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'Teenage' Andes could collapse 'Teenage' Andes could collapse
(30 minutes later)
By Victoria Smink BBC Mundo Growing pains for "young" Andes mean they could actually shrink By Veronica Smink BBC Mundo Growing pains for "young" Andes mean they could actually shrink
The Andes were formed 120 million years ago; but in geological terms, this giant of South America is more like a teenager going through growth problems.The Andes were formed 120 million years ago; but in geological terms, this giant of South America is more like a teenager going through growth problems.
A new study by a group of Argentine researchers suggests that the largest mountain chain on the American continent is not as quiet as it seems.A new study by a group of Argentine researchers suggests that the largest mountain chain on the American continent is not as quiet as it seems.
According to Folguera Andres and Victor Ramos, geologists in the Faculty of Natural Sciences at the University of Buenos Aires (UBA), some mountains are losing altitude.According to Folguera Andres and Victor Ramos, geologists in the Faculty of Natural Sciences at the University of Buenos Aires (UBA), some mountains are losing altitude.
"We found that parts of the Andes are undergoing a cycle of collapse which started some 6 million years ago," says Mr Andres."We found that parts of the Andes are undergoing a cycle of collapse which started some 6 million years ago," says Mr Andres.
The reduction in height is taking place in the Argentine provinces of Mendoza and Neuquen, but elsewhere the mountain chain is actually growing, for example in San Juan.The reduction in height is taking place in the Argentine provinces of Mendoza and Neuquen, but elsewhere the mountain chain is actually growing, for example in San Juan.
The Andes are alive Folguera AndresThe Andes are alive Folguera Andres
Most of the world's mountain ranges are older than the Andes, which border the Pacific Ocean for some 7,500 km.Most of the world's mountain ranges are older than the Andes, which border the Pacific Ocean for some 7,500 km.
"The Andes are alive," says Mr Andres."The Andes are alive," says Mr Andres.
The shifting Andes are a product of subduction.The shifting Andes are a product of subduction.
Subduction zones are areas where one of the Earth's tectonic plates sinks beneath another, generating huge forces.Subduction zones are areas where one of the Earth's tectonic plates sinks beneath another, generating huge forces.
The sites are also where the largest and most destructive earthquakes on the planet occur when there is a sudden release of the stress produced when parts of the two plates stick to each other.The sites are also where the largest and most destructive earthquakes on the planet occur when there is a sudden release of the stress produced when parts of the two plates stick to each other.
Deep underground, the floor of the Pacific Ocean supports the continental shelf on which the Andes rest: but at a strange angle.Deep underground, the floor of the Pacific Ocean supports the continental shelf on which the Andes rest: but at a strange angle.
"The Andes were formed because the bottom of the Pacific Ocean went under the South American continent at an angle of approximately 30 degrees on average," says Mr Andres."The Andes were formed because the bottom of the Pacific Ocean went under the South American continent at an angle of approximately 30 degrees on average," says Mr Andres.
"But there are some places where the ocean floor goes in horizontally, increasing the friction and pushing up the mountain range above, as at the Cordillera Blanca of Peru"."But there are some places where the ocean floor goes in horizontally, increasing the friction and pushing up the mountain range above, as at the Cordillera Blanca of Peru".
But every 5 to 10 million years the ocean floor begins to slide under the continental shelf at an angle causing the mountain range above it to crumble.But every 5 to 10 million years the ocean floor begins to slide under the continental shelf at an angle causing the mountain range above it to crumble.
Disappearing Andes?Disappearing Andes?
In theory the Andes could disappear.In theory the Andes could disappear.
"Before the Andes were formed there were numerous Andean chains that ran along the edge of South America and many of these chains suffered cycles of collapse," says Mr Andres."Before the Andes were formed there were numerous Andean chains that ran along the edge of South America and many of these chains suffered cycles of collapse," says Mr Andres.
Sometimes these mountains collapsed into the sea; a process that 26m years ago led to the formation of the Drake Passage, the stretch of water that separates the American continent and Antarctica.Sometimes these mountains collapsed into the sea; a process that 26m years ago led to the formation of the Drake Passage, the stretch of water that separates the American continent and Antarctica.
In theory, the reverse process could generate the largest mountain in America.In theory, the reverse process could generate the largest mountain in America.
However, Mr Andres says that the process of gravity makes it unlikely that any mountain higher than 8km can be formed.However, Mr Andres says that the process of gravity makes it unlikely that any mountain higher than 8km can be formed.
Whatever happens the results will not be seen for another 20m or 30m years, "by which time man will have evolved into another species," according to the geologist.Whatever happens the results will not be seen for another 20m or 30m years, "by which time man will have evolved into another species," according to the geologist.