According to the Science Daily article Plate Tectonics May Grind To A Halt, Then Start Again (Carnegie Institution), one main aspect of the research being presented is the hypothesis that

suggests that plate tectonics may have ground to a halt at least once in our planet's history -- and may do so again

Specifically, the article states that geochemical evidence of igneous rocks from about a billion years ago suggests there was a lull in subduction processes, coinciding with evidence of the closing of a Pacific-like basin, forming the supercontinent Rodinia. The lulls also, according to the article's authors, in part explain that

By periodically clamping the lid on heat flow, intermittent plate tectonics may explain why the Earth has lost heat slower than current models predict. And the buildup of heat beneath stagnant plates may explain the occurrence of certain igneous rocks in the middle of continents away from their normal locations in subduction zones.

However, the article rather vaguely states that

Rodinia eventually split apart when subduction and plate tectonics resumed.

What geological mechanism would cause a 'restart' of plate tectonics, specifically subduction?

  • 1
    $\begingroup$ related: earthscience.stackexchange.com/questions/2421/… $\endgroup$ – plannapus Nov 19 '14 at 8:45
  • $\begingroup$ @plannapus yes, I saw that question and answer, any updates and further explanation of the answer in regards to subduction would be great. $\endgroup$ – user889 Nov 19 '14 at 8:50
  • $\begingroup$ indeed an explanation of the process by a geophysicist instead of a paleontologist would be appreciated :) $\endgroup$ – plannapus Nov 19 '14 at 9:06
  • $\begingroup$ @plannapus don't get me wrong, your explanation the linked question was excellent and inspired this question to dig a little further. $\endgroup$ – user889 Nov 19 '14 at 9:19
  • 1
    $\begingroup$ oh that wasn't sarcastic i would indeed love to see a geophysicist explain the process itself. $\endgroup$ – plannapus Nov 19 '14 at 9:33

Subduction is ultimately driven by the heat flow process of mantle convection. A mantle plume beneath a stable plate will ultimately cause that plate to split, a la the African rift zone we observe today.

The crust of the earth is very thin compared to the mass of flowing material beneath it. As my global geophysics prof taught us, the fact that the earth has a solid outer "skin" is a consequence of the thermal conditions around the earth's surface and geochemistry, but that has little to no effect on the thermal conditions within the planet that ultimately control thermal convection that expresses itself on the surface as plate motions. I.E., the thermal mass of the crust is inconsequential when considering the thermal mechanisms that drive the mantle and outer core. Heat makes the plate go!

On the surface, plates may move, be created or destroyed, but thermodynamics tells us these are consequences, not drivers. We may observe evidence of past situations where plates appear to be static with respect to the underlying mantle motions, but this does not reveal any new mechanism that would suggest plate tectonic theory would not predict such circumstances.

  • 1
    $\begingroup$ Could you add some references to your answer? $\endgroup$ – user889 Feb 13 '15 at 17:52
  • $\begingroup$ The only reference on my bookshelf at the moment is "The Solid Earth" by C.M.R. Fowler, Cambridge University Press, 1990. The overriding concept that I've always considered the key is that the mantle convection is like water in a pot over the fire. Once you understand that circulation, plate motion becomes simple to understand. The wiki on subduction seems to spell out these general concepts as well. The article on subduction and this article on plate tectonics are good places to start. $\endgroup$ – txpaulm Feb 13 '15 at 19:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy