The Eastern Amazon was submerged in waters twice at about a million years each time when it happens. Scientists from the Smithsonian Institute suggests that as the Andes rose, the water from the Caribbean surged through Venezuela all the way to northwest Brazil. The team found evidence such as shark tooth, mantis shrimp and other marine specimens in the area. These cements the controversy regarding the geological history of the Amazon.
According to Carlos Jaramillo, lead author of the research, they stumbled upon the theory by observing the oil wells in Colombia and the outcrops in northwest Brazil. They initially had a conflicting theory with the geologists who disagree about the nature of the sediments in the Amazon. However, they suggest that there was a brief submersion that happened twice between 18 to 12 million years ago, Phys.org said.
Even up to date, there are conflicting theories about the history of the Amazon. Some of the most popular notions are the blanket of a shallow sea, a huge freshwater lake, shifting rivers, and so on. However, none of them are conclusive. In fact, the idea of a para-marine meta-lake has no modern counterpart. At any rate, these theories are not yet totally ruled out.
This led to Jaramilla in assembling a huge team of top university authorities who shed light on the Amazon past, according to EurekAlert. Apart from the discovery of marine life specimens, the team has included tens of thousands of marine pollen grains. They dug up these specimens from two layers which sandwiched a non-marine pollen type, suggesting a brief respite from the flood, only to be flooded again.
Meanwhile, Jaramillo stressed that it is important to study the prehistoric geological events in the Amazon. First is the benefit of knowing the changes in the Amazonian landscape since millions of years ago. Secondly, the ancient climate shifts may also prove beneficial in understanding the current climate.
