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Abstract

Hotspots are regions of intraplate volcanism or especially strong volcanism along plate boundaries, and many of them are likely caused by underlying mantle plumes – localized hot upwellings from deep inside the Earth. It is still uncertain, whether all plumes or just some of them rise from the lowermost mantle, and to what extent and where they entrain chemically different materials. Also, large uncertainties exist regarding their size. Some plumes (such as Hawaii) create linear hotspot tracks, as the plate moves over them and can therefore serve as reference frames for plate motions, whereas others (such as Iceland) show a more complicated distribution of volcanic rocks due to variable lithosphere thickness and plume-ridge interaction. Plumes may also weaken plate boundaries and hence influence plate motions. They may influence surface features such as ice sheets, and therefore climate, but we are just beginning to study and understand processes jointly involving solid earth, hydrosphere and atmosphere.