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Mount Everest, the highest mountain in the world and part of the Himalayaswas formed by the collision between the Indian and Eurasian tectonic plates, a process that has lasted millions of years. Recent studies suggest that the margins of these plates already showed considerable elevation before the impact. However, Everest continues to grow at a surprising rate, which has led scientists to conclude that the mountain is experiencing accelerated uplift.
Why is the tallest mountain in the world still growing?
A study published in Nature Geoscience revealed the unknown force that would be driving Mount Everest to continue growing. According to GPS data, Everest grows several millimeters each year, much more than expected based on the dynamics of tectonic plates. This anomaly, which elevates Everest about 250 meters above its closest neighborchallenges conventional explanations and raises questions about the geological processes at work in this region.
Researchers from University College London (UCL) revealed that River erosion at a distance of about 75 kilometers from Mount Everest is the main factor driving growth at a rate of 2 millimeters per year. This geological process has occurred over the last 89,000 years.
Causes of the growth of Everest
Isostatic rebound
A part of this geological anomaly can be attributed to the phenomenon of isostatic rebound. This occurs when erosion reduces the mass of the Earth’s crust in a given area, which in turn decreases the force of gravity exerted on the underlying mantle. As a consequence, the mantle exerts an upward force that causes the crust to rise.
“Mount Everest is an extraordinary mountain, full of myths and legends, that continues to grow. “Our research shows that as the nearby river system deepens, the loss of material causes the mountain to rise even higher,” he explains. Adam Smith, PhD student in Earth Sciences at UCL and co-author of the work.
“A significant part of this anomaly can be explained by an uplift force caused by pressure from beneath the Earth’s crust after a nearby river eroded a considerable amount of rock and soil,” the authors note. This phenomenon, known as isostatic rebound, represents a long-lived geological process capable of significantly shaping the Earth’s relief over geological time scales.
In the last 89,000 years, Everest has grown between 15 and 50 meters due to the phenomenon of isostatic rebound.
Erosion of the Arun River
About 89,000 years ago, the upper course of the Arun River, north of Everest, was joined with its lower course due to erosion towards the north. This caused the entire river to be integrated into the Kosi River system. Erosion increased near Everest and formed the Arun Gorge. As the material was removed, the Earth’s crust lost weight, which led, and continues to lead, to the uplift of the land in the area.
The next step in the investigation will be to analyze the gorge and other areas through which the Arun River passed. This will allow the dates of the capture event to be established with greater precision, which can then be compared with the model. What is clear is that, due to the elastic thickness of the Earth’s crust (which varies between 10 and 30 kilometers), The highest peak on the planet could continue to rise as a result of the formation of the river gorge.
Researchers suggest that the unique topography of the Arun River is closely linked to the growth of Everest. The river flows east at high altitude and then turns sharply to the south, with a steep slope. This geographical configuration, typical of an unstable geological system, could be key to understanding the processes that have shaped the region.
This anomaly not only affects Everest, but also nearby peaks. Isostatic rebound lifts them up faster than erosion wears them down, he notes Matthew Fox, geologist at UCL. According to scientists, The growth of Everest shows the dynamic and changing nature of the Earth.
