Isostatic Rebound
Kartavya Desk Staff
Source: IE
Context: A recent study suggests that Mount Everest has grown 15-50 meters taller than expected over 89,000 years due to the erosion caused by the Arun River, which helps push the peak upwards by up to 2mm annually.
More about study:
• Isostatic Rebound: The reduction of landmass in the Arun River basin leads to isostatic rebound, where the Earth’s crust rises due to diminished surface weight, akin to a floating object adjusting when weight is removed.
• Impact on Neighboring Peaks: The isostatic rebound affects other Himalayan peaks like Lhotse and Makalu, contributing to their elevation increase.
• Himalayan Uplift: Everest has been rising due to the collision of the Indian and Eurasian plates for 50 million years. The Arun River’s erosion adds an extra boost to this process.
About Isostatic rebound:
Isostatic Rebound:
Isostatic rebound, also called post-glacial rebound or glacial isostasy, is the gradual rise of Earth’s crust after the removal of heavy weight, such as ice sheets or eroded landmasses.
• This phenomenon occurs due to the Earth’s lithosphere (crust and upper mantle) behaving elastically over time.
• When heavy loads, like glaciers, depress the Earth’s surface, their melting or erosion leads to the land rebounding or rising as the weight is removed.
• This process takes thousands of years and continues even after the glaciers have disappeared.
Process and Importance:
• Force: The Earth’s crust behaves much like a floating object in a fluid. When a heavy load like an ice sheet or eroded rock is removed, the crust “rebounds” upward in response to the decrease in pressure.
• Geography: Isostatic rebound is particularly significant in areas once covered by massive ice sheets, like Scandinavia and Canada. The process can also occur due to erosion in mountainous regions, as in the case of Mount Everest.
• Importance: It helps maintain the height of mountains and other elevated landforms, compensating for erosion by lifting the land. It also influences sea levels and can impact tectonic activity in certain regions.
Arun River:
• Origin: The Arun River originates from the Tibet Autonomous Region of China.
• Flow: It flows through Tibet and Nepal before joining the Saptakoshi River in Nepal, which later merges with the Ganges in India.
• Tributaries: The Barun River and the Sankhuwa River in Nepal.
• India: Although the Arun River does not directly flow through India, it indirectly influences the flow of rivers that contribute to the Ganges Basin in northern India
Insta Links:
• Isostacy