Saturday, April 25, 2015

Do you know why the Amazon River flows backwards?

Science already knew that, at some point, the Amazon river flowed in the opposite direction to the current. For a long time, geologists from around the world have tried to explain the phenomenon by which occurred this reverse flow of this gigantic river. According to Dr. Victor Sacek of the University of São Paulo, Amazonas runs up because of a land erosion.

Photo flickr by stuartmiller

Photo flickr by idua_japan

This was not so for 10 million years, when most of what is now the Amazon basin was drained by a river flowing from the west of the continent until ending in a giant lake that was at the foot of the Northern Andes. It was from this point that the water began to flow north to the current Caribbean Sea and, as the Isthmus of Panama had not yet been formed, the water then flowed into the western Pacific Ocean. The researcher shows in his study that the rise of the Andes may explain the inversion process in the Amazon River flow in corresponding time periods. As mountains rose, intercepted larger volumes of rain clouds, causing further erosion.

In beginning, the degree of the Andes elevation caused the outbreak of a channel to the east that, over time, became the Paleolake where emptied the Amazon during its course to the west. Later, however, the same process was slowed, as the erosion accelerated to convert the old lake in a series of wetlands, known today as Training Pebas. Although the huge swamps of Pebas possessed an ecosystem similar to what exists today, the accumulation of sediments made the region emerge to the point of precipitation being pushed to the other side.
Photo flickr by LilyIsland

Fonte: Science Direct and published by portaldoamazonas

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