Andes Grew to Towering Heights in Two Explosive 'Growth Spurts'

The Cuernos del Paine in Chile belong to the Andes Range of mountains.

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Far from a procedure of smooth, inescapable ascendance, the development of the renowned Andes Mountains was downright explosive. As the peaks increased skyward along the western coast of South America lots of countless years earlier, violent volcanic activity rocked the continent, a brand-new research study discovers.

Scientists made the discovery by studying the buried residues of the continent’s tectonic plates. And what the researchers discovered stunned them.

The 4,300- mile-long (7,000 kilometers) Andes– the longest constant range of mountains on the planet– didn’t form in the manner in which researchers had long idea. Formerly, geologists held that the Nazca oceanic plate, which lies under the eastern Pacific Ocean, had progressively and constantly subducted (slipped under) South America, that made the ground increase and ultimately develop the towering Andes. [Photos: The World’s Tallest Mountains]

” The Andes Mountain development has actually long been a paradigm of plate tectonics,” research study co-author Jonny Wu, assistant teacher of geology at the University of Houston, stated in a declaration

However after studying the underground residues of the Nazca oceanic plate, which sit about 900 miles (1,500 km) underground, the scientists found out that the plate did not go through a consistent and constant subduction. Rather, the Nazca plate was at times torn far from the Andean margin (the location where it was subducting), which resulted in volcanic activity, the scientists stated.

To verify their work, the researchers designed volcanic activity along this margin.

” We had the ability to evaluate this design by taking a look at the pattern of over 14,000 volcanic records along the Andes,” a few of which go back to the Cretaceous, Wu stated.

The remains of the subducted Nazca plate are far underground, so how did the researchers study them?

When tectonic plates move underground– that is, when they sneak under Earth’s crust and get in the mantle– they sink towards the core, just like fallen leaves sinking to the bottom of a lake. However these sinking plates maintain a few of their shape, providing ideas to what the Earth’s surface area appeared like countless years earlier. When it comes to the Nazca plate, more than 3,400 miles (5,500 km) of lithosphere, the external, stiff part of the crust and upper mantle, was lost to the mantle, the scientists stated.

Researchers can image these plates utilizing information gathered from earthquake waves, just like a computed tomography (CT) scan enables physicians to see the within a client.

” We have actually tried to return in time with more precision than anybody has actually ever done prior to. This has actually led to more information than formerly believed possible,” Wu stated. “We have actually handled to return to the age of the dinosaurs.”

When it comes to this research study, after examining these underground tectonic leftovers, the scientists had the ability to piece together how the Andes formed. The subducting Nazca plate knocked into a shift zone, or an alternate layer in the mantle, which slowed the plate’s motion and triggered accumulation above it, the scientists stated in the declaration.

Their design recommends that the currents stage of the Nazca subduction started in what is now Peru, throughout the late Cretaceous duration, about 80 million years earlier, the scientists composed in the research study. Then, the subduction moved southward, reaching the southern Andes in Chile by the early Cenozoic, about 55 million years earlier, they stated.

” Hence, contrary to the existing paradigm, Nazca subduction has actually not been completely constant because the Mesozoic however rather consisted of episodic divergent stages,” the scientists composed in the research study.

The research study was released online today (Jan. 23) in the journal Nature

Initially released on Live Science