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As mantle plumes begin in the core and move towards the crust, I would have thought that the heat in the mantle plume would disperse to the surrounding mantle, and the plume would cease to exist by the time it reaches the crust, a large distance away.

So how is the mantle plume able to survive with such a localized trajectory on its way from the core of Earth to the crust?

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    $\begingroup$ Can you provide a reference for the claim that mantle plumes travel in a straight line? $\endgroup$ – naught101 Apr 20 '14 at 13:09
  • $\begingroup$ @naught101, they aren't exactly thought to be straight, but they usually form a column like structure in the mantle, which can form into a mushroom type shape as it nears the crust. Often the mantle underlying tectonic boundaries can distort the trajectory of a mantle plume. What I'm more interested in however is how this hot stream of mantle can remain so localized as it traverses (possibly not in a straight fashion) such a large distance from the core to the crust. I have edited the question for clarity. $\endgroup$ – Kenshin Apr 20 '14 at 13:24
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    $\begingroup$ @naught101, also note that the trajectory of mantle plumes isn't exactly random either, as a coherent trajectory of the plumes is what is used to explain why you can have lines of volcanoes in the middle of a tectonic plate. Half the value in the theory is that the plumes are theorized to occur at defined points on the core-mantle boundary that do not change with time, and if the trajectories were random, then it need not matter where the plume originated in the mantle-core boundary. Therefore the theory must assume that the trajectories move in some consistent manner from the core to crust $\endgroup$ – Kenshin Apr 20 '14 at 13:27
  • $\begingroup$ that is wrong mew. They do change with time, just over long time scales. $\endgroup$ – Neo Apr 20 '14 at 17:37
  • $\begingroup$ @mew, your question title still says "straight line". Also, it would really help your questions stay open if you put at least some of the effort that you put into response comments like these into the question itself, instead. $\endgroup$ – naught101 Apr 21 '14 at 1:02
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The high values obtained when estimating the Rayleigh number for the mantle indicates that convection there is vigorous, and that convection is responsible for almost all the heat transported from the deep interior to the surface. Similar systems set up in the laboratory can develop 'plume-like' patterns of convective flow, and so mantle plumes are a physically plausible model of mantle convection too.

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    $\begingroup$ Peter Olson, Christopher Kincaid, and many others have done numerical and analog experiments that support this statement. $\endgroup$ – Neo Apr 21 '14 at 20:56

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