Featured Research

from universities, journals, and other organizations

Geological Demolition Derby: New View On Tibetan Plateau's Rift Valleys

Date:
November 18, 2004
Source:
University Of Arizona
Summary:
The spectacular rift valleys of the Tibetan plateau don't all run north-south as previously thought, according to new research. The rift valleys actually curve away -- some to the east, some to the west -- from the point where India is punching into the gut of Tibet.

A satellite's-eye-view of India and Tibet. Image from NASA's Terra satellite.
Credit: Photo credit: NASA

The spectacular rift valleys of the Tibetan plateau don't all run north-south as previously thought, according to new research.

The rift valleys actually curve away -- some to the east, some to the west -- from the point where India is punching into the gut of Tibet.

"Everyone looked at the rifts and said they went north-south," said Paul Kapp, assistant professor of geosciences at the University of Arizona in Tucson. "I looked and said -- they're not."

His work contradicts a leading theory that suggests the rifts are a consequence of Tibet flowing slowly out over India's northern edge.

The new research indicates the Tibetan plateau is being compressed between the Indian subcontinent to the south and the solid wall of the North China block. As a result, Tibet is splitting much like an orange squeezed by a vise.

Kapp's research challenges the idea that the 16,000-foot-high Tibetan plateau, the highest-elevation region on Earth, is losing elevation. Previous research reported the Tibetan plateau reached its highest elevation eight million years ago and is now slowly deflating as it spreads out over India.

"My hypothesis predicts that the plateau is getting higher. The other theory suggests the plateau is collapsing," he said.

"We're in a place where continents are slamming against each other. Instead of Tibet crumpling like an accordion, we see these rift valleys. The rifts are from the east-west stretching of the plateau."

The article, "India Punch Rifts Tibet," by Kapp and Jerome H. Guynn, a doctoral candidate in UA's department of geosciences, is in the November issue of the journal Geology. The research was funded by the UA Faculty Small Grants program.

Although the standard description says Tibet's rift valleys run north-south, that didn't square with what Kapp saw when he looked at topographic maps of the area.

The problem nagged at him for years.

In fall of 2003, he was teaching structural geology, and as he worked on the lecture about stress in the crust from continents colliding, he realized that collisional stress caused the pattern of Tibet's rift valleys. He remembers thinking, "Yeah, that's it!"

"It took me eight years to recognize the pattern," he said. "It took me two days to come up with an explanation."

Geologists often use digital elevation models, or DEMs, that are developed from satellite imagery. Such maps, which look like a shaded relief map, show the Earth's current surface in incredible detail.

Kapp said that the detailed nature of such maps obscures the underlying pattern of the rifts.

So Kapp and Guynn used a computer to strip away the DEM's superficial layers to expose the underlying structure of the plateau. Once they created a bare-bones map of the region, the curving patterns of the rifts were clear.

"I took away all the secondary faults and then the pattern jumped out," Kapp said.

Because India is crashing into Tibet, geologists call India "the indentor." Kapp says that because India is hitting Tibet head-on, the Tibetan plateau is developing splits, or rifts, that curve away from the axis of impact.

Once Kapp figured out what caused the rifts, he and Guynn created mathematical models to test the idea. According to the models, a head-on punch split the plateau just the way Kapp predicted.

In addition to punching Tibet directly, a lower portion of the Indian subcontinent is sliding under Tibet and lifting the plateau, Kapp said.

Measuring how much Tibet is moving up or down is extremely difficult, although the technology is getting better all the time.

"I think there will be some serious arguing for probably the next five years."

The Himalayas and Tibet are an area of active research by many groups of geologists. Kapp said, "If you want to understand mountain-building, you go there."

Kapp and Guynn are among them. This summer they'll be there scanning the region's rocks for more evidence to support their new theory.


Story Source:

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


Cite This Page:

University Of Arizona. "Geological Demolition Derby: New View On Tibetan Plateau's Rift Valleys." ScienceDaily. ScienceDaily, 18 November 2004. <www.sciencedaily.com/releases/2004/11/041116234241.htm>.
University Of Arizona. (2004, November 18). Geological Demolition Derby: New View On Tibetan Plateau's Rift Valleys. ScienceDaily. Retrieved August 23, 2014 from www.sciencedaily.com/releases/2004/11/041116234241.htm
University Of Arizona. "Geological Demolition Derby: New View On Tibetan Plateau's Rift Valleys." ScienceDaily. www.sciencedaily.com/releases/2004/11/041116234241.htm (accessed August 23, 2014).

Share This




More Earth & Climate News

Saturday, August 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Airlines on Iceland Volcano Alert

Airlines on Iceland Volcano Alert

Reuters - Business Video Online (Aug. 22, 2014) Iceland evacuates an area north of the country's Bardarbunga volcano, as the country's civil protection agency says it cannot rule out an eruption. Authorities have already warned airlines. As Joel Flynn reports, ash from the eruption of the Eyjafjallajokull volcano in 2010 shut down much of Europe's airspace for six days. Video provided by Reuters
Powered by NewsLook.com
Endangered Red Wolves Face Uncertain Future

Endangered Red Wolves Face Uncertain Future

AP (Aug. 22, 2014) A federal judge temporarily banned coyote hunting to save endangered red wolves, but local hunters say that the wolf preservation program does more harm than good. Meanwhile federal officials are reviewing its wolf program in North Carolina. (Aug. 22) Video provided by AP
Powered by NewsLook.com
Coal Gas Boom in China Holds Climate Risks

Coal Gas Boom in China Holds Climate Risks

AP (Aug. 22, 2014) China's energy revolution could do more harm than good for the environment, despite the country's commitment to reducing pollution and curbing its carbon emissions. (Aug. 22) Video provided by AP
Powered by NewsLook.com
Microbrewery Chooses Special Can for Its Beer

Microbrewery Chooses Special Can for Its Beer

AP (Aug. 22, 2014) Aluminum giant, Novelis, has partnered with Red Hare Brewing Company to introduce the first certified high-content recycled beverage can. (Aug. 22) Video provided by AP
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:
from the past week

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