What is the main source of downward convection<span> flow in the mantle called? The downward sliding characteristic of ridge-push is the result of what? </span>What causes<span> the </span>thermal convection that drives plate motion<span>? Is it the downward arm of convective flow in the mantle?
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</span>The heat driving<span> mantle </span>convection<span> has three sources. "Primordial" </span>heat<span> (left over from the accretion and differentiation that led to the formation of Earth's core) contributes 20 to 50% of the </span>heat<span>. ... Mantle </span>convection<span> is the main mechanism by which this </span>heat<span> escapes from the interior of Earth. </span> Hope this helped
