Mount Everest's Growth Largely Due to Nearby River Systems Merging Hundreds of Centuries Ago
The Himalayan Mount Everest, with an impressive height reaching 29,032 feet above sea level, overshadows its neighboring peaks by a couple hundred feet. Intriguingly, according to scientists, this tallest peak in the world is still growing. A contributing factor to this growth appears to be the union of two adjacent river systems that happened tens of thousands of years ago.
The study, published in the Nature Geosciences journal on Monday, elucidates the fact that 50 to 160 feet of Everest's contemporary height is linked to the rivers' merger. Recent years have seen this annual expansion rate quicken to fractions of a millimeter. "Even a feature as seemingly permanent as Mount Everest is subject to ongoing changes driven by various geological forces," shared Dai Jingen, a co-author of the study and a geoscientist at China University of Geosciences in Beijing.
Ever since its birthing about 45 million years ago due to the clash of tectonic plates beneath the Indian subcontinent and Eurasia, Mount Everest, has been consistently increasing in height, just like the rest of the Himalayas. However, the precise rate at which Everest was growing remained to be fully elucidated.
It is now believed that approximately 89,000 years ago, when the Kosi River merged with the Arun River, it birthed a river of such colossal power that it eroded massive amounts of rock and soil from the base of the Himalayas nearly 50 miles away from Everest. This erosion and resultant movement in the Earth's crust by a process known as isostatic rebound made a significant contribution to the mountain’s elevation, and although it was indirect, the river definitely played a role in increasing Everest's height.
According to estimates, the isostatic rebound effect causes Everest to grow between 0.16 to 0.53 millimeters a year, accounting for up to half of its total annual uplift rate. In recent years, Everest has been found to be growing by up to 2 millimeters per year. This phenomenon might explain why Everest stands unusually taller, by almost 800 feet, compared to its adjacent peaks.
Dai mentioned that the discovery of river capture and isostatic rebound due to erosion having an influence on Everest's elevation adds a remarkable insight to the study of mountain formation, an area usually attributed only to tectonic activity. The finding could potentially lead to a re-examination of the current models of Himalayan formation and evolution. "These findings are undeniably surprising," stated Dai, further underlining that this emphasizes the need to view the Earth as an interconnected system where changes in one area can cause surprising and significant effects in another.