Which statement about mantle plumes and surface volcanism is correct?

• A. They do not affect surface volcanism.
• B. They only occur at subduction zones.
• C. They are explained by tectonic plate motion at plate boundaries only.
• D. They can create hotspot volcanism and volcanic chains as plates move over upwelling material.

Answer: (D)

Mantle plumes are upwellings of hot mantle material that can melt and feed volcanism at the surface even away from plate boundaries. When a tectonic plate moves over a relatively fixed plume, magma erupts at the surface as a series of volcanoes that form a chain as the plate continues to drift over the upwelling. This explains hotspot volcanism and why volcanic chains develop as a plate travels over the plume. The Hawaii-Emperor chain is the classic example of this process, showing how a stationary hotspot can create a line of volcanoes as the plate moves over it. In contrast, statements that say there’s no surface volcanism, that it only happens at subduction zones, or that volcanism is explained solely by boundary motion don’t capture this intraplate hotspot mechanism and the resulting volcanic tracks.