A
mantle plume is a mechanism proposed in 1971 to explain volcanic regions of the earth that were not thought to be explicable by the then-new theory of
plate tectonics. Some such volcanic regions lie far from
tectonic plate boundaries, for example, Hawaii. Others represent unusually large-volume volcanism, whether on plate boundaries, e.g. Iceland, or
basalt floods such as the
Deccan or
Siberian traps.