Global pulsations of intraplate magmatism through the Cenozoic

A review of Earth's most signifi cant intraplate Cenozoic hotspots with regard to variations in magmatic productivity through time indicates periodicities with a dominant period of ~10 m.y. and a secondary period of ~5 m.y.It is unlikely that the observed global variations in magmatic productivity can be explained by differences in lithospheric thickness, intraplate stresses, and/or interaction with oceanic spreading ridges.The majority of hotspots are located near the edges of the lower-mantle low-velocity anomalies under Africa and the central Pacifi c, suggesting that hotspots are the surface expressions of mantle plumes originating from the deepest mantle.It is postulated that the apparent co-pulsations in magmatism result from global fl uctuations in core-mantle interaction, involving periodic heating of Earth's core and subsequent increases in global plume activity from the edges of the lower-mantle anomalies.