William P. Leeman, Derek L. Schutt, Scott S. Hughes Journal of Volcanology and Geothermal Research, 2009 188:57-67
Abstract: Basaltic magmatism associated with the Yellowstone hotspot has been widely attributed to upwelling of a
mantle plume, yet the temporal and spatial distribution of these magmas and their compositional
characteristics are distinctive from oceanic hotspot magmatism. Fundamental questions concern the
influence of continental cratonic lithosphere in producing the differences, and the extent to which upper
plate processes contribute to magma production. To better understand scenarios of melt generation, P–T
conditions are estimated for segregation of primitive Snake River Plain (SRP) basalts from the mantle.
Combined with analysis of trace element and seismic constraints, we conclude from this that (1) melt
production was concentrated at depths between roughly 70–100 km, (2) mantle temperature was only
slightly higher than ambient conditions with a maximum potential temperature of 1450 °C, and (3) the
mantle source was relatively fertile (Mg#<90). These results suggest that the seismically imaged plume
below Yellowstone is significantly cooler than upwellings beneath Hawaii, Iceland and many other oceanic
“hotspots”. Our findings, in combination with other geochemical and geodynamic considerations, are
permissive of magma generation within the ancient lithospheric mantle keel associated with the Wyoming
craton. Plume contributions, while not excluded, involve physical and geochemical implications that suggest
they are subordinate.