How and when was the Amazon River formed? Geologists from Brazil and the Netherlands discovered

Since time immemorial, the Amazon has drawn the world’s attention for its beauty and natural wealth. However, the question of when exactly did the majestic Amazon river form has baffled scientists for decades.

Now, thanks to an innovative study carried out by researchers at the Universities of Amsterdam and Brasília, they have been new data revealed that sheds light on the mysteries of its origin.

Geological analysis as a key point

The study, recently published in the journal Global and Planetary Changeestimated that the formation of the Amazon River occurred approximately between 9 and 9.4 million years ago back.

This discovery is based on an exhaustive geological and palynological analysis of the sediment of the submarine fan of the Amazon River, located at its mouth on the coast of Pará, Brazil.

What is a palynological analysis?
It is a technique used in paleontology, archaeology, geology or biology, among other disciplines, to study pollen grains and spores found in samples of soil, sediments, rocks or fossils. The term “palynology” derives from the Greek “palin” (again) and “logos” (study), which means “to study again” or “study of pollen grains.”

You sedimentdeposited over millions of years and obtained from drilling to extract hydrocarbons at a depth of more than 4.5 kilometers, revealed a significant change in the nature of plant materials and remains in the late Miocene.

A change in river nutrition

This change indicates a transition in the river’s feeding regime, moving from the tropical plains of South America to an expanded basin that reaches the Andes mountain range, thus marking the transcontinental phase of the Amazon.

These new discoveries challenge previous datings, which placed the formation of the Amazon River between 1.5 and 2.5 million years ago. Professor Farid Chemale, from the University of Brasília, highlights the importance of this study, stating that “We were able to deduce the age of the river by studying changes in the composition of sediments in the Amazon River submarine fan”.

The Amazon is the largest and longest river on the planet

The Amazon River is one of the most impressive natural wonders in the worldwith an extension that winds through the dense Amazon rainforest.

With one estimated to be approximately 7,062 kilometers long, it is the largest and longest river on the planet. Its course crosses a large part of South America, from its source in the heights of the Peruvian Andes, near the city of Arequipa, to its mouth in the Atlantic Ocean, off the coast of Brazil.

The Amazon is not just a river of ecological but also cultural importance. Throughout its course, the river has been home to countless indigenous communities that depend on it for their sustenance and survival. Its influence extends beyond physical borders, connecting people and ecosystems along its path.

News reference:

Hoorn, C. et al. The Amazon at sea: Onset and stages of the Amazon River from a marine record, with special reference to Neogene plant turnover in the drainage basin. Global and Planetary Change, v. 153, 2017.