Difference between revisions of "AY Honors/Waterfalls/Answer Key"

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Notable waterfalls include:
 
Notable waterfalls include:
 
* '''[[Angel Falls]]''', the world's highest, in [[Venezuela]] in [[South America]]
 
* '''[[Angel Falls]]''', the world's highest, in [[Venezuela]] in [[South America]]
 +
* '''[[Iguaçu Falls]]''', in [[South America]], on the [[Iguaçu River]] on the border between [[Brazil]] and [[Argentina]]
 
* '''[[Victoria Falls]]''', the world's largest, in [[Africa]], on the [[Zambezi River]] on the border between [[Zambia]] and [[Zimbabwe]]
 
* '''[[Victoria Falls]]''', the world's largest, in [[Africa]], on the [[Zambezi River]] on the border between [[Zambia]] and [[Zimbabwe]]
 
* '''[[Niagara Falls]]''', the best-known in [[North America]], located on the [[Niagara River]] on the border between [[New York]], [[United States]], and [[Ontario]], [[Canada]]
 
* '''[[Niagara Falls]]''', the best-known in [[North America]], located on the [[Niagara River]] on the border between [[New York]], [[United States]], and [[Ontario]], [[Canada]]
 
* '''[[Cumberland Falls]]''', the only waterfall in [[North America]] featuring a "moonbow"; located in southeast [[Kentucky]]
 
* '''[[Cumberland Falls]]''', the only waterfall in [[North America]] featuring a "moonbow"; located in southeast [[Kentucky]]
 
*'''[[Rhine Falls]]''', [[Europe]]'s largest, located in [[Switzerland]]
 
*'''[[Rhine Falls]]''', [[Europe]]'s largest, located in [[Switzerland]]

Revision as of 17:05, 21 August 2002

A waterfall is a geological formation resulting from a stream flowing over an erosion-resistant rock formation that forms a sudden break in elevation.

Some waterfalls form in montane environments where erosion is rapid and stream courses may be subject to sudden and catastrophic change. In such cases, the existence of the waterfall may not be due to the end product of many years of water action over a region, but rather the result of relatively sudden geological processes such as thrust faults or volcanic action.

Most waterfalls are the result of many years' worth of action of water on the underlying strata. Typically, a stream will flow across an area of formations, and more resistant rock strata will form shelves across the streamway, elevated above the further stream bed when the less erosion-resistent rock around it disappears. Over a period of years, the edges of this shelf will gradually break away and the waterfall will steadily move upstream. Often, the rock strata just below the more resistant shelf will be of a softer type, and will erode out to form a shallow cave-like formation under and behind the waterfall.

Streams often become wider and more shallow just above waterfalls due to flowing over the rock shelf, and there is usually a deep pool just below the waterfall due to the kinetic energy of the water hitting the bottom.

Notable waterfalls include: