According to a new study featured in the journal ‘Nature Geoscience’, Mount Everest, which stands tall at a height of 8.85 km above sea level, is continuing to grow in elevation.
Following the collision of the Indian subcontinent with Eurasia approximately 50 million years ago, the Himalayas, encompassing Mount Everest, have begun to experience a steady elevation. Nevertheless, relying entirely on this historical growth, Everest's rise is surpassing expectations. According to researchers, the height gained by the mountain is connected to the substantial amalgamation of the two nearby river systems.
As per their calculations, the change in this regional river system has played a role in the elevation of Everest by roughly 49 to 164 feet (15 to 50 meters). This unification happened around 89.000 years ago, when the Kosi River merged with the Arun River. This alterations caused an uplift rate of around 0.01 to 0.02 inches (0.2 to 0.5 millimeters) perennially.
The science behind this phenomenon is termed isostatic rebound: the ascending movement of the land masses on the Earth's crust when surface weight drops. Basically, the Earth's outer layer, also known as the crust, floats on a mantle comprising hot, semi-liquid rock.
In this case, the amalgamation of the two rivers- to be more precise, the forceful takeover with the Kosi controlling the Arun River as their courses shifted- has caused extended erosion, which in turn has led to the erasing of a considerable amount of rock and soil, bringing down the weight of the area around Mount Everest.
The research, which was published on Monday in the journal ‘Nature Geoscience', was co-led by Geoscientist Jin-GennDainfrom China University of Geosciences in Beijing. He explained, “Isostatic rebound can be compared to a floating object adjusting when weight is lifted.” He further elaborated, “When a heavy load, such as ice or eroded materials, is removed from the Earth's crust, the land beneath gradually rises in response, similar to how a boat rises in water when its cargo is offloaded.”
Around 28 miles (45 kilometers) east of Everest, lies the primary gorge of the newly unified river systems.
By using numerical models to imitate the development of the river systems, the researchers have discovered that isostatic rebound contributes nearly 10% to Everest's perennial uplift rate.
Scandinavia
Did you know, this geological phenomenon is not unique to the Himalayas solely? As Dai explained, “A well-known instance is found in Scandinavia, where the land continues to rise as a result of the melting ice sheets that once covered the area during the last Ice Age. This ongoing process is reshaping coastlines and landscapes thousands of years after the ice has retreated.”
GPS data signals the continuing rise of Everest and the surrounding Himalayas, notes Adam Smith, the co-author of the new study and a doctoral student in Earth Sciences at University College London.
This elevation surpasses the impact of the ongoing erosion of the surface caused by river flow, wind and rain. Smith further explained that if the erosion continues, the rate at which Everest is growing due to isostatic rebound, could increase.
This geological process proves advantageous for peaks in vicinity, like the fourth highest mountain in the world- Lhotse, and the fifth highest- Makalu. Lhotse goes through nearly the same uplift rate as Everest, whereas, Makalu, which is located nearer to the Arun River, experiences a slightly higher rate of increase in elevation.
Dai remarked, “This research highlights the dynamic nature of our planet. Even a seemingly unchanging feature like Mount Everest is influenced by continuous geological processes, reminding us that Earth is in a constant state of flux, often in ways that go unnoticed in our daily lives.”
The Earth's stiff outer layer is composed of huge plates that shift eventually over time in a phenomenon known as plate tectonics. As a result of the collision between two of these plates, the Himalayas have risen.
Mount Everest, referred to as Sagarmatha in Nepali and Chomolungma in Tibetan, is located on the border of Nepal and the Tibet Autonomous Region of China. The name was coined after George Everest, who was a British surveyor working in India during the 19th century.
"Mount Everest holds a distinctive place in human awareness," Dai noted.
"Geographically, it represents the highest point on Earth, giving it great significance due to its height," Dai continued. "Culturally, Everest is revered by the local Sherpa and Tibetan communities. On a global scale, it symbolizes the ultimate challenge, representing human resilience and our ambition to transcend perceived limitations."
