Epic Past of Highest Coastal Mountains Uncovered
The Earth's highest coastal mountain range — Colombia's Sierra Nevada de Santa Marta — has led a fascinating life. Violent collisions, wayward travels, birth and death all had a hand in the mountain's evolution, a new study finds.
Using the ancient magnetic field recorded in the mountain's rocks, researchers have traced the Sierra Nevada de Santa Marta's 1,367-mile (2,200-kilometer) journey from northern Peru to its modern position on the Caribbean coast of Colombia during the past 170 million years.
The rocks of the mountain reveal collisions with former super-continents, the birth and death of volcanoes, and a clockwise rotation that opened an entirely new rocky basin in the mountain range, which overlooks the Caribbean.
When ancient rocks cooled and crystallized after feeding volcanoes, the iron inside the rocks lined up with the earth's magnetic field, which is slightly different depending on one's latitude. A rock formed today in the Ecuador will have a magnetic orientation that differs from a rock formed in Peru or in Tierra del Fuego, said study team member Agustin Cardona of the Smithsonian Tropical Research Institute in Panama City, Panama. When the geologists looked at the rocks from Santa Marta, the magnetic properties they saw suggested, suprisingly, that the rocks were formed near Peru, Cardona told OurAmazingPlanet.
The work "fills a notorious gap in the picture of the region's geology," said Cardona.
The diverse rock record exposed in the Sierra Nevada de Santa Marta rests on an ancient foundation that is more than 1 billion years old. The rocks may be remnants of extinct volcanoes and mountains that once existed but were later obliterated by powerful geologic forces, the study suggests.
Other studies that were part of a four-year project to look at the mountain range's geological evolution revealed evidence of historic earthquakes and a large submarine canyon carved in the floor of the Caribbean Sea.
The findings are published in the October edition of the Journal of South American Earth Sciences.
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This article was provided by OurAmazingPlanet, a sister site to LiveScience.
