Posted on 07/06/2011 12:16:41 PM PDT by decimon
'Hot spots' of plume from deep Earth could propel plate motions around globe
Bringing fresh insight into long-standing debates about how powerful geological forces shape the planet, from earthquake ruptures to mountain formations, scientists at Scripps Institution of Oceanography at UC San Diego have identified a new mechanism driving Earth's massive tectonic plates.
Scientists who study tectonic motions have known for decades that the ongoing "pull" and "push" movements of the plates are responsible for sculpting continental features around the planet. Volcanoes, for example, are generally located at areas where plates are moving apart or coming together. Scripps scientists Steve Cande and Dave Stegman have now discovered a new force that drives plate tectonics: Plumes of hot magma pushing up from Earth's deep interior. Their research is published in the July 7 issue of the journal Nature.
Using analytical methods to track plate motions through Earth's history, Cande and Stegman's research provides evidence that such mantle plume "hot spots," which can last for tens of millions of years and are active today at locations such as Hawaii, Iceland and the Galapagos, may work as an additional tectonic driver, along with push-pull forces.
Their new results describe a clear connection between the arrival of a powerful mantle plume head around 70 million years ago and the rapid motion of the Indian plate that was pushed as a consequence of overlying the plume's location. The arrival of the plume also created immense formations of volcanic rock now called the "Deccan flood basalts" in western India, which erupted just prior to the mass extinction of dinosaurs. The Indian continent has since drifted north and collided with Asia, but the original location of the plume's arrival has remained volcanically active to this day, most recently having formed Réunion island near Madagascar.
The team also recognized that this "plume-push" force acted on other tectonic plates, and pushed on Africa as well but in the opposite direction.
"Prior to the plume's arrival, the African plate was slowly drifting but then stops altogether, at the same time the Indian speeds up," explains Stegman, an assistant professor of geophysics in Scripps' Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics. "It became clear the motion of the Indian and African plates were synchronized and the Réunion hotspot was the common link."
After the force of the plume had waned, the African plate's motion gradually returned to its previous speed while India slowed down.
"There is a dramatic slow down in the northwards motion of the Indian plate around 50 million years ago that has long been attributed to the initial collision of India with the Eurasian plate," said Cande, a professor of marine geophysics in the Geosciences Research Division at Scripps. "An implication of our study is that the slow down might just reflect the waning of the mantle plume-the actual collision might have occurred a little later."
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Funding for the research was provided by the National Science Foundation.
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About Scripps Institution of Oceanography
Scripps Institution of Oceanography at University of California, San Diego, is one of the oldest, largest and most important centers for global science research and education in the world. Now in its second century of discovery, the scientific scope of the institution has grown to include biological, physical, chemical, geological, geophysical and atmospheric studies of the earth as a system. Hundreds of research programs covering a wide range of scientific areas are under way today in 65 countries. The institution has a staff of about 1,400, and annual expenditures of approximately $170 million from federal, state and private sources. Scripps operates robotic networks, and one of the largest U.S. academic fleets with four oceanographic research ships and one research platform for worldwide exploration. Birch Aquarium at Scripps serves as the interpretive center of the institution and showcases Scripps research and a diverse array of marine life through exhibits and programming for more than 415,000 visitors each year. Learn more at scripps.ucsd.edu.
Plume push ping.
Oh bull, this is all driven by global warming and they know it.
.
Beat me to it.
So, when will the Idaho/Yellowstone hot spot blow again?
Planning your vacation?
I was thinking about moving there for a decade or so.
One of the most beautiful areas in the country. Envious.
What would you do there?
Steve Cande and Dave Stegman have now discovered a new force that drives plate tectonics: Plumes of hot magma pushing up from Earth's deep interior... evidence that such mantle plume "hot spots," which can last for tens of millions of years and are active today at locations such as Hawaii, Iceland and the Galapagos, may work as an additional tectonic driver, along with push-pull forces.Thanks decimon.
Fossil Mantle Plume Under South America"In a challenge to a major aspect of the theory of plate tectonics, NSF-supported scientists have discovered the presence of an ancient conduit deep in the Earth's mantle beneath Brazil.
by William R. Corliss
Science Frontiers #103: Jan-Feb 1996
"The conduit appears to have remained geographically fixed with respect to the overlying continent despite thousands of kilometers of South American plate motion. This observation runs contrary to a major tenet of plate tectonic theory---that the motion of lithospheric plates is essentially independent of flow in the upper mantle beneath the plates--- and implies that the upper mantle and the overlying South American continent have remained coupled since the breakup of the Gondwanaland super-continent and opening of the South Atlantic Ocean some 120 million years ago. This result also implies that large-scale convection in the mantle may be responsible for the motion of the great continental plates, such as South America, where the driving force for plate motion has not been well understood."
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Hang out with me.
Magma plumes, eh? They need to check every spot FA Moochelle has been...and forewarn all of her future vay-kay spots...
That is hilarious.
That is hilarious.
Do bears large in the woods? I guess they could have turned themselves in to a park ranger.
And added impersonating an Officer? I think they are in enough trouble as it is.
This can’t possibly be true.
I’ve been assured by omniscient naysayers on FR that everything true about geology was known long ago.
/sarc pseudo-joke
I’d go fishing until it was time to go skiing.
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