Geologic time-scale for recyling of planet’s crust 4 times faster than previously thought

August 11, 2011HAWAII – The recycling of the Earth’s crust in volcanoes happens much faster than scientists have previously assumed. Rock of the oceanic crust, which sinks deep into the earth due to the movement of tectonic plates, reemerges through volcanic eruptions after around 500 million years. German researchers from the Max Planck Institute for Chemistry in Mainz obtained this result using volcanic rock samples. Previously, geologists thought this process would take about two billion years. Virtually all of the ocean islands are volcanoes. Several of them, such as Hawaii, originate from the lowest part of the mantle. This geological process is similar to the movement of colored liquids in a lava lamp: hot rock rises in cylindrical columns, the so-called mantle plumes, from a depth of nearly 3000 kilometers. Near the surface, it melts, because the pressure is reduced, and forms volcanoes. The plume originates from former ocean crust which early in the Earth’s history sank to the bottom of the mantle. Previously, scientists had assumed that this recycling took about two billion years. The chemical analysis of tiny glassy inclusions in olivine crystals from basaltic lava on Mauna Loa volcano in Hawaii has now surprised geologists: the entire recycling process requires at most half a billion years, four times faster than previously thought. To their surprise, the Max Planck researchers found residues of sea water with an unexpected strontium isotope ratio in the samples, which suggested an age of less than 500 million years for the inclusions. Therefore the rock material forming the Hawaiian basalts must be younger. “Apparently strontium from sea water has reached deep in the Earth’s mantle, and reemerged after only half a billion years, in Hawaiian volcano lavas,” says Klaus Peter Jochum, co-author of the publication. “This discovery was a huge surprise for us.” Another surprise for the scientists was the tremendous variation of strontium isotope ratios found in the melt inclusions in olivine from the single lava sample. “This variation is much larger than the known range for all Hawaiian lavas”, says Alexander Sobolev. “This finding suggests that the mantle is far more chemically heterogeneous on a small spatial scale than we thought before.” –Physics.org
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6 Responses to Geologic time-scale for recyling of planet’s crust 4 times faster than previously thought

  1. Grammerbat says:

    The ever “recyling” crust…

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  2. Stephen says:

    Hi Alvin,

    Are you expecting something enormous and cataclysmic in the coming months of September and October?

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    • Stephen, I think things are accelerating overall but I think we also live on the precipice of a black swan event that will be the first in a series of shocks that will shatter the sphere of complacency around the human race.

      Like

  3. Brandon says:

    Alvin, I’m not sure i understand your reply to Stephen. What are you trying to say when you mention black swan?

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    • black swan event: http://en.wikipedia.org/wiki/Black_swan_theory

      1.The event is a surprise (to the observer).
      2.The event has a major impact.
      3. After its first recording, the event is rationalized by hindsight, as if it could have been expected

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      • idiotbox says:

        1 It will only be a surprise to those that are completely unobservant,being they are so asorbed with the lies that the “idiotbox” injects into their obese HydrogeMsgAspaertamed minds.

        2 Those that are in denial will be impacted the most (as soon as the price of big macs and cigarettes triples in price).

        3 It will only be rational to those described in answers 1 and 2, to the rest it will be just another coverup of the pending truth.

        Like

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