Geophysicists Find Source Behind “Sudden” Tectonic Plate Movements

Geophysicists Reveal the Details Behind Sudden Tectonic Plate Movements

Geophysicists from Yale University reveal that the combination of crustal plugs with weakening causes abrupt slab detachment in a few million years, which can account for observed precipitous changes in plate tectonic motion and rapid continental uplift.

Yale-led research may have solved one of the biggest mysteries in geology — namely, why do tectonic plates beneath the Earth’s surface, which normally shift over the course of tens to hundreds of millions of years, sometimes move abruptly?

A new study published January 19 in the journal Proceedings of the National Academy of Sciences says the answer comes down to two things: thick crustal plugs and weakened mineral grains. Those effects, acting together, may explain a range of relatively speedy moves among tectonic plates around the world, from Hawaii to East Timor.

Of course, in this case “speedy” still means a million years or longer.

“Our planet is probably most distinctly marked by the fact that it has plate tectonics,” said Yale geophysicist David Bercovici, lead author of the research. “Our work here looks at the evolution of plate tectonics. How and why do plates change directions over time?”

Traditionally, scientists believed that all tectonic plates are pulled by subducting slabs — which result from the colder, top boundary layer of the Earth’s rocky surface becoming heavy and sinking slowly into the deeper mantle. Yet that process does not account for sudden plate shifts. Such abrupt movement requires that slabs detach from their plates, but doing this quickly is difficult since the slabs should be too cold and stiff to detach.

According to the Yale study, there are additional factors at work. Thick crust from continents or oceanic plateaux is swept into the subduction zone, plugging it up and prompting the slab to break off. The detachment process is then accelerated when mineral grains in the necking slab start to shrink, causing the slab to weaken rapidly.

The result is tectonic plates that abruptly shift horizontally, or continents suddenly bobbing up.

“Understanding this helps us understand how the tectonic plates change through the Earth’s history,” Bercovici said. “It adds to our knowledge of the evolution of our planet, including its climate and biosphere.”

The study’s co-authors are Gerald Schubert of the University of California-Los Angeles and Yanick Ricard of the Université de Lyon in France.

Publication: David Bercovici, et al., “Abrupt tectonics and rapid slab detachment with grain damage,” PNAS, 2015; doi: 10.1073/pnas.1415473112

Image: Tectonic Plates from ShutterStock

2 Comments on "Geophysicists Find Source Behind “Sudden” Tectonic Plate Movements"

  1. No,it is during times of high magnetic induction, cosmic winds, that induct the conductive material of the earth, and so the pattern of mountain ranges for example is a record of our travel along the intergalactic plane as we pass through this area of the universe once every 110 million years. The regularity is observed in the symmetry of the mountain range formations. Evidence points to a ‘growing’ earth, that was smaller in the dinosaur times thus less gravity and larger everything…the earth is still flat.. maybe they will soon see.

  2. Don’t know who else to inform about this since already informed Philippines seismologists but they just replied saying they will forward my email to their head. For whatever possible conclusions/ actions… etc will come about this…. who knows BUT I JUST WANT TO SHARE THAT I HAVE NOTICED THE LAND ( of atleast my country) had been in CONSTANT MOVING MOTION SINCE MARCH of this year. I live in the Philippines and since beginning March I noticed that the land/ the ground / the earth had been in constant movement, like a swaying-pushing-tilting-accelerating on a very slow motion of movement. It feels like you’re on a huge cruise ship. This I felt in my house in the city, Then I moved to my beach house by the sea and still the exact movement is also happening here. Worse now I can actually see the movements with the mountains around me to my horror. Don’t know who to inform anymore but the entire country feels like it’s in a motion movement as one big mass of land. Is this the continental shift or something??? I am scared what if Philippines just starts to sink under the sea water? Someone please look into this as this may not just be a national emergency but a world wide emergency for earth.
    Desperate for some help here. Thanks

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