Amazon River

The Amazon is the second largest river in the world.  It is in South America and from its origin in the Andes Mountains to its Delta traverses Peru, Bolivia, Colombia, and Ecuador before reaching its destination in Brazil.

The Amazon River’s freshwater volume is one of the largest in the world.  It has more than 200 tributaries and water systems that flow into it than any other river in the world. (The Amazon River)


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The Amazon River region is composed of Precambrian fragments.  The Sierra de Carajás, in the Central Amazon province is the most important mineral province in Brazil. Its “greenstone belts” are about 3 billion years old, and represent the oldest rocks in the Amazon craton. (Phyorg.com).

During the Proterozoic, the main Amazon River flowed from east to west, emptying into the Pacific. Its source was in present day Africa.  After the collapse and the opening of the Atlantic during the Mesozoic, the South American Plate moved westward, where the Pacific Plate collided with Nazca, a region in the southern coast of Peru (Ward, P. 1995)

This collision lifted the Andes and interrupted the flow of the Amazon to the Pacific. Subsequently, large lakes were formed in the eastern part of the Andes, including the Belterra. A slight inclination of the South American continent to the east, led to the reversal of the course of the Amazon toward the Atlantic. During the Cenozoic, the Amazon and its tributaries, gradually carved a basin of the Amazon and today comprises plateaus, plains and valleys.

Map of the Amazon River drainage basin.

Map of the Amazon River drainage basin.

References for Amazon River

The Amazon River Retrieved on 1.12.2012 from:

http://www.mbarron.net/Amazon/factfile.htm

Phyorg.com

http://www.physorg.com/news80904129.html

Ward., P. (1995). Subduction cycles under western North America

during the Mesozoic and Cenozoic eras.  Geological Society of America.

Retrieved on 1/12/2912 from

www.tetontectonics.org/Publications/Ward1995SubductionCycles.pdf

Colorado Geology Photojournals Retrived on 1/12/2012 from:

http://www.cliffshade.com/colorado/tectonics.htm#collisions