Hotspots and Mantle Plumes

Abstract

Seismic images under 62 possible hotspots are reviewed for understanding the origin of hotspots and mantle plumes. Plume-like, continuous low-velocity anomalies are visible beneath Hawaii, Tahiti, Louisville, Iceland, Cape Verde, Reunion, Kerguelen, Amsterdam, Afar, Eifel, Hainan, Yellowstone and Cobb hotspots, suggesting that they may be 13 whole-mantle plumes originating from the core-mantle boundary. These plumes exhibit tilted images, suggesting that plumes are not fixed in the mantle but can be deflected by the mantle flow. Upper-mantle plumes seem to exist beneath Cameroon, Easter, Azores, Vema, East Australia and Erebus hotspots. A mid-mantle plume may exist under the San Felix hotspot. Active intraplate volcanoes in Northeast Asia and Southwest China are caused by hot and wet upwelling flows in the big mantle wedge above the stagnant slab in the mantle transition zone. Although low-velocity zones appear at some depth under other hotspots, their plume features are not clear. The complex images under hotspots reflect strong lateral variations in temperature, viscosity and possibly composition of the mantle, which control the generation and ascent of mantle plumes and the flow pattern of mantle convection.