Featured Research

from universities, journals, and other organizations

Magnetic anomaly deep within Earth's crust reveals Africa in North America

Date:
April 2, 2014
Source:
Geological Society of America
Summary:
The repeated cycles of plate tectonics that have led to collision and assembly of large supercontinents and their breakup and formation of new ocean basins have produced continents that are collages of bits and pieces of other continents. Figuring out the origin and make-up of continental crust formed and modified by these tectonic events is vital to understanding Earth's geology and is important for many applied fields, such as oil, gas, and gold exploration.

The repeated cycles of plate tectonics that have led to collision and assembly of large supercontinents and their breakup and formation of new ocean basins have produced continents that are collages of bits and pieces of other continents. Figuring out the origin and make-up of continental crust formed and modified by these tectonic events is a vital to understanding Earth's geology and is important for many applied fields, such as oil, gas, and gold exploration.

Related Articles


In many cases, the rocks involved in these collision and pull-apart episodes are still buried deep beneath Earth's surface, so geologists must use geophysical measurements to study these features.

This new study by Elias Parker Jr. of the University of Georgia examines a prominent swath of lower-than-normal magnetism -- known as the Brunswick Magnetic Anomaly -- that stretches from Alabama through Georgia and off shore to the North Carolina coast.

The cause of this magnetic anomaly has been under some debate. Many geologists attribute the Brunswick Magnetic Anomaly to a belt of 200 million year old volcanic rocks that intruded around the time the Atlantic Ocean. In this case, the location of this magnetic anomaly would then mark the initial location where North America split from the rest of Pangea as that ancient supercontinent broke apart. Parker proposes a different source for this anomalous magnetic zone.

Drawing upon other studies that have demonstrated deeply buried metamorphic rocks can also have a coherent magnetic signal, Parker has analyzed the detailed characteristics of the magnetic anomalies from data collected across zones in Georgia and concludes that the Brunswick Magnetic Anomaly has a similar, deeply buried source. The anomalous magnetic signal is consistent with an older tectonic event -- the Alleghanian orogeny that formed the Alleghany-Appalachian Mountains when the supercontinent of Pangea was assembled.

Parker's main conclusion is that the rocks responsible for the Brunswick Magnetic Anomaly mark a major fault-zone that formed as portions of Africa and North America were sheared together roughly 300 million years ago -- and that more extensive evidence for this collision are preserved along this zone. One interesting implication is that perhaps a larger portion of what is now Africa was left behind in the American southeast when Pangea later broke up.


Story Source:

The above story is based on materials provided by Geological Society of America. Note: Materials may be edited for content and length.


Journal Reference:

  1. E.H. Parker, Jr. Crustal magnetism, tectonic inheritance, and continental rifting in the southeastern United States. GSA Today, 2014; 24 (4): 4 DOI: 10.1130/GSAT-G192A.1

Cite This Page:

Geological Society of America. "Magnetic anomaly deep within Earth's crust reveals Africa in North America." ScienceDaily. ScienceDaily, 2 April 2014. <www.sciencedaily.com/releases/2014/04/140402162458.htm>.
Geological Society of America. (2014, April 2). Magnetic anomaly deep within Earth's crust reveals Africa in North America. ScienceDaily. Retrieved March 6, 2015 from www.sciencedaily.com/releases/2014/04/140402162458.htm
Geological Society of America. "Magnetic anomaly deep within Earth's crust reveals Africa in North America." ScienceDaily. www.sciencedaily.com/releases/2014/04/140402162458.htm (accessed March 6, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Friday, March 6, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Late Winter Storm Wreaks Havoc Across Eastern US

Late Winter Storm Wreaks Havoc Across Eastern US

AP (Mar. 5, 2015) — A strong cold front moving across the eastern U.S. has dumped deep snow in some regions, creating hazardous conditions from Kentucky to New England. (March 5) Video provided by AP
Powered by NewsLook.com
Keurig Co-Founder Says Company Has A Waste Problem

Keurig Co-Founder Says Company Has A Waste Problem

Newsy (Mar. 5, 2015) — Keurig co-founder John Sylvan told The Atlantic he doesn&apos;t even own a Keurig because they&apos;re too expensive and produce too much waste. Video provided by Newsy
Powered by NewsLook.com
Raw: Tourists Visit Rare Grey Whales in Mexico

Raw: Tourists Visit Rare Grey Whales in Mexico

AP (Mar. 4, 2015) — Once nearly extinct, grey whales now migrate in their thousands to Mexico&apos;s Vizcaino reserve in Baja California, in search of warmer waters to mate and give birth. Tourists flock to the reserve to see the whales, measuring up to 49 feet long. (March 4) Video provided by AP
Powered by NewsLook.com
Raw: Injured Miners Treated After Blast

Raw: Injured Miners Treated After Blast

AP (Mar. 4, 2015) — An explosion ripped through a coal mine before dawn Wednesday in war-torn eastern Ukraine, killing at least one miner, officials said. Graphic video of injured miners being treated in a Donetsk hospital. (March 4) 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:

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