Scientists discover the anomaly that causes Everest to grow larger than the other eight-thousanders

BarcelonaThe Earth's roof is rising by two millimeters every year. Mount Everest, the tallest mountain on Earth, has grown between 15 and 50 meters in the last 89,000 years, much more than the other eight-thousanders that make up the Himalayas. This is a geological anomalySince the altitudes of mountains in the same mountain range should be similar, researchers from University College London and the China University of Geosciences may have solved this problem. In a study published in the journal Nature Geoscience They have shown that erosion of the Arun Gorge, a river near Everest, is pushing the mountain's summit upward. The summit already measures 8,849 meters (28,500 feet) high, some 250 meters (860 feet) above the next highest peak, K2. According to the researchers, the Arun has carved a significant gorge over millennia, carrying billions of tons of soil and sediment from the base of Everest. This has caused the pressure exerted on the mountain from beneath the Earth's crust, as a result of this constant erosion, to be greater than the force of gravity. This is a phenomenon called isostatic reboundThis occurs when the crust loses too much material and deforms, and the liquid mantle inside the Earth sends great pressure upwards. This would explain why Everest is noticeably taller than the other eight-thousanders in the Himalayas.

It is a gradual process, about two millimeters per year, which researchers have demonstrated using GPS instruments. Thus, as the Arun river system deepens, the loss of material is causing the mountain to grow more. The uplift is not limited to Everest, but also affects its neighbors Lhotse and Makalu, the fourth and fifth highest peaks in the world, respectively. Makalu, moreover, is closer to the river and its uplift rate is slightly higher.

River Merging

The Arun is one of the main tributaries of another Nepalese river, the Kosi. Scientists used numerical models to simulate the evolution of the Kosi River network and compare it with the existing topography, that is, the current land surface. These models suggest that the Arun merged with another river 89,000 years ago and captured its drainage network. The diversion of water as the river adapted to the new course led to the creation of the deep Arun Gorge. During the formation of this gorge, there was a sudden retreat of sediment which, according to the authors, would have contributed to the uplift of the surface.