Comment: 00:40 - 01:58 (01:18)
Source: Annenberg/CPB Resources - Earth Revealed - 20. Running Water II: Landscape Evolution
Keywords: introduction, "James Sadd", landscape, river, stream, "Grand Canyon", rock, landform, "Colorado River", valley, transportation, sediment
Our transcription: A close look at the Earth's intricate system of running water is a close look at the evolution of Earth's landscape.
As they continue to shape the land around us, rivers and streams leave behind evidence of their enduring power.
Unlike earthquakes and volcanoes, which can cause sudden change, running water works slowly, almost imperceptibly, in shaping Earth's landscape.
We usually think of the Grand Canyon in terms of its rocks and the fascinating story that they contain, one that spans almost half of Earth's history, but there's more to the Grand Canyon than rocks.
The Canyon itself is a geologically active feature, a changing and evolving landform that's a monument to the power of running water.
The Colorado River carved this enormous valley over the last nine million years; in fact, the River carries about half a million tons of sediment past any point of the Canyon every day.
No wonder this great River has been described as "too thin to walk on, but too thick to drink."
Geology School Keywords