Petrological characterization of the mantle source of Mediterranean lamproites: Indications from major and trace elements of phlogopite

Lamproites are among the most enigmatic mantle generated melts, and are typically abundant in phlogopite. We investigated the major and trace element chemistry of phlogopite crystals from Mediterranean lamproite occurrences in Spain, Serbia and Turkey. The most primitive lamproite samples were selected in order to evaluate the generation of the different phlogopite populations in their distinct mantle setting(s).Phlogopite hosted in Mediterranean lamproites can be grouped into different compositional arrays on the basis of their major element chemistry using Al2O3, FeOT and TiO2 concentrations. Contents of Cr, F and presumably Ti allow discrimination of the macrocrysts into phlogopite phenocrysts, which are liquidus and near-liquidus phases, and mantle xenocrysts. Further distinction among different populations of mantle-derived phlogopite can be achieved, considering trace element and isotopic ratios. The latter also distinguish between crustal and asthenospheric imprints on the source of the lamproitic parental melt.

► Trace element geochemistry of lamproitic micas is a reliable petrogenetic indicator. ► It traces contribution of crustal vs asthenospheric material to the mantle source. ► Trace element ratios of phlogopite denote different genetical populations of micas. ► Resorption of mantle micas is a major mechanism for genesis of ultrapotassic rocks. ► Lamproitic phlogopite records source characteristics from resorbed mantle micas.