Featured Research

from universities, journals, and other organizations

Geophysicists Propose A New Model Of Earth's Mantle

Date:
March 19, 1999
Source:
University of California, Davis
Summary:
Earth's mantle, a region as scientifically remote as outer space and the object of the most heated debate in geophysics, gets a remodeling this Friday by researchers at UC Davis and MIT.

Earth's mantle, a region as scientifically remote as outer space and the object of the most heated debate in geophysics, gets a remodeling this Friday by researchers at UC Davis and MIT.

Related Articles


Sandwiched between Earth's crust and molten outer core, the vast mantle accounts for 83 percent of the planet's volume. It is filled with solid rock but, heated by the core and by its own radioactive decay, it circulates like a pot of impenetrable soup. That circulation is the driving force behind the surface motion of tectonic plates, which builds mountains and causes earthquakes.

For almost 50 years scientists have debated how the mantle circulates -- in one layer or two? Recent work by seismologists shows that tectonic plates sink from the Earth's surface deep into the lower mantle, suggesting that the mantle overturns as a single layer. However, the Earth's heat budget and geochemists' studies of the chemical composition of rocks erupted at volcanic islands indicate that large sections of the mantle have remained isolated from the surface since the Earth formed, suggesting that there must be two layers.

Writing in the March 19 issue of the journal Science, UC Davis geophysicist Louise Kellogg and her MIT collaborators try to resolve the conflict.

They propose that there are indeed two mantle layers. In their model, tectonic plates do dive very deep into the mantle, but encounter a geological barrier at about two-thirds of the distance to the outer core. This jibes with the seismic records.

When the sinking plate reaches this barrier, it is deflected and largely prevented from mixing with the deep-mantle material. But at a few spots on that geological boundary, hot plumes rise up, pulling a bit of deep-mantle material along with the ancient slab to the surface, erupting in volcanic islands. That would explain the geochemists' findings.

"This is where I come in. I try to merge the time history of the geochemist and the snapshot of the seismologist," says Kellogg, who attacked the problem by computer modeling of fluid dynamics.

Kellogg's MIT co-authors are Brad Hager and Rob van der Hilst. The work was funded by the National Science Foundation.

Kellogg, 39, was one of the first recipients of a $500,000 national Presidential Faculty Fellowship. She is an associate professor of geology and vice chair of the UC Davis Geology Department. She received bachelor's degrees in philosophy and engineering physics in 1982, a master's in engineering physics in 1985 and a Ph.D. in geological sciences in 1988, all from Cornell University.


Story Source:

The above story is based on materials provided by University of California, Davis. Note: Materials may be edited for content and length.


Cite This Page:

University of California, Davis. "Geophysicists Propose A New Model Of Earth's Mantle." ScienceDaily. ScienceDaily, 19 March 1999. <www.sciencedaily.com/releases/1999/03/990319061058.htm>.
University of California, Davis. (1999, March 19). Geophysicists Propose A New Model Of Earth's Mantle. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/1999/03/990319061058.htm
University of California, Davis. "Geophysicists Propose A New Model Of Earth's Mantle." ScienceDaily. www.sciencedaily.com/releases/1999/03/990319061058.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) — The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Arctic Warming Twice As Fast As Rest Of Planet

Arctic Warming Twice As Fast As Rest Of Planet

Newsy (Dec. 18, 2014) — The Arctic is warming twice as fast as the rest of the planet, thanks in part to something called feedback. Video provided by Newsy
Powered by NewsLook.com
Prenatal Exposure To Pollution Might Increase Autism Risk

Prenatal Exposure To Pollution Might Increase Autism Risk

Newsy (Dec. 18, 2014) — Harvard researchers found children whose mothers were exposed to high pollution levels in the third trimester were twice as likely to develop autism. Video provided by Newsy
Powered by NewsLook.com
Ivory Trade Boom Swamps Law Efforts

Ivory Trade Boom Swamps Law Efforts

Reuters - Business Video Online (Dec. 17, 2014) — Demand for ivory has claimed the lives of tens of thousands of African elephants and now a conservation report says the illegal trade is overwhelming efforts to enforce the law. Amy Pollock reports. Video provided by Reuters
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