Comment: 00:40 - 01:38 (00:58)
Source: Annenberg/CPB Resources - Earth Revealed 23. Glaciers
Keywords: introduction, "James Sadd", landscape, glacier, mountain, Alps, "Himalaya Mountains", Rockies, "Yosemite Valley", "Sierra Nevada", river, valley, lake, "North American Continent", "Great Lakes", loch, Scotland, agriculture, soil, China, "Soviet Union", Canada, "glacial ice", rock, silt, transportation, wind, "fertile soil", erosion
Our transcription: Some of the most picturesque landscapes on Earth owe their existence to glaciers.
There are many examples: spectacular mountain ranges such as the Alps, Himalayas, and the Rockies were sculpted by repeated glaciation.
Yosemite Valley, here in the Sierra Nevada Mountains, would have been just another nondescript river valley if glaciers hadn't carved it to its present shape.
Many of the world's most beautiful lakes were gouged out of hard rock by glaciers.
These include North America's own Great Lakes and the famous lochs of Scotland.
Even the great expanses of rich agricultural soils that blanket China, and the Soviet Union, Canada, and the United States owe their existence to glaciers.
Moving glacial ice pulverizes the underlying rock into silt-sized fragments.
This silt was eventually transported and concentrated by the wind into the vast fertile soils of today.
Geology School Keywords