Old NID
140890
Millions of years ago, the rivers flowing westward across northern Brazil reversed course and began to flow toward the Atlantic. Thus the mighty Amazon was born.
Some have suggested that the about-face was triggered by gradual changes in the flow of hot, viscous rock deep beneath the South American continent. But new computer models hint that the U-turn resulted from more familiar geological processes taking place at Earth’s surface—in particular, the persistent erosion, movement, and deposition of sediment wearing away from the growing Andes.
Read Why the Amazon flows backward by Sid Perkins, Science magazine
Image: Jesse Allen/NASA (using SRTM data courtesy of Global Land Cover Facility/U. MD); River data: WWF HydroSHEDS Project
