Nephelinite–melilitite–carbonatite relationships: Evidence from Pleistocene–recent volcanism in northern Tanzania

摘要: Abstract The younger ( An integrated model involves carbonated olivine–nephelinite magma generated in the asthenosphere by melting of carbonate-bearing peridotite. Small amounts melt migrate rapidly and are extruded as olivine–nephelinites –melilitites. Larger pond lithosphere with which they react and, during variable periods stagnation, varying degrees olivine–pyroxene–spinel fractionation take place before upward migration now-differing batches. Variable residence time within, reaction with, variably enriched accounts for array between HIMU mantle end-members isotope mixing model.