Comment: 25:54 - 26:57 (01:03)
Source: Annenberg/CPB Resources - Earth Revealed - 20. Running Water II: Landscape Evolution
Keywords: "James Sadd", landscape, humans, landform, desert, rainstorm, flood, wind, slope, "tectonic activity", "Grand Canyon", "Colorado River", stream, water, "Earth's surface"
Our transcription: The sequence of events that takes place in the evolution of landscapes is not completely understood.
This is in part because the processes that shape the land surface operate very slowly on a human time scale.
But there's no doubt that running water plays a significant role.
Landforms that have been shaped and modified by running water are found in nearly every terrestrial environment on Earth.
They're even abundant in deserts where sudden rainstorms and flashfloods can produce more geomorphic change in a few hours than many years of desert winds.
But there would be no running water on the Earth's surface without slopes.
And land slopes are both created and maintained by tectonic activity.
Indeed, the shape of much of the Earth's surface is the result of a constant competition between tectonic forces and the destructive effects of running water.
And nowhere is this dual between tectonism and running water easier to appreciate than here at the Grand Canyon, where the Colorado River continues to sustain the evolution of one of the most beautiful and distinctive landscapes on Earth.
Geology School Keywords