The Mississippi River bisects the United States and separates the East from the West. It has figured prominently in much of the country's history. But it was here long before any people were. Research in just the last few years has revealed that the river is much older than the previously thought 20 million years. It appears the river was born 70 million years ago!
Still, 70 million years ago the Mississippi was nowhere near as large as it would become. [Geologist Michael] Blum has detailed how the waterway grew as it added tributaries: the Platte, Arkansas and Tennessee rivers by the late Paleocene, then the Red River by the Oligocene. Around 60 million years ago, the Mississippi was collecting water from the Rockies to the Appalachians; by four million years ago, its watershed had extended into Canada, and the Mississippi had grown to an enormous size, carrying four to eight times as much water as it does today, Cox and colleagues have found. “This was a giant river, on the order of the Amazon,” said Cox.
Learn how the mighty Mississippi was born, and how it has changed, at Smithsonian.
(Image credit: NASA/Jesse Allen)