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With climate change aggravating the melting of glaciers across the world, scientists have for the first time spotted a rare event in the Himalayan glaciers. It has abruptly changed its main course and scientists are attributing it to climate change and tectonic movements.

Indian researchers were studying an unnamed glacier in the upper Kali Ganga valley of Uttarakhand’s Pithoragarh district when they noticed that the glacier had abruptly changed its usual course due to an accumulated influence of both climate and tectonics. Researchers believe that the abnormal behaviour of the glacier suggests that not only is climate a controlling factor, but tectonics also plays an important role in glacial catchments.

The change in the glacier’s movement further confirms the findings behind the February 7 disaster in the hilly terrain of Chamoli in which over 200 people were killed. Scientists have said that the tragedy began on top of the six km-high Ronti peak, where a large mass of ice and rock dislodged from the slopes, triggering a massive landslide that transformed into mud and debris flow, causing destruction along its path.

The debris flow generated a powerful air blast that flattened nearly 20 hectares of forests.

The incident showed how rock mass on which the glacier was sitting gradually became fragile due to weathering, percolation of meltwater in joints, crevasses, freezing and thawing, snowfall, overloading, and gradually operating tectonic forces leading rocks to mechanical disintegration with due course of time and detached from the source rock.

The new findings suggest that the Himalayas is an active mountain range and highly fragile where tectonics and climate play a critical role. The new study conducted by a team of scientists from Wadia Institute of Himalayan Geology (WIHG), Dehradun has been published in ‘Geoscience Journal’.

Scientists reported that the five-kilometre-long unnamed glacier, which covered four square kilometre area in Kuthi Yankti valley (a tributary of Kali river) had abruptly changed its main course. The northeast moving glacier has been truncated and forced to move towards the southeast and ultimately merge with the adjacent glacier named Sumzurkchanki as a result of tectonic forcing.

“The study will help in understanding the glacial-tectonic interaction and provides key information for future studies,” the paper said.

Researchers used satellite images, toposheet and Google Earth images to assess that the glacier had been affected by active fault and climate change as an active fault produced a fault scarp that measures about 250 m in height with a northerly dip is 6.2 kilometres in length and trends towards NW-SE.

“It is one of the unique behaviours of the glacier, and no such observation has so far been reported on this type of glacier kinematics. The study indicates that climate is not the only factor that triggers disasters in the Himalaya, which is an active mountain range, but tectonics also plays an important role in glacial catchments,” Ministry of Science & Technology said in a release.

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India today

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