Sediment column at the mouth of the Amazon River. Credit: NASA The Amazon River has been around for 11 million years ago and in its shape for the last 2.4 million years ago, according to a study on two boreholes drilled in proximity of the mouth of the Amazon River by Petrobras, the national oil company of Brazil. Until recently the Amazon Fan, a sediment column of around 10 kilometres in thickness, proved a hard nut to crack, and scientific drilling expeditions such as Ocean Drilling Program could only reach a fraction of it. Recent exploration efforts by Petrobras lifted...
