Question

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

Answer 1

Answer:

Option (1)

Explanation:

In a divergent plate boundary, the two plates move away from one another. In an ocean basin, seafloor spreading takes place at the mid-oceanic ridge, and in the continental areas, rifting takes place and forms rift valley.

During the time of divergent motion of the plates, the magma rises upward with great force. Due to this, the lithosphere becomes thin, and there comes a point, when the pressure exceeds. This results in the eruption of magma at the seafloor. As the magma reaches the surface, there occurs the process of decompression, where the magma experiences a lesser amount of pressure by the overlying rocks. The magma then solidifies and eventually forms basaltic igneous rocks along this mid-oceanic ridge and these are the geologically youngest rocks.

thus, the correct answer is option (1).