Origin of Inclosed Meanders on Streams of the Colorado Plateau

Abstract

Meanders more or less narrowly inclosed by canyon walls characterize certain parts of many streams of the Colorado Plateau. On larger streams, the meanders appear to have been inherited from a preceding well-advanced erosion cycle; they are intrenched with inappreciable change of plan where hard rocks immediately underlay the former valley, but are greatly modified or obliterated where weak rocks have been encountered in deepening the valley. On smaller streams inclosed meanders are restricted to parts of the course carved in hard rocks, and their form indicates origin by downward-lateral corrasion, possibly or probably during the present erosion cycle. In soft rocks the tendency to cut horizontally so widens and clears the valley that the stream flows in a very wide shallow channel which is relatively straight. The origin of these features is mainly controlled by the strength of the rocks and relative loading of the streams.