Ancient lake outburst 'holds clues to climate change events'
23 June 2011 | EN
Unique lake burst records indicates Indus river vulnerable to climate change
Flickr-mckaysavage
A team of Indian geologists from the University of Pune and the Wadia Institute of Himalayan Geology, Dehradun, has been studying the site of the ancient outburst in a deep gorge close to the exit of the Indus river in the Spituk-Leh valley.
The valley suffered an unprecedented cloud burst on last year (6 August) causing flash floods that devastated large areas and killed 180 people.
Sliding and slumping of rocks and lake beds, compounded by climate change can result in the formation of steep valleys, lake bursts and 'damming' or containment of water within narrow gorges.
Unlike other sediment records in the area, which have eroded, the study site on the outskirts of Leh is well preserved and displays sediment from the flooding of the Indus river in the Pleistocene age, at least 20,000 years ago.
The team reported this month (10 June) in Current Science that the present record of an entire lake burst at a height of 3,245 metres in Leh "is a witness to the susceptibility of the Indus river to damming (and outburst) due to distinctive geomorphic (earth) changes available at the present outlet of the Spituk-Leh valley".
Glacial recession, the possibility of new lake basins being created by glacial melt and the damming of rivers followed by lake outbursts and related flash floods are likely to increase, they said.
"The studied past record proves that the geomorphic setup (for lake outbursts) is available in the Leh valley for such a thing to happen when climate change of that dimension (most probably during late Pleistocene-Holocene times or around 10,000 years back) occurs (again)," lead scientist Satish Sangode told SciDev.Net.
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