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 Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute

nachricht Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>