Melting and melt movement in the Earth - Melt production rates in mantle plumes

I calculate the melt production rates for mantle plumes lying beneath oceanic lithosphere from the crustal thickening measured by using seismics and from the volume of the overlying ridge. Observed melt production rates are higher where the lithosphere is thinner, in accord with theoretical predictions of the processes of decompression melting in convective plumes. The productivity of mantle plumes, and in particular that of the Hawaiian plume, is shown to vary on timescales of a few tens of millions of years. This can be explained by variations in the temperature and flow rate of the plumes. The trace of the Reunion plume shows a marked drop in melt production over the 30 Ma following generation of the Deccan flood basalts, which reflects a decrease in the plume temperature from the transient abnormally hot conditions associated with initiation of the plume.