Global pulsations of intraplate magmatism through the Cenozoic

A review of Earth9s most significant 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 Pacific, 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 fluctuations in core-mantle interaction, involving periodic heating of Earth9s core and subsequent increases in global plume activity from the edges of the lower-mantle anomalies.