 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Deep Magmatic Plumbing Of Mid-Ocean Ridges Revealed
New York NY (SPX) Aug 25, 2005 Some of the highest quality images ever taken of the Earth's lower crust reveal that the upper and lower crust form in two distinctly different ways. A team led by researchers from Columbia University's Lamont-Doherty Earth Observatory will publish the results of their work in the August 25 issue of the journal Nature. The Earth's oceanic crust is formed from magma bodies located beneath mid-ocean ridges. Although axial magma chambers, magma bodies located in the mid-crust, are known to be responsible for generating the upper oceanic crust, it has so far been unclear if the lower crust is formed from the same source or if it primarily arises from deeper "magma lenses" -- smaller bodies located at or near the base of the crust. Researchers from Lamont-Doherty as well as the Scripps Institution of Oceanography and the Woods Hole Oceanographic Institution collected seismic data of the oceanic crust beneath the seafloor off the coast of Washington, Oregon and northern California. To form the images, they analyzed sound waves that bounced off of structures deep in the Earth, a process similar to that of creating an ultrasound image. The resulting images are the first of their kind showing solidified lenses and sills, narrow lateral intrusions of magma, embedded within the crust/mantle boundary known as the Moho transition zone. The presence of such bodies that deep near a mid-ocean ridge suggests that the lower crust is at least partially formed from several smaller sources of magma rather than from a single large source located in the middle of the crust. "This demonstrates quite strongly that the process of crustal formation is more complex than generally believed," said Mladen Nedimovic, lead author on the study and a Doherty Associate Research Scientist at Lamont-Doherty. "It also favors the emerging view that volcanoes have a complicated plumbing system consisting of many interconnected sills and magma conduits. We obviously still have a lot to learn about what goes on beneath the surface of the Earth." Community Email This Article Comment On This Article Related Links The Earth Institute at Columbia University SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express Tectonic Science and News
Ash Continuing To Spew From Vanuatu Volcano
Sydney (AFP) Dec 12, 2005Thousands of tonnes of ash are continuing to spew from a volcano in Vanuatu, but officials said Monday the activity on the South Pacific nation was not likely to result in a major deadly eruption. |
|
|
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement |
