Evidence of Himalayan Rockslide Found, May Have Knocked Off One of Highest Peaks

Evidence of a giant rockslide in one of the Himalaya’s highest mountain peaks during the Middle Ages has been unearthed, an event that could have possibly knocked several hundred metres off the height of the summit, scientists say. Jerome Lave from the Universite de Lorraine, France, and colleagues have found geological evidence for an abrupt, high-altitude rockslide that may have occurred around 1190 AD in the Annapurna mountain range of the Himalayas, in central Nepal, that could help understand Himalayan evolution better.

The sudden collapse involving a total rock volume of around 23 cubic kilometres may have brought down the peak by several hundred metres and prevented the disproportionate growth of the Himalayan peaks, the scientists said in a paper published in the journal Nature.

They suggested the presence of permafrost at high altitude to be behind the giant rockslide.

Having massive implications for landscape evolution and natural hazards, they said, massive supplies of finely crushed sediments could have filled valleys more than 150 km downstream and overwhelm Himalayan rivers for more than a century.

Despite previous numerous studies on Himalayan erosion, the authors wrote, little is known about how the peaks of the Earth’s tallest and one of the most active mountain ranges erode and evolve. The shape and altitude of mountain peaks are constantly evolving in response to tectonic plate movements and erosion.

They said that the findings shed light on one potential mode of evolution of high Himalayan peaks and their abrupt erosion by large rockslides.

They called for future studies to assess the erosive contribution of giant rockslides on the long-term topographic evolution of these mountain ranges.