ARUN RIVER

• A recent study suggests that over the past 89,000 years, it has grown 15 to 50 meters higher than anticipated.

The Arun River is contributing to the rise of Mount Everest through a process called isostatic rebound. Here’s how it works:

River Incision:

• The Arun River, which flows about 75 km from Mount Everest, is eroding large amounts of rock and soil from the surrounding landscape.
• This process of erosion reduces the weight on the Earth’s crust in the Arun River basin.
• A study by UCL suggests that the Arun River’s ability to carve out large amounts of rock and other materials may be due to it capturing another river or water system in Tibet.
• This process is known as River Incision, where the river cuts downward into its bed, deepening its channel.
• The erosion began to accelerate around 89,000 years ago when the Arun River merged with the Kosi River, removing large amounts of landmass and further reducing the weight on the region’s crust.

Isostatic Rebound:

• When the weight of the land (due to rocks, soil, or even ice) decreases, the Earth’s crust rises to balance the change.
• This is similar to how a boat rises in water when heavy cargo is removed.
• The removal of landmass in the Arun River basin allows the crust underneath Mount Everest to rise.