Final answer:
The surface manifestation of a mantle plume is a hotspot, characterized by volcanic activity that can produce varying types of lava depending on the crust it emerges through.
Step-by-step explanation:
The surface manifestation of a mantle plume is best described as a hotspot. Mantle plumes originate from the core-mantle boundary, and as the lithosphere drifts over these plumes, it can cause melting and the creation of volcanic features. Hotspots can exist far from the edges of tectonic plates, meaning they don't rely on plate boundaries to form. Some prominent examples include the Yellowstone and Hawaiian hotspots.
Volcanoes that develop above hotspots can have different characteristics depending on the type of crust they emerge through, with oceanic crust typically producing basalts and continental crust producing a mix of basalts and rhyolites.