The pillow basalts in the photo below most likely formed ____________.
A) on dry land at a continental hotspot
B) underwater at a subduction zone
C) on dry land at a continental rift
D) underwater at a mid-ocean ridge

Question

The pillow basalts in the photo below most likely formed ____________. 
A) on dry land at a continental hotspot 
B) underwater at a subduction zone 
C) on dry land at a continental rift 
D) underwater at a mid-ocean ridge

Quizplus · Accepted Answer

The pillow basalts in the photo are a characteristic feature of volcanic rocks that are formed when magma is extruded onto the ocean floor at mid-ocean ridges. The rapid cooling of the magma in contact with cold water causes it to solidify to form pillow-shaped structures. Therefore, the most likely explanation is that these pillow basalts formed underwater at a mid-ocean ridge.

The Pillow Basalts in the Photo Below Most Likely Formed