HomeLatest ThreadsGreatest ThreadsForums & GroupsMy SubscriptionsMy Posts
DU Home » Latest Threads » Forums & Groups » Topics » Science » Science (Group) » Location of upwelling in ...

Wed Jun 26, 2013, 09:04 PM

Location of upwelling in Earth's mantle discovered to be stable


This is a diagram showing a slice through the Earth's mantle, cutting across major mantle upwelling locations beneath Africa and the Pacific. Credit: C. Conrad (UH SOEST)

A study published in Nature today shares the discovery that large-scale upwelling within Earth's mantle mostly occurs in only two places: beneath Africa and the Central Pacific. More importantly, Clinton Conrad, Associate Professor of Geology at the University of Hawaii Manoa's School of Ocean and Earth Science and Technology (SOEST) and colleagues revealed that these upwelling locations have remained remarkably stable over geologic time, despite dramatic reconfigurations of tectonic plate motions and continental locations on the Earth's surface.

"For example," said Conrad, "the Pangaea supercontinent formed and broke apart at the surface, but we think that the upwelling locations in the mantle have remained relatively constant despite this activity."

Conrad has studied patterns of tectonic plates throughout his career, and has long noticed that the plates were, on average, moving northward. "Knowing this," explained Conrad, "I was curious if I could determine a single location in the Northern Hemisphere toward which all plates are converging, on average." After locating this point in eastern Asia, Conrad then wondered if other special points on Earth could characterize plate tectonics. "With some mathematical work, I described the plate tectonic 'quadrupole', which defines two points of 'net convergence' and two points of 'net divergence' of tectonic plate motions."

When the researchers computed the plate tectonic quadruople locations for present-day plate motions, they found that the net divergence locations were consistent with the African and central Pacific locations where scientists think that mantle upwellings are occurring today. "This observation was interesting and important, and it made sense," said Conrad. "Next, we applied this formula to the time history of plate motions and plotted the points - I was astonished to see that the points have not moved over geologic time!" Because plate motions are merely the surface expression of the underlying dynamics of the Earth's mantle, Conrad and his colleagues were able to infer that upwelling flow in the mantle must also remain stable over geologic time. "It was as if I was seeing the 'ghosts' of ancient mantle flow patterns, recorded in the geologic record of plate motions!"

more
http://phys.org/news/2013-06-upwelling-earth-mantle-stable.html

1 replies, 931 views

Reply to this thread

Back to top Alert abuse

Always highlight: 10 newest replies | Replies posted after I mark a forum
Replies to this discussion thread
Arrow 1 replies Author Time Post
Reply Location of upwelling in Earth's mantle discovered to be stable (Original post)
n2doc Jun 2013 OP
madrchsod Jun 2013 #1

Response to n2doc (Original post)

Wed Jun 26, 2013, 09:39 PM

1. interesting...

thanks for posting

Reply to this post

Back to top Alert abuse Link here Permalink

Reply to this thread