The Western Amazon Was a Sea?

 

Image credit: Tacio Cordeiro Bicudo (University of São Paulo, São Paulo, Brazil)

At intervals during the Miocene (23.03 to 5.333 million years ago) the Caribbean ocean surged into the western Amazon, creating a continuous inland sea. Saltwater currents mixed with fresh water from torrential rains. 

Researchers believe that the periods of flooding were relatively brief. For the majority of the epoch, the ocean receded, leaving a freshwater megawetland of interconnected lakes.

Scientists have found sediments as well as a fossilized shark tooth and a marine mantis shrimp, consistent with two separate Caribbean flooding periods in the last 20 million years. The geological and biological evidence suggests that during the Miocene the western Amazon region was a massive wetland, twice the size of Texas.

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