Plates of the Crust Question?

Question

Is Convection the process believed to drive the movement of the plates of the crust???
Someone said it was, I'm not sure if it is.
Is it?
Thanks!

Answer 1

Hi Bri!

Well, no, it isn't.

Many people think that, but the cause remains controversial.

The most likely driving force is something akin to the principle of the siphon. Ocean crust, which gets thicker and heavier with age, sinks at plate boundaries, and this sinking drags the rest of the ocean crust with it.

Rock rising from beneath the earth was responsible for the first upwelling of oceanic crust, but the sea-floor conveyor is kept running by the effect of old, heavy crust sinking ("subduction" is the geological term) in places like the west coast of the Americas.

By the way, this principle only applies to the sea floor, not the continents. The earth's land masses are too light to be dragged down in this way. Continents float on the surrounding heavy rock, which is why the sea floor disappears, but the continents migrate endlessly across the earth in what is known as Continental Drift.

Answer 2

What Anne Marie was talking about is the Slab Pull Theory, and it has some proponents to it among geoscientists. Most geoscientists go along with Mantle Convection as the driving force for Plate Tectonics. Be aware that just like you are not sure, geoscientists are not sure. Slab Pull has problems with it (and I can't remember what they are), just like Mantle Convection has problems. No theory is 100% perfect.

Answer 3

that's the theory, just like gravity, they accept it until someone can prove something better. Theory has always been plates can only move slowly, that's why that ten mile patch of ancient green rock on the Mid Atlantic ridge has geologists so interested.