Thanks to the development of a new method, researchers at the University of Copenhagen may be able to answer several unanswered geological questions and learn more about the great mysteries of our planet and its evolution. Before they got there, they first focused on the geological development of the longest mountain range in the world: the Andes. Using this new method of geological research, they were able to determine how this huge mountain range was formed…
In fact, using a new method developed by a researcher from the University of Copenhagen, the team began to study the tectonic plate on which the Andes Mountains lie. They then discovered new elements that explain how this colossal mountain range could have formed from the earth’s interior. The results of the study are published in the journal Earth and Planetary Science Letters.
The Andes – the longest continental mountain range in the world – stretch over 8,900 kilometers on the western edge of South America and are up to 700 kilometers wide. It crosses a total of seven countries, starting in Venezuela, passing through Colombia, Ecuador, Peru, Bolivia and ending in Patagonia, southern Chile and Argentina.
The tectonic plates that cover the Earth’s surface move a few centimeters each year (about as fast as our fingernails grow). These plates can sometimes speed up or slow down suddenly. With their new method, the researchers were able to obtain more accurate estimates of the extent and frequency of disk speed changes in the past.
The lithosphere, the outermost moving layer of the Earth, is divided into a small number of rigid moving plates on top of the asthenosphere, the part of the Earth’s mantle just below. This structuring controls geological phenomena such as earthquakes or volcanism. It also influences the climate of our planet (particularly via the mountain ranges and the long carbon cycle) and has played an essential role in the origin and evolution of life (changing the atmosphere, formation and displacement of continents).
This is shown by the new calculations of the researchers, who are taking a close look at the case of the Andes Cordillera the South American plate has changed gears suddenly and dramatically in the past 15 million years, slowing down significantly on two occasions. This slowdown may then have contributed to the widening of this vast mountain range.
“In the periods preceding the two downturns, the plate immediately to the west, the Nazca Plate, pushed and compressed the mountains, causing them to grow.” This result may indicate that some of the pre-existing range on both the Nazca Plate and acted as a brake on the South American plate. Instead, as the plates slowed, the mountains widened,” says Valentina Espinoza, lead author and PhD student in the Department of Geosciences and Natural Resource Management.
How can the slowing of the South American plate be explained?
3D rendering of South America with the Andes
© Saylowe / Pixabay – License: Pixabay
According to the results of the study, the South American plate slowed down by 13% in one period 10 to 14 million years ago and by 20% in another period 5 to 9 million years ago. On the geological time scale, these changes are very rapid and abrupt.
There would be two main reasons for these sudden slowdowns. On the one hand, the researchers propose the hypothesis that the interaction between the expansion of the mountains and the slower speed of the plates is due to a phenomenon called delamination. This means that much of the unstable material beneath the Andes broke off and sank into the Earth’s mantle, causing major plate configuration readjustments.
So, according to this assumption: The Andes changed shape and grew laterally. During this time, the mountains stretched as far as Chile to the west and Argentina to the east. The more rock material accumulated on the plate and the heavier it became, the slower its movement became.
“If this explanation is correct, it tells us a lot about how this huge mountain range was formed. But there is still a lot we don’t know. Why did it get so big? How fast did it form? How does the mountain come about?” Does the range hold together? And will it eventually collapse?” asks Valentina Espinoza.
On the other hand, the researchers put forward a second possible hypothesis that could be causing the disk to slow down a change in the flow of heat from the Earth’s interior – known as convection – moving in the highest viscous layer of the Earth’s mantle, on which tectonic plates float.
A new standard method?
This new method of calculating changes in tectonic plate motion provides estimates with unprecedented accuracy. she uses high-resolution geological data, is generally used to calculate the motion of plates relative to each other. However, this new method uses the same data to calculate changes in plate motion relative to the planet itself.
The research team believes it could become a standard method. “This method is applicable to all plates as long as high-resolution data is available. I hope that with such a method, historical models of tectonic plates will be refined, thus improving the chances of reconstructing geological phenomena that are still unclear to us.” of the plates that took place over time, we may have a chance to solve some of the greatest mysteries of our planet and its evolution.” . We still know so little about, for example, the temperature in the Earth’s interior or roughly when the plates began to move. Our method can most likely be used to find pieces for this big puzzle.”
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