Large numbers of osmium alloy grains are analysed to quantify the distribution of ages at which melt was extracted from the Earth's mantle. It is found that the ages are not evenly distributed but cluster in distinct periods, around 1.2, 1.9 and 2.7 billion years, coincident with peaks in the ages of continental crust, lending strong support to pulsed models of continental growth via large-scale mantle melting events.
- D. G. Pearson
- S. W. Parman
- G. M. Nowell