It is rightly called “the roof of the world”. The Tibetan Plateau rises more than 4.8 kilometers above sea level and is surrounded by majestic mountain ranges that are home to the two highest peaks in the world, Everest and K2.
As climbers attempt to conquer these majestic peaks, the isolated region is home to many cultures, from Pakistani villages practicing various forms of Islam to Buddhist communities in Tibet.
Perhaps the most famous person in the area is the Dalai Lama, the spiritual leader of Tibet and a proponent of the search for independence for this space, according to Live Science.
The story of the “roof of the world”
Less well known is the story of the formation of the Tibetan Plateau and the surrounding rocky mountains. The geological story, as it is known, is familiar to many schoolchildren: 50 million years ago, the Indian subcontinent entered a collision course with Eurasia, causing the formation of a larger strip of land, and then the plateau, Himalayas and Karakorum regions were born.
But the story does not end here. “It’s a complex place,” said Lee Royden of the Massachusetts Institute of Technology and author of a study published in the journal Science. Before India collided with Eurasia, the ocean of Tethys, which separates the two regions, was laid under Eurasia. In the late Cretaceous period – about 100-65 million years ago – volcanic mountains similar to the modern Andes appeared on the southern edge of the Eurasian plateau.
But these early mountains would not have been at all like what we mean by mountains today, nor with the ones that exist today. Experts say that those early tectonic movements would have raised certain parts of the plateau above sea level, causing the continental crust to thin, preparing the land for what came next.
After the collision, more of the area now included in the plateau underwent changes due to tectonic movements, with southern and central parts of Tibet rising to higher elevations as the crust changed. With pressure on the crust, the peaks that make up the Himalayas or Karakorum today rose higher and higher, to the heights we can see.
As the collision progressed, lithospheric material above the crust’s surface was pushed eastward, Royden says. These parts of the lithosphere were supported by the eastward movement of the Pacific subduction trenches to the east, where China is today.
20 million years ago, the trenches stopped moving east. As the collision between India and Eurasia continues, “things can’t go east,” Royden says. Although most experts say that crustal shortening shaped the eastern plateau, Royden is of the view that this is not a necessarily valid theory, because there is not much evidence in this regard.
The movement of the lithosphere under the plateau may have caused the Sichuan earthquake. The area where the earthquake occurred has traditionally been considered an area of low risk of tectonic movements. Some geologists believe that the tectonic movement was the result of a sliver of thrust on top of each other. But “when you look at the whole geological context,” Royden says, “it could be the reason for the vertical rise of the lithosphere in the area.”
As the materials are pushed to the east and collide with each other, the more solid parts of the Sichuan Basin region pile up on the eastern side. Royden’s explanation is that the vertical fault and movement from the east caused the earthquake. Although many aspects of this plateau remain mysterious, Royden believes that within a decade or two, geologists will have a clearer picture of what is going on under the “world’s roof.”
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