Liquid line of descent of a basanitic liquid at 1.5 Gpa: constraints on the formation of metasomatic veins

Origins of cratonic mantle discontinuities: A view from petrology, geochemistry and thermodynamic models

“…29 settings (Pilet et al, 2010(Pilet et al, , 2011Grant et al, 2014). The composition of most kimberlites demands that they interacted with (or even formed in) metasomatised refractory cratonic mantle sources (Becker and Le Roex, 2006;Sokol et al, 2014) and that, conversely, the cratonic mantle is modified by their passage.…”

Petrogenesis of Cenozoic volcanic rocks in the NW sector of the Gharyan volcanic field, Libya

“…In conclusion, the HIMU-OIB-like sodic alkaline mafic compositions (basanites s.l.) commonly found in intraplate settings can be considered both as partial melting products of amphibole-rich metasomatic levels in the lithospheric mantle (e.g., Pilet et al, 2010) and as the origin of the same amphibole-rich metasomatic levels (e.g., Green et al, 2010;Adam and Green, 2011). Both hypotheses are compatible with the same type of petrogenetic process.…”

“…Differences in the trace element partition coefficients between the various minerals can lead to a formation of a residual melt with a composition partially to completely different from the original E-MORB liquid, reaching basanitic, HIMU-OIB-like characteristics (Adam and Green, 2011). If sufficiently H 2 O-rich, this evolved melt may stabilize amphibole during further cooling in the shallow melting, leading to the formation of amphibole-rich metasomatic levels studied by Pilet et al (2010Pilet et al ( , 2011. In conclusion, the HIMU-OIB-like sodic alkaline mafic compositions (basanites s.l.)…”

“…On these grounds, Pilet et al (2008Pilet et al ( , 2010Pilet et al ( , 2011 proposed an alternative origin for the sodic alkaline rocks, hypothesizing that the most peculiar incompatible element features typical of sodic alkaline mafic and ultrabasicbasic rocks (e.g., basanitic s.l.) can be generated after partial melting of an amphibole-bearing mantle source.…”

“…the limits of this approach, the provenance of the partial melt is supposed at the base of the lithospheric mantle because of the coexistence of spinel and garnet, and the presence of amphibole in the source (e.g., le Roex et al, 2001;Melluso and Morra, 2000;Melluso et al, 2007). The spinel-garnet transition occurs at about 70-90 km depth under average continental geotherms, close to the average petrological lithospheric mantle sole, while the amphibole stability limit is around 2.5-3.5 GPa (~90-110 km in depth; Green et al, 2010;Pilet et al, 2010, and references therein).…”