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    Kansas Legislator Proposes Bill to Outlaw Sustainability Education

    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of sustainability. Here is a link to the one-page bill: http://www.kslegislature.org/li/b2013_14/measures/documents/hb2366_00_0000.pdf. See report on Bloomberg News.
  • Earth's Center Is 1,000 Degrees Hotter Than Previously Thought, Synchrotron X-Ray Experiment Shows
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    Earth's Center Is 1,000 Degrees Hotter Than Previously Thought, Synchrotron X-Ray Experiment Shows

    Scientists have determined the temperature near the Earth’s center to be 6000 degrees Celsius, 1000 degrees hotter than in a previous experiment run 20 years ago. These measurements confirm geophysical models that the temperature difference between the solid core and the mantle above, must be at least 1500 degrees to explain why the Earth has a magnetic field. For more information about this study, see the press release from the European Synchrotron Radiation Facility.
  • Ocean Volcanic Rocks Contain Samples of Recycled Crust
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    Ocean Volcanic Rocks Contain Samples of Recycled Crust

    Scientists have long believed that lava erupted from certain oceanic volcanoes contains materials from the early Earth’s crust. But decisive evidence for this phenomenon has proven elusive. New research from a team including Carnegie’s Erik Hauri demonstrates that oceanic volcanic rocks contain samples of recycled crust dating back to the Archean era 2.5 billion years ago. Their work is published in Nature. Oceanic crust sinks into the Earth’s mantle at so-called subduction zones, where two plates come together. Much of what happens to the crust during this journey is unknown. Model-dependent studies for how long subducted material can exist in the mantle are uncertain and evidence of very old crust returning to Earth’s surface via upwellings of magma has not been found until now. For more information about these results, see the press release from the Carnegie Institution.
This is an image of the Uruk Sulcus Region of Ganymede.
Click on image for full size
NASA

Ganymede Tectonism

There has been no icy volcanism on Ganymede, but it does seem that there has been a kind of tectonism, or surface motion.

Examination of the surface of Ganymede reveals many kinds of faulting and fracture. These provide evidence of stress (pushing and shoving) which the crust of Ganymede has undergone through time.

Examination of the surface of Ganymede shows:

  • Graben style faulting (another name for continental rifting)
  • Imbricate faulting (like a leaning stack of bricks)
Examination of the surface also shows a sequence of deformation, where the younger areas were deformed differently than the older areas.

This style of icy-tectonism proves to be different from either that of Callisto or Europa. (The other major moon of Jupiter, Io has a more conventional form of volcanism.) The difference has to do with processes in the interior of Ganymede


Last modified February 26, 2007 by Lisa Gardiner.

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