Recent geological research suggests that Everest’s extreme height may be due in part to ancient fluvial activity that played an important role in shaping the Himalayan landscape.

Role of ancient rivers in shaping Everest’s height

New research published in the journal Natural Geologysuggests that two ancient rivers that once flowed through the Himalayas may have influenced the height of Everest. About 89,000 years ago, these rivers joined, causing extensive erosion and transporting large amounts of rock and soil from around the mountain.

This led to a phenomenon called “isostatic rebound,” in which the Earth’s crust responds to the loss of mass by rising upward.

This recovery could eventually lift Everest by as much as 50 metres, according to Matt Fox, a geologist at University College London and co-author of the study.

The formation of the Himalayas and the growth of Everest

The Himalayas, including Mount Everest, were formed as a result of the collision of the Indian subcontinent with the rest of Asia, a process that continues to this day. This tectonic activity causes the area to rise and the mountains to rise even higher.

Everest, known locally as Jomolungma and Sagarmatha, benefits from this tectonic force, but the study shows that ancient rivers played a crucial role in Everest’s extraordinary height.

Impact of the Arun River

Researchers point to the Arun River, a dramatic gorge that cuts through the mountains near Everest, as a key player in this process. Arun originates in the north of the Himalayas, then turns south and joins the Kosi River, heading towards the highest mountain ranges on Earth.

For decades, scientists have debated whether Arun existed before the Himalayas were formed or whether it appeared later. Fox and his colleagues argue that Arun probably passed through the mountains during the river invasion, when one river diverted another.

This dramatic event, possibly caused by a flood, increased erosion along the Arun Road and significantly changed the landscape.

Consequences of erosion: increasing the height of Everest

After the capture of the river, the Arun rapidly eroded the surrounding area and washed away large amounts of sedimentary rock. This reduction in mass caused the Earth’s crust to rise in a process known as isostatic rebound. Fox and his team estimate that this process added 15 to 50 meters to Everest’s height over thousands of years.

Although tectonic uplift was the main driver of Himalayan growth, this additional uplift highlights the significant influence of ancient rivers.

Scientists have no common solution

Although the study offers a compelling explanation, some geologists remain skeptical. Geologist Pieter van der Beek of the University of Potsdam says the timing of the river’s capture remains unclear because the study is based on simplified models of river behavior.

He also notes that long-term estimates of tectonic uplift and erosion are difficult to determine due to limited historical data.

Additionally, major seismic events such as the 2015 Nepal earthquake, which caused Himalayan peaks to collapse by nearly 1 meter, can significantly impact mountain heights over time.

Although Everest’s height is determined primarily by tectonic forces, this new study adds another fascinating aspect to the story of the peak’s formation. The influence of ancient rivers such as the Arun, combined with tectonic collisions that continue to this day, helped make Everest the highest mountain on Earth, and future research may continue to uncover new factors that shaped this iconic peak.