Uranium mantle evolution

This reflects both the presence of less parental and the more efficient recycling of U into the mantle under the more oxidizing atmospheric conditions that have prevailed since 2Gra. This major change in the behaviour of uranium has been reafiirmed in discussions of Th U—Nb systematics (Collerson Kamber 1999) and Th/U mantle evolution (Elliott et al. 1999). 

O Hara MJ (1968) The bearing of phase equilibria studies in synthetic and natural systems on the origin and evolution of basic and ultrabasic rocks. Earth Sci Rev 4 69-133 O Nions RK, McKenzie D (1993) Estimates of mantle thorium/uranium ratios from Th, U and Pb isotope abundances in basaltic melts. Phil Trans Royal Soc 342 65-77 Oversby V, Gast PW (1968) Lead isotope compositions and uranium decay series disequilibrium in reeent volcanic rocks. Earth Planet Sci Lett 5 199-206... 

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