The Isthmus of Panama is the fusing point between North and South America. The scientific debate concerns how long the Panama land bridge has been in existence. Up until the recent discovery of ancient river bedrock in northern Columbia, most scientists believed the isthmus to have emerged from the sea some three million years ago. New findings, however, date it some 10 to 15 million years earlier.
New evidence suggests a new truth. The results of a new study conducted by the Universidad de los Andes in Bogotá, Columbia published in the journal, Science, indicate geological evidence, the presence of small grains of the mineral zircon, debunks earlier theories about the age of the Panama land bridge. According to researchers, these small particles unearthed from prehistoric rock layers are estimated to be 13 to 15 million years old and they clearly imply the co-existence of the land bridge.
In the words of geologist Camilo Montes who led the study, “The land bridge has been used to explain a lot of global phenomena about three million years ago, but what we’re saying is the land bridge formed 10 million years before that. We contend that a bridge, perhaps a transient one, was present since 13 to 15 million years ago.”
Originally separated by a deep water channel known as the Central American Seaway , this body of cold water prevented the exchange of animal life between the two isolated continents. The Panama Canal Expansion Project, which began in 2007, is the largest of any undertaking on the canal since its original construction. The study exposed areas of land and riverbeds heretofore unexplored.
Montes and his colleagues discovered fossils of land animals not indigenous to the places where they were found. This suggested some connection to the two continents as much as 17 million years ago, although by themselves, fossils weren’t enough evidence to support the existence of a land bridge. The research team hit pay dirt, so to speak, when they traced the route of an ancient river system laden with crystals of zircons that had erupted from Panama’s volcanoes and deposited in Columbia.
The formation of the Isthmus of Panama permitted the blending of all the animals living on the two landmasses. From South America came a unique array of exotic creatures: bizarre marsupials, saber-tooth tigers, sloths the size of elephants, giant flightless birds, mammoths, porcupines, and armadillos as large as cars. The ancestors of modern bears, cats, dogs, horses, llamas, and raccoon all traversed the isthmus from north to south.
The formation of the Isthmus of Panama had an enormous impact on Earth’s climate and its environment and most scientists believe this tiny sliver of land is among the most significant geologic events to occur in the last 60 million years.
There is still much to learn about the Isthmus of Panama and Montes and his research team have only scratched the surface. Still, their results are formidable and noteworthy, helping to unlock one of the most enduring mysteries of the ancient world.