern geology from their research in the American West during the late nineteenth century. Lacking the flamboyance of John Wesley Powell or the lifelong commitment of Grove Karl Gilbert, Dutton nevertheless made lasting contributions to physical geology, as well as to volcanic geology and seismology. While his scientific acumen is evident in reports on the plateaus and canyons of the West, his name is still often linked with the concept of isostasy, a term he coined in 1889 to reflect the debate then raging concerning Earth's crustal equilibrium. However, it was Dutton's description of the great denudation of the Colorado Plateau, rather than its isostatic implications, that came to influence geomorphology during the earlier twentieth century. Prolonged denudation was the necessary precursor to peneplanation, the end stage of Davis' cycle of erosion. Further, in an ideal cycle, initiated by rapid uplift and followed by lengthy structural quiescence, isostatic adjustments to denudation were an unnecessary complication. Localized isostatic responses to ice loading and delta sedimentation could be tolerated as special circumstances but large-scale responses to denudation were better ignored. The subsequent demise of Davisian geomorphology, triggered by advances in the understanding of plate tectonics, geomorphic processes, and geochronology, led to a reawakening of interest in isostasy as a concept basic to the explanation of Earth's surface relief. Somewhat belatedly, the Colorado Plateau and the American West, together with other regions characterized by active tectonism and rapid denudation, are once again at the center of the debate regarding denudation and crustal behavior.