Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

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

03.04.2014

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.


April-May GSA Today cover image.

In many cases, the rocks involved in these collision and pull-apart episodes are still buried deep beneath the 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.

ARTICLE
Crustal magnetism, tectonic inheritance, and continental rifting in the southeastern United States
E.H. Parker, Jr., University of Georgia, Dept. of Geology, 210 Field St., Athens, Georgia 30602, USA, ehparker@uga.edu. GSA Today, v. 24, no. 4–5, p. 4-9; doi: 10.1130/GSAT-G192A.1.

GSA Today articles are open access online; for a print copy, please contact Kea Giles. Please discuss articles of interest with the authors before publishing stories on their work, and please make reference to GSA Today in articles published.

http://www.geosociety.org

Contact:
Kea Giles
Managing Editor,
GSA Communications
+1-303-357-1057
kgiles@geosociety.org

Kea Giles | EurekAlert!

Further reports about: Africa Atlantic GSA Magnetic anomaly collision supercontinent

More articles from Earth Sciences:

nachricht NASA eyes Pineapple Express soaking California
24.02.2017 | NASA/Goddard Space Flight Center

nachricht 'Quartz' crystals at the Earth's core power its magnetic field
23.02.2017 | Tokyo Institute of Technology

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

New pop-up strategy inspired by cuts, not folds

27.02.2017 | Materials Sciences

Sandia uses confined nanoparticles to improve hydrogen storage materials performance

27.02.2017 | Interdisciplinary Research

Decoding the genome's cryptic language

27.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>