Mantle plumes origin

Stein and Hofmann (1994) sought to resolve this problem by proposing that, over geological time, there have been periodic influxes of lower mantle material into the upper mantle to "recharge it" with the necessary trace elements to make the continental crust. These periodic influxes were thought to have taken the form of mantle plumes originating in the lower mantle, and some workers see this model as support for a plume model of continental growth. 

The variable isotopic compositions (especially for Pb) reveal geochemi-cally heterogeneous sources. The origin of this heterogeneity is debated and may derive either from shallow mantle processes, such as variable me-tasomatic modifications of the lithosphere by asthenospheric melts, or from mixing between a deep-mantle plume and asthenosphere-lithosphere material. Etna and Ustica show some trace element and isotopic characteristics (e.g. Rb/Nb, Ce/Pb, and boron isotopes), indicative of a contribution from subduction-derived components. 

Nie, A., and Xie, H. (2006). A study on Emei mantle plume activity and the origin of high-As coal in southwestern Guizhou Province. Chinese J. Geochem. 25(3), 238—244. 

The origin of FOZO-C-PHEM-PREMA, simply referred to as FOZO hereafter, may be of farther-reaching consequence than any of the other isotope flavors, if the inference of (Hart et al., 1992) is correct, namely, that it represents material from the lower mantle that is present as a mixing component in aU deep-mantle plumes. The evidence for this is that samples from many individual OIB associations appear to form binary mixing arrays that radiate from this focal zone composition in various directions toward HIMU, EM-1, or EM-2. These relationships are shown in Figure 16. The FOZO composition is similar, but not identical, to DMM represented by MORB. It is... 

Niu Y., Collerson K., Batiza R., Wendt I., and Regelous M. (1999) Origin of enriched-type mid-ocean ridge basalt at ridges far from mantle plumes, the East Pacific Rise at n°2tl N. J. Geophys. Res. 104, 7067-7087. 

Zhao D. (2001) Seismic structure and origin of hotspots and mantle plumes. Earth Planet. Sci. Lett. 192, 251-265. 

Trieloff M., Kunz J., and Allegre C. J. (2002) Noble gas systematics of the Reunion mantle plume source and the origin of primordial noble gases in Earth s mantle. Earth Planet. Sci. Lett. 200, 297-313. 

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