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posted by janrinok on Monday December 19 2016, @04:09PM   Printer-friendly
from the blowing-hot-and-cold dept.

The thickness of new volcanic crust forming on the seafloor has gotten thinner over the last 170 million years. That suggests that the underlying mantle is cooling about twice as fast as previously thought, researchers reported December 13 at the American Geophysical Union's fall meeting.

The rapid mantle cooling offers fresh insight into how plate tectonics regulates Earth's internal temperature, said study coauthor Harm Van Avendonk, a geophysicist at the University of Texas at Austin. "We're seeing this kind of thin oceanic crust on the seafloor that may not have existed several hundred million years ago," he said. "We always consider that the present is the clue to the past, but that doesn't work here."

The finding is fascinating, though the underlying data is sparse, said Laurent Montési, a geodynamicist at the University of Maryland in College Park. Measuring the thickness of seafloor crust requires seismic studies, and "you don't have that everywhere; there's nothing in the South Pacific, for example." Still, he said, "it's amazing that we can see the signature of the cooling of the Earth." The finding could help explain why supercontinents such as Pangaea break apart, he added.


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  • (Score: 0) by Anonymous Coward on Monday December 19 2016, @07:01PM

    by Anonymous Coward on Monday December 19 2016, @07:01PM (#443260)

    I was going to make a joke about how geothermal energy production is causing lithospheric cooling but this is one tough crowd.

  • (Score: 3, Interesting) by vux984 on Monday December 19 2016, @07:08PM

    by vux984 (5045) on Monday December 19 2016, @07:08PM (#443265)

    Geothermal is clearly not a renewable resource. ;)

    • (Score: 2) by Azuma Hazuki on Monday December 19 2016, @08:13PM

      by Azuma Hazuki (5086) on Monday December 19 2016, @08:13PM (#443299) Journal

      If we're gonna be pedantic, neither is solar. However, our world's inner heat, to say nothing of its central star, will far, far outlast the human race. ...on bad days I sometimes think the average discarded Yoplait container will outlast the human race :(

      --
      I am "that girl" your mother warned you about...
      • (Score: 2) by vux984 on Tuesday December 20 2016, @01:52AM

        by vux984 (5045) on Tuesday December 20 2016, @01:52AM (#443489)

        If we're gonna be pedantic, neither is solar.

        True, but consuming or not consuming solar energy doesn't affect the source. The sun has *already* radiated that energy away, whether we use it here or not. Geothermal, at least in theory, is actually actively cooling the earth more than it would have otherwise; especially when we start drilling holes in the crust to get it out even faster. ;)

        • (Score: 2) by tathra on Tuesday December 20 2016, @05:43AM

          by tathra (3367) on Tuesday December 20 2016, @05:43AM (#443570)

          geothermal is definitely something we should not think about overusing. iirc, most of the core's heat comes from the decay of radioactive aluminum and other metals, and only a little bit from tidal heating. if we drain away too much heat, that really would mean the planet's death - no magnetic field, no plate tectonics, just a dead, lifeless rock scorched by solar wind and radiation and unable to hold on to an atmosphere. we need to figure out exactly how fast the mantle and core are cooling and how internal temperature correlates to magnetic field intensity, then we could try to figure out exactly how much heat we could draw off before having to worry. the answer would probably be far more than we could realistically use over the next [couple?] billion years, but still, we should focus on solar rather than geothermal since solar works just as well in space too, so the technology and investments will be infinitely more useful and unused stellar energy is going to waste anyway.