Featured Research

from universities, journals, and other organizations

Study Of Erosion And Precipitation In The Himalayas Presents Surprising Findings Scholars Say

Date:
December 12, 2003
Source:
University Of California - Santa Barbara
Summary:
Scientists have found that, despite a vast difference in precipitation between the north and south sides of the Himalaya Mountains, rates of erosion are indistinguishable across these mountains.

Santa Barbara, Calif. –– Scientists have found that, despite a vast difference in precipitation between the north and south sides of the Himalaya Mountains, rates of erosion are indistinguishable across these mountains.

Related Articles


Douglas Burbank, professor of geology and director of the Institute for Crustal Studies at the University of California, Santa Barbara, is the first author of the article, "Decoupling of erosion and precipitation in the Himalayas," to be published Thursday, December 11, in the international scientific journal Nature.

This four-year study of the interactions between climate, erosion and tectonic deformation was funded by the National Science Foundation. The Himalayas were chosen because of their unique combination of massive topography, monsoon rains, and rapid erosion.

The study relies on a network of 20 weather stations arrayed across the Himalayas. Jaakko Putkonen of the University of Washington installed and maintains the weather stations. These stations are unique in that many of them are located on mountain tops as high as 15,000 feet, whereas nearly all weather stations around the world are located in valleys.

Burbank and his team found that the difference in precipitation between the north and south is striking. The monsoon rains that originate over the Indian Ocean are drawn toward the Himalayas. As monsoon storms rise over the mountains, their moisture is wrung out of them, drenching the south side of the Himalayas with 15 feet of rainfall each summer. By contrast, to the north of the Himalayan summits, summer rainfall amounts to only about one foot. "Given this profound difference in rainfall, we expected to see large differences in rates of erosion. But this is not what we found," said Burbank.

Additionally, he explained that the tectonic plate of India is colliding with and thrusting under that of Asia at a rate of about two inches per year. About half of that collision is absorbed by the Himalayas, thrusting the mountains upward between India and Tibet. When coupled with erosion, this thrusting carries rocks to the surface from deep in the Earth's crust.

As rocks move toward the surface, they cool, and this cooling provides the researchers with a means to measure erosion at geological time scales of millions of years. Using a mineral-dating technique called fission-track dating, co-author Ann Blythe at the University of Southern California showed that it took about a half a million years for Himalayan rocks to cool from about 280 degrees Fahrenheit to surface temperatures. Because temperatures of 280 degrees occur one to two miles deep in the crust, Blythe's dating implies that two to four miles of rock are eroded from the Himalaya every million years.

Not only are these rates of erosion rapid, but they show no significant variation from the monsoon-drenched flank of the Himalaya to the arid conditions north of the range. This unexpected discovery led the researchers to search for the cause of this uniform erosion.

They noted that, as the climate gets drier, the mountainsides get steeper. Such steep slopes can cause landslides (and erosion) more easily with less rainfall than a gentle slope. Also, glaciers periodically advance across the northern areas and may erode very efficiently, despite the drier climate. Burbank and his team also proposed that river channels get narrower in the drier areas, thus concentrating more energy on the bedrock and eroding it just as fast as in the wetter areas.

The importance of this study, he said, lies in the fact that erosion rates are not closely linked to the dramatic changes in climate. Instead, the collision of India and Asia drives rocks steadily upward in the Himalaya and erosion sweeps them rapidly away.

In this project, Burbank is spearheading work by scholars at six other universities besides UCSB: Harvard, Dartmouth, MIT, University of Southern California, University of Washington, and the University of Wyoming. They work with the Nepalese Department of Hydrology and Meteorology.


Story Source:

The above story is based on materials provided by University Of California - Santa Barbara. Note: Materials may be edited for content and length.


Cite This Page:

University Of California - Santa Barbara. "Study Of Erosion And Precipitation In The Himalayas Presents Surprising Findings Scholars Say." ScienceDaily. ScienceDaily, 12 December 2003. <www.sciencedaily.com/releases/2003/12/031211074732.htm>.
University Of California - Santa Barbara. (2003, December 12). Study Of Erosion And Precipitation In The Himalayas Presents Surprising Findings Scholars Say. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2003/12/031211074732.htm
University Of California - Santa Barbara. "Study Of Erosion And Precipitation In The Himalayas Presents Surprising Findings Scholars Say." ScienceDaily. www.sciencedaily.com/releases/2003/12/031211074732.htm (accessed October 25, 2014).

Share This



More Earth & Climate News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

EU Gets Climate Deal, UK PM Gets Knock

EU Gets Climate Deal, UK PM Gets Knock

Reuters - Business Video Online (Oct. 24, 2014) EU leaders achieve a show of unity by striking a compromise deal on carbon emissions. But David Cameron's bid to push back EU budget contributions gets a slap in the face as the European Commission demands an extra 2bn euros. David Pollard reports. Video provided by Reuters
Powered by NewsLook.com
Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Raw: Tornado Rips Roofs in Washington State

Raw: Tornado Rips Roofs in Washington State

AP (Oct. 24, 2014) A rare tornado ripped roofs off buildings, uprooted trees and shattered windows Thursday afternoon in the southwest Washington city of Longview, but there were no reports of injuries. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Fast-Moving Lava Headed For Town On Hawaii's Big Island

Fast-Moving Lava Headed For Town On Hawaii's Big Island

Newsy (Oct. 24, 2014) Lava from the Kilauea volcano on Hawaii's Big Island has accelerated as it travels toward a town called Pahoa. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins