Scientists discover Amazon river is 11 million years old

July 29, 2009

Satellite image of mouths of Amazon river in Brazil. Image: Wikimedia Commons

Researchers at the University of Liverpool have discovered that the Amazon river, and its transcontinental drainage, is around 11 million years old and took its present shape about 2.4 million years ago.

University of Liverpool researchers, in collaboration with the University of Amsterdam and Petrobras, the national oil company of Brazil, analysed sedimentary material taken from two boreholes near the mouth of the river to calculate the age of the Amazon river and the Amazon deep sea fan.

Prior to this study the exact age of the Amazon, one of the two largest rivers in the world, was not known. Until recently the Amazon Fan, a submarine sediment column around 10km thick, had proven difficult to penetrate. New exploration efforts by Petrobas, however, have lea to two new boreholes being drilled near the mouth of the Amazon - one 2.5miles (4.5km) below sea level - which resulted in new sedimentological and paleontological analysis of samples from the river sediment.

"River sediment records provide a unique insight into the palaeoclimate and geography of the hinterland," said Jorge Figueiredo from the University's Department of Earth and Ocean Sciences

"This new research has large implications for our understanding of South American paleogeography and the evolution of aquatic organisms in Amazonia and on the Atlantic coast. The origin of the Amazon river is a defining moment: a new ecosystem came into being at the same time as the uplifting Andes formed a geographic divide."

The study was published in the scientific journal, Geology, in July 2009.

Source: University of Liverpool (news : web)

• RayCherry - Jul 29, 2009
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  I wonder if any human(oid) remains can be found amongst all that sediment where ancient peat 'bogs' formed. With all the vegetation so assist the formation of peat, and the river to attract all forms of animal life, some evidence should remain and could be as valuable, and as old, as that found in Africa in the last decade.
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• Klaus - Jul 29, 2009
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  Humans hadn't migrated to the West until about 20,000 - 30,000 years ago.
  
  
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• ThomasS - Jul 30, 2009
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  Was this not on physorg before? Im quite sure..
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• twango - Jul 30, 2009
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  And yet another story (2006) states uncategorically that "Amazon River Once Flowed in Opposite Direction" during a period "between 65 million and 145 million years ago."
  
  Science journalism doesn't do anyone a favor when it treats hypotheses as FACT. Failing to address such contradictions within 'news' only serves to confuse, discourage, and skeptify the public about science.
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