Global pulsations of intraplate magmatism through the Cenozoic

Abstract

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 fluctuations 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. © 2010 Geological Society of America.