A mantle plume is a column of hot, solid material that rises from deep within the Earth's mantle. This upward movement occurs due to the heat generated by the Earth's core, causing the mantle material to become less dense and rise toward the surface. Mantle plumes can lead to volcanic activity when they reach the lithosphere, the rigid outer layer of the Earth. These plumes are often associated with volcanic hotspots, such as the one that created the Hawaiian Islands. Unlike tectonic plate boundaries, where most volcanic activity occurs, mantle plumes can produce volcanoes in the middle of tectonic plates. This phenomenon helps scientists understand the dynamics of the Earth's interior.