The Andes Mountains are over 50 million years old, they were created when the South American and Pacific tectonic plates collided. It is a collection of numerous mountain chains which join together in what are called orographic knots.
The formation of the modern Andes began with the events of the Triassic and Jurassic when Pangea begun to break up and several rifts developed. It was during the Cretaceous period that the Andes began to take their present form, by the uplifting, faulting and folding of sedimentary and metamorphic rock of the ancient cratons to the east. The rise of the Andes has not been constant and different regions have had different degrees of tectonic stress, uplift, and weathering.
About 30, species of Vascular plants live in the Andes, vascular plants include the club mosses, horsetails, ferns, gymnosperms including conifers and angiosperms flowering plants. The small tree Cinchona pubescens, a source of quinine which is used to treat malaria, is found widely in the Andes as far south as Bolivia. Other important crops that came from the Andes are tobacco and potatoes.
These trees are called Quenua by locals, Yagual and other names, can be found at altitudes of 4, m 14, ft above sea level. Tomatoes and potatoes, two of the most prevalent food crops in the world, originated from the Andes.
Peru, one of Andes host countries, is home to at least 3, different varieties of potatoes. Coca tea is a popular beverage in the high Andes, thanks to its effectiveness in relieving symptoms of altitude sickness. In the Andes about 3, species of animals can be found, including species of mammals, 1, species of birds, species of reptiles, and species of fishes, and more than species of amphibians.
High mountains are a dreary habitat for wild life, so mammals living there have thick woolly fur. The Andes are one of the greatest sources of mineral wealth in the world. Andean mines account for more than 45 percent of the world's copper production, nearly 30 percent of the silver production, significant amounts of lead, zinc, gold and an array of industrial minerals and chemicals.
Therefore, it is estimated that a third of people living in South America live in the Andes especially in major cities. The Andes run for about 7, kilometres with the highest peak, Mount Aconcagua in Argentina, rising nearly 7, metres above sea level.
An international team of geologists were intrigued by the Andes' geology and have finally solved a mystery that scientists had previously been unable to answer: the mountains were formed only 45 million years ago yet the massive forces that pushed them up have been at work for million years as the Nazca tectonic plate is thrust under the South American continent. We knew when the subduction began, but why did it take nearly million years before the mountain chain started to rise and what was it that caused the chain to bend the way it does in Bolivia?
The researchers say the traditional approach to plate tectonics, of working back from data, resulted in 2D models with strong descriptive but no predictive power.
I developed a three-dimensional, physical model — I used physics to predict the behaviour of tectonic plates — then I applied data tracing the Andes back 60 million years and it matched," Capitanio says. The researcher essentially switched the traditional approach around: instead of being driven by the data and asking why, he took the predictive method of physics and started investigating what would happen to the physical model if he excluded some factors or added others.
He then cross-checked the results with the actual geological data and found that some physical processes explained certain aspects while others produced different results. They concluded that some parts of the Nazca plate were older so had time to cool, become heavier and sink faster into the Earth's mantle, thereby forcing up parts of what was to become the high parts of the Central Andes.
I have shown that the three-dimensional variation in the age of the Nazca plate during subduction is the key to the formation of the modern Andes. The 4,mile-long 7, kilometers Andes — the longest continuous mountain range in the world — didn't form in the way that scientists had long thought.
Previously, geologists held that the Nazca oceanic plate, which lies under the eastern Pacific Ocean, had steadily and continuously subducted slipped under South America, which made the ground rise and eventually create the towering Andes. But after studying the underground remnants of the Nazca oceanic plate, which sit about miles 1, km underground, the researchers learned that the plate did not go through a steady and continuous subduction.
Rather, the Nazca plate was at times torn away from the Andean margin the place where it was subducting , which led to volcanic activity, the researchers said.
The remains of the subducted Nazca plate are far underground, so how did the scientists study them? When tectonic plates move underground — that is, when they creep under Earth's crust and enter the mantle — they sink toward the core, much like fallen leaves sinking to the bottom of a lake. But these sinking plates retain some of their shape, offering clues to what the Earth's surface looked like millions of years ago.
In the case of the Nazca plate, more than 3, miles 5, km of lithosphere , the outer, rigid part of the crust and upper mantle, was lost to the mantle, the researchers said.
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