Question

which theory of plate movement involves magma rising all the way from the lower mantle to spread apart plates?
a. hot plumes
b. slab - pull
c. convection current model
d. slab - push

Explanation:

• Hot plumes: These are columns of hot, buoyant material that rise from deep within the mantle (not necessarily from the lower mantle to spread plates in the way described in the question).
• Slab - pull: This is a mechanism where the dense, subducting oceanic plate (slab) pulls the rest of the tectonic plate along. It is not related to magma rising from the lower mantle to spread plates.
• Convection current model: In the traditional convection current model (although there are some refinements now), it was thought that convection currents in the mantle, with magma (hotter, less - dense material) rising from the mantle (in some early views, even from the lower mantle) and spreading apart at mid - ocean ridges, creating new crust and moving plates apart.
• Slab - push: This is a force exerted by the elevated mid - ocean ridge pushing the tectonic plate away from the ridge. It is not about magma rising from the lower mantle.

Answer:

C. Convection current model