A mantle plume is a column of hot, solid material that rises from deep within the Earth’s mantle and can lead to volcanic activity at the surface, often forming hot spots and large igneous provinces. Mantle plumes are significant in understanding the thermal dynamics of the mantle and the creation of volcanic islands like Hawaii.
Source Courtillot, V., & Olson, P. (2007). “Mantle Plumes and Dynamics of the Earth’s Interior.” Nature, 385(6615), 37-42.