Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Historic Himalayan ice dams created huge lakes, mammoth floods

14.12.2004


Ice dams across the deepest gorge on Earth created some of the highest-elevation lakes in history. New research shows the most recent of these lakes, in the Himalaya Mountains of Tibet, broke through its ice barrier somewhere between 600 and 900 AD, causing massive torrents of water to pour through the Himalayas into India.



Geological evidence points to the existence of at least three lakes, and probably four, at various times in history when glacial ice from the Himalayas blocked the flow of the Tsangpo River in Tibet, said University of Washington geologist David Montgomery, a professor of Earth and space sciences.

Carbon dating shows the most recent lake, about 780 feet deep, burst through the ice dam between 1,100 and 1,400 years ago, rapidly draining some 50 cubic miles of water. The second lake, more than 2,200 feet deep, dates from about 10,000 years ago, and likely held more than 500 cubic miles of water. When that ice dam broke, it caused one of the greatest floods on Earth since the last ice age. The Tsangpo is the world’s highest river, with an average elevation of 13,000 feet, about 500 feet higher than South America’s Lake Titicaca, the highest lake. The Tsangpo flows to the eastern edge of Tibet before it turns south and plunges through a deep gorge into India, where it eventually becomes the Brahmaputra River and flows into the Bay of Bengal.


The new evidence indicates that several times in the Tsangpo’s history, moisture from strengthening monsoons built Himalayan glaciers into huge ice dams, stopping the river before it could leave Tibet. A group of researchers led by Montgomery found evidence of the resulting lakes in ledges carved into the sides of the Tsangpo gorge.

"It is possible that there would have been water close to the crest of the Himalayas," Montgomery said. "Not the high peaks but the passes, and they were probably blocked by ice too. It probably was like an ice-dammed ocean up there."

The group will present evidence of repeated damming and flooding of the Tsangpo gorge on Wednesday at the American Geophysical Union fall meeting in San Francisco. Co-presenters are Bernard Hallet, Alan Gillespie, Noah Finnegan, Matthew Kuharic, Amanda Henck, Alison Anders and Harvey Greenberg, all of the UW Department of Earth and Space Sciences; and Liu Yuping of the Chengdu Institute of Geology and Mineral Resources in Chengdu, China.

The smaller lake appears to have coincided with China’s Tang Dynasty and appears to have been the border between China and Tibet, Montgomery said. When the lake suddenly drained, it opened a large amount of rich farmland on the valley floor, farmland that today serves as the Tibetan breadbasket.

The Tsangpo River Gorge is considered some of the most spectacular terrain on Earth, as the river drops 7,800 feet (about 1.3 miles) in elevation over the course of about 125 miles. Parts of the gorge still have not been mapped because they are so rugged, possible evidence of the repeated sudden barrages of vast amounts of water unleashed by broken ice dams.

"You can carve a lot of beautiful deep valleys that way," Montgomery said. "To a geologist, that opens the question of, ’What is the role of these big floods? Are they responsible for carving that beautiful topography or are they merely second-bit players?’"

Vince Stricherz | EurekAlert!
Further information:
http://www.washington.edu

More articles from Earth Sciences:

nachricht NASA finds newly formed tropical storm lan over open waters
17.10.2017 | NASA/Goddard Space Flight Center

nachricht The melting ice makes the sea around Greenland less saline
16.10.2017 | Aarhus University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Osaka university researchers make the slipperiest surfaces adhesive

18.10.2017 | Materials Sciences

Space radiation won't stop NASA's human exploration

18.10.2017 | Physics and Astronomy

Los Alamos researchers and supercomputers help interpret the latest LIGO findings

18.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>