Manaus Agile tourism and culture of the AmazonAmazon River
Scientists from UnB (University of Brasilia) and the University of Amsterdam have concluded that the age of the Amazon River is between 9.4 million and 9 million years old. The results were published in the journal Global and Planetary Change this week.
Estimates proposed in recent literature said the river would be younger (about 2.6 million years) and an earlier study based on this same drilling talked about 1 million to 1.5 million years.
The new study performed a geochemical analysis and palynology (study of pollen grains and spores) of sediments from a marine hydrocarbon exploration drill hole that reached 4.5 km below sea level. "We applied high-resolution analysis techniques that had not been used before in the region," says Farid Chemale, one of the researchers involved in the study.
They observed a different change in the composition of sediments and plant waste matter during the late Miocene period (9.4 to 9 million years). This represents a change in the river area from the tropical lowlands to the upper Andes, revealing the beginning of the Amazon River.
The world's largest basin
The Amazon River contributes one fifth of the oceans water supply and has the largest river basin in the world. The beginning of the river represents a defining moment in the reorganization of the paleogeography of South America, forming both a tip and a divide for the biota in the Amazonian landscape.
The history of the Amazon River and basin are difficult to unravel, as continental records are scarce and fragmented. The marine records are more complete, but access to them is difficult.
Sediments in the vicinity of large rivers often hold continuous records of terrestrial material accumulated by the river over time. These records provide key material for the study of climate, geography, and the evolution of the Earth's biome.
The research is part of the Clim-Amazon project, which unites Brazilian and European scientists to study climate and geodynamics of the sediments of the Amazon River basin.
Source: UOL Notícias
