At mid-ocean ridges, as two plates diverge:
A) solid mantle in the asthenosphere rises toward the surface and begins to melt due to decompression
B) solid mantle in the asthenosphere rises toward the surface and begins to melt due to the addition of heat
C) liquid mantle in the asthenosphere rises toward the surface

Question

Quizplus · Accepted Answer

At mid-ocean ridges, solid mantle material from the asthenosphere rises toward the surface due to the divergence of tectonic plates. As it rises, the pressure decreases, leading to decompression melting, not because of the addition of heat or because the mantle is initially in a liquid state.

At Mid-Ocean Ridges, as Two Plates Diverge