America was linked before the previewed

2015/04/09 Carton Virto, Eider - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Geologia

Although it is recognized that the isthmus of Panama was born 3 million years ago, the consensus is not absolute. For example, various research has shown that the displacement of living beings from one side to the other was occurring much earlier. Now, led by researchers from the Universidad Andina (Colombia), a group of Colombian and Panamanian researchers have discovered geological evidence to affirm that the passage of the sea closed at least 13 million years ago.

It has been published in the journal Science and research focuses on sediments abandoned by an ancient river system. They are located in the north of Colombia, where have been found remnants of volcanic rocks that originally can only be from Panama. Through geocronological analysis, the researchers have concluded that the river system was formed 13-15 million ago, pouring its waters south of the volcanic arc of Panama. For this to be possible, there must be a land connection between the river basin and northern Colombia. According to the researchers, the maritime passage of Central America was already closed, almost entirely.

One of the reasons why the Panama isthmus was placed 3 million years ago is that it was then that there was the largest migration of living beings between the two Americas (Great American Biological Interchange, GABI). However, placing us 10 million years ago “gives meaning to other rare results”, according to Carina Hoorn, a researcher at the University of Amsterdam. In an analysis article published in Science highlights that the change of dates has important consequences in the models we had so far on oceanic traffic, climate and exchange of living things.