Mount Everest grows faster than expected – 01/10/2024 – Science

The tallest mountain on Earth, at 8.85 kilometers above sea level, Mount Everest is still growing.

Although the mountain and the rest of the Himalayas have seen a relentless rise dating back to their emergence about 50 million years ago, when the Indian subcontinent collided with Eurasia, Everest is growing larger than expected. This, according to scientists, is associated with the merging of two river systems.

Mount Everest gained approximately 15 to 50 meters in height due to a change in the regional river system, with the Kosi River merging with the Arun River 89,000 years ago, researchers estimate. This translates to a rate of rise of 0.2 to 0.5 mm per year.

The geological process at work, according to the researchers, is called isostatic rebound. It involves the lifting of land masses in the Earth’s crust when the weight of the surface decreases. The crust, the Earth’s outer layer, essentially floats above the mantle made up of hot, semi-liquid rock.

In this case, the merger of the two rivers—more like a hostile takeover, with the Kosi overtaking the Arun as the course of the rivers changed over time—led to accelerated erosion that washed away large amounts of rock and soil, nearly reducing the weight of the area to Everest.

“Balanced rebound can be compared to a floating object that adjusts its position when a weight is removed,” said geologist Jin Jindai of the China University of Geosciences in Beijing, one of the leaders of the research team. He studies Published on Monday (30) in the magazine Natural Earth Sciences.

“When a heavy load, such as ice or eroded rock, is removed from the Earth’s crust, the ground beneath it slowly rises in response, much like a boat rising in the water when the load is unloaded,” Day said.

The main gorge of the combined river system is located about 45 km east of Everest.

The researchers used numerical models to simulate the evolution of the river system. They calculate that the bounce represents about 10% of Everest’s annual ascent.

This geological process is not limited to the Himalayas.

“A classic example is Scandinavia, where land is still rising in response to the melting of thick sheets of ice that covered the region during the last ice age. This process continues today, affecting coastlines and landscapes, thousands of years after the ice retreated,” Day said. .

GPS measurements show the continued rise of Mount Everest and the rest of the Himalayas, said study co-author Adam Smith, a PhD student in geosciences at University College London.

This survey overcomes continuous surface erosion caused by factors such as wind, rain and river flow. As this erosion continues, the rate of Mount Everest’s ascent from isostatic rebound could increase, Smith said.

Neighboring peaks, including Lhotse, the fourth-highest mountain in the world, and Makalu, the fifth-highest, also receive a boost from the same process. Lhotse is experiencing a similar rate of ascent to Everest. Makalu, closest to Aaron, has a slightly higher rate of rise.

“This research highlights the dynamic nature of our planet. Even seemingly immutable landmarks like Mount Everest are subject to ongoing geological processes, reminding us that the Earth is constantly changing, often in ways imperceptible in our daily lives,” Day said.

The solid outer part of the Earth is divided into enormous plates that gradually move over time in a process called plate tectonics, where the Himalayas rise after a collision between two plates.

Mount Everest is located on the border between Nepal and Tibet. It is named after the British surveyor George Everest (1790-1866).

“Mount Everest occupies a unique place in human consciousness,” Day said. “Physically, it represents the highest point on Earth, giving it enormous significance simply because of its stature. Culturally, it is sacred to the local Sherpa and Tibetan communities. Globally, it symbolizes the ultimate challenge, embodying human endurance and our willingness to overcome.” On this point.