Himalayas are the highest mountain range in the world
We walked all this time all mistaken. The geology that sustains Himalayas may not be what we thought. A theory At 100 years old that explains how Asia can withstand the huge weight of Himalayas and Tibetan plateau is about to crumble.
The mountains of Himalay They formed the collision between the Asian and Indian continents about 50 million years ago, when tectonic forces compressed Tibet in such a way that the region wrinkled and its area shrunk almost 1,000 kilometers.
The Indian tectonic plate eventually slipped under the eurasian plate, doubling the thickness of the earth’s crust under the Himalayas and the Tibetan Plateau to the north, and contributing to its survey.
For a century, the dominant theory was that this duplication of the crust alone supported the weight of Himalayas and the Tibetan Plateau. A study in 1924 by Swiss geologist Émile Argand shows the Indian and Asian crusts stacked on each other, extending together 70 to 80 kilometers (45 to 50 miles) deep under the earth’s surface.
However, a study last week in the magazine Tectonics call into question this theory.
After all, the rocks of the crust will have become cast at about 40 kilometers deep due to extreme temperatures.
“If you have 70 km of crust, then the lower part becomes ductile… it is like yogurt-and You can’t build a mountain on top of yogurt”, explicou, a Live Science, Pietro SternaiAssociate Professor of Geophysics at the University of Milano-Bicocca (Italy) and the main author of the new study.
Evidence has long suggested that Argand’s theory is erroneous, but the idea of two crusts aroused stacked is so appealing that most geologists did not question it, Sternai said.
The new study reveals that there is a portion of interspersed cloak between Asian and Indian crusts. “This explains why the Himalayas have grown so much, and how they are still so high today,” the authors wrote in the article.
The new model showed that as the Indian plate slipped under the eurasian plate and began to liquefy, fragments of it climbed and fixed not at the bottom of the Asian crust, but at the base of the lithosphere, which is the outer rigid layer of the planet composed by the crust and the upper cloak.
This is fundamental, said Sternai, “because it means that there is a rigid layer of cloak between the stacked crusts that solidifies the entire structure under the Himalayas.”
Both crusts float enough to keep the region upwhile the cloak material provides resistance and mechanical strength. “You have all the ingredients you need to raise the topography and support the weight of the Himalayas and the Tibetan Plateau,” he said.
“The” sandwich “of the mantle in the simulation corresponded to previous evidence that Argand’s theory could not explain,” said the study co-author Simone PiliaAssistant Professor of Geosciences at the University of King Fahd of Petroleum and Minerals in Saudi Arabia, also to Live Science.
“Things begin to make sense now. Observations that seemed enigmatic are now more easily explained with a model where you have crust, cloak, crust, ”he added.
Douwe van HinsbergenProfessor of Global Tectonics and Paleogeography at the University of Utrecht, in the Netherlands, points out that this is a great discovery.
“If a continent pushes under another continent, a sandwich would be expected from top to bottom, on the upper plate crust and lithosphere (tibet), and then in the lower plate crust (India),” he told Live Science. But that’s not what happened. It seems that we were betrayed by the geology of the Himalayas.
