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Author Topic: Is Earth unique in having tectonic plates?  (Read 2467 times)

Offline chris

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Is Earth unique in having tectonic plates?
« on: 09/10/2013 23:52:07 »
Is Earth unique in having tectonic plates, or do other rocky worlds (or moons) show evidence of tectonic activity? If not, why not?


Offline CliffordK

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Re: Is Earth unique in having tectonic plates?
« Reply #1 on: 10/10/2013 01:15:57 »
What is a tectonic plate?

Is it a 3-level interface?  Solid crust, thin liquid lubrication layer, and an solid plate layer.  Hmmm, is that lubrication layer at least in part water?  Perhaps both continents and ocean is necessary for the tectonic plates.

Is the floor of the ocean the plate, and then the continents float on top of it?

Wikipedia - Plate Tectonics

In this case, there may be a relatively fine distinction where all 3 layers can co-exist. 

Our moon may be too cold with too thick of a crust, and not enough internal "geothermal" energy to have the plate/crust boundary.  And no liquid water.

Mars may also be too cold, although it certainly has had something forming ridges, valleys, and volcanoes in the past.
In fact, notes seem to indicate past tectonic activity on Mars. & here.  Could the Martian plates have fused to the crust?  There also isn't an ocean/continent boundary.

In a sense, Europa also has a floating crust (of ice), but perhaps too deep of an ocean to have true tectonic plates., but there will be more exploration of the moon in the future.  I don't believe Europa has continents per se.

Venus also seems to be lacking the Earth-like oceans which may be necessary for tectonic plates.

Offline TectonoGirl

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Re: Is Earth unique in having tectonic plates?
« Reply #2 on: 21/10/2013 18:49:29 »
Plate tectonics is a process which is unique to planet Earth as far as we know.  The exact rigidity, elasticity, and thickness of Earth’s lithosphere are key factors which make plate tectonics possible.  Other planets fall outside the narrow range of yield stress and water content required for plate tectonics. 

Venus is thought to have a rigid outer surface that does not conduct heat well enough so rather than cycling its plates through an underlying mantle; plates simply dive back under episodically.  Mars is at the opposite end of the spectrum with a crust that is too thick and strong to yield under the applied stresses (Regenauer-Lieb, 2006). 

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Re: Is Earth unique in having tectonic plates?
« Reply #2 on: 21/10/2013 18:49:29 »


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