The Isthmus of Panama has been blamed for everything from triggering never-ending ice ages to bringing bizarre creatures like the terror bird and the opossum to North America. Now, there's new geologic evidence that the narrow Panama land bridge emerged from the sea 12 million to 15 million years ago, much earlier than thought. This early uplift wreaks havoc with prevailing ideas, which suggest this strip of land established itself just 3 million years ago. "The land bridge has been used to explain a lot of global phenomena about 3 million years ago, but what we're saying is the land bridge formed 10 million years before that," said lead study author Camilo Montes, a geologist at the Universidad de los Andes in Bogotá, Colombia. Before the Panama land bridge formed, a deep-water channel linked the Pacific and Atlantic oceans along the equator. Closing the gap with the rise of the land bridge may have cooled the Earth's climate by changing ocean currents, thus trapping the planet in a repeated cycle of Northern Hemisphere glaciations, according to several studies. The swampy terrain also became a superhighway for animals crossing from North to South America and vice versa. http://news.yahoo.com/land-bridge-linking-americas-rose-earlier-thought-130351695.html

• published: 13 Apr 2015
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