Why is so much mafic magma erupted along mid-ocean ridges?
A)Basaltic mantle under the ridge is hot enough to completely melt if seawater is added.
B)Lowered pressures decrease the temperatures at which mafic magma can partially melt from massive, extensive, rising plumes of mantle peridotite.
C)The subducting, oceanic slab sinks so deep that eventually it melts, producing massive quantities of mafic magma.
D)The mantle beneath the ridges is enriched in thorium, uranium, and potassium, causing strong heating due to energy from radioactive decay.

Question

Quizplus · Accepted Answer

Mid-ocean ridges are marked by elevated temperatures due to the influx of hot mantle material. However, the pressure at these depths is much lower than at shallower depths, resulting in a lowering of the melting point of the mantle rocks, such as peridotite, which are rich in mafic minerals. This results in partial melting of the mantle, which generates mafic magma.

Why Is So Much Mafic Magma Erupted Along Mid-Ocean Ridges