Featured Research

from universities, journals, and other organizations

University of Michigan Study Solves Pangea Puzzle

Date:
December 19, 2000
Source:
University Of Michigan
Summary:
Researchers at the University of Michigan and the Geological Survey of Norway say they have solved a longstanding and controversial puzzle over the position of Pangea, the ancient supercontinent that began breaking up some 200 million years ago to form today's continents.

SAN FRANCISCO --- Researchers at the University of Michigan and the Geological Survey of Norway say they have solved a longstanding and controversial puzzle over the position of Pangea, the ancient supercontinent that began breaking up some 200 million years ago to form today's continents. They presented their findings Dec. 19 at a meeting of the American Geophysical Union here.

Related Articles


Scientists have long known that the continents are not fixed in place on Earth's surface, but gradually change positions over millions of years. Based on geological evidence, researchers have come up with several models that show how the continents might have fit together when they were tightly clustered. One widely accepted model, dubbed Pangea A and reproduced in countless textbooks, shows what is now South America nestled against the southern edge of North America, with Africa just east of South America, adjacent to the Atlantic coast of North America and southwest of Europe.

But geologists who study paleomagnetic data---records of Earth's magnetic field captured in rocks over eons---have been troubled by data that just don't fit the Pangea A model. Paleomagnetic data reveal the latitude at which rocks were located when the magnetization was recorded. That information, in turn, provides clues to the positions of the continents.

The problem is that, according to the paleomagnetic data, "the southern continents should be a little bit farther north" than they are in the Pangea A model, explains Rob Van der Voo, a professor of geological sciences at U-M. That dilemma has led to alternative models that place northwestern South America along the east coast of North America or push it even farther east to lie just south of Europe. While the revised models may satisfy researchers who specialize in paleomagnetism, they gall other geologists who find no evidence in fossils or mountain chains to suggest that the continents have ever been in those positions.

Now, Van der Voo and colleague Trond Torsvik of the Geological Survey of Norway have found a way to reconcile the paleomagnetic data with the classical Pangea A model. The key, they say, lies in assumptions about Earth's magnetic field. Scientists generally have assumed the field is like that of a dipole, an object such as a bar magnet, with north and south magnetic poles. That view is not exactly correct---the field does have some non-dipole components today---but because those components vary from century to century, they have been presumed to cancel out over long spans of time.

But suppose, says Van der Voo, "that the main magnetic field wasn't what we have always assumed as perfectly dipolar---that there was a longstanding non-dipolar field that did not get averaged out." If that were true, positions indicated by paleomagnetic data would be slightly different from those that assume a purely dipolar field. Sure enough, when Van der Voo and Torsvik performed an analysis they found long-term non-dipole fields, and inclusion of these fields produced a near perfect continental fit with the Pangea A model.

"The broader implications of this study," says Van der Voo, "are that paleomagnetic results for other times and other continental configurations must now be re-evaluated with the new geomagnetic field model that should include some 10 percent non-dipole fields, and this will keep us busy for decades."


Story Source:

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


Cite This Page:

University Of Michigan. "University of Michigan Study Solves Pangea Puzzle." ScienceDaily. ScienceDaily, 19 December 2000. <www.sciencedaily.com/releases/2000/12/001218110642.htm>.
University Of Michigan. (2000, December 19). University of Michigan Study Solves Pangea Puzzle. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2000/12/001218110642.htm
University Of Michigan. "University of Michigan Study Solves Pangea Puzzle." ScienceDaily. www.sciencedaily.com/releases/2000/12/001218110642.htm (accessed October 24, 2014).

Share This



More Earth & Climate News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

Reuters - Light News Video Online (Oct. 22, 2014) The pair of rare white northern rhinos bring hope for their species as only six remain in the world. Elly Park reports. Video provided by Reuters
Powered by NewsLook.com
Trick-or-Treating Banned Because of Polar Bears

Trick-or-Treating Banned Because of Polar Bears

Buzz60 (Oct. 21, 2014) Mother Nature is pulling a trick on the kids of Arviat, Canada. As Mara Montalbano (@maramontalbano) tells us, the effects of global warming caused the town to ban trick-or-treating this Halloween. Video provided by Buzz60
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
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