Shape of a River - Geomorphology
Description (pg 2 of
Large-scale geologic forces such as uplift,
volcanic activity, and glacial erosion and
deposition shape the land over which rivers
eventually flow. As you would expect, a stream
flowing down the steep slope of a mountain appears
different from one running through a nearly flat
plain of glacial till. A stream flowing over
bedrock has different characteristics from one
flowing over a bed of sand. Geology sets the stage
for what is to come.
As draining water seeks out and establishes a
river channel, geomorphological forces are at work.
Over time, land may continue to move on a large
scale. Much of the Canadian Shield, for example,
continues to rebound from the weight of the
glaciers; in places the land continues to rise
several inches per century. In arctic or alpine
regions, glaciers may continue to advance or melt.
In geologically active areas, earthquakes or
volcanoes may alter streambeds.