Using olivine as a probe into early igneous and mantle melting processes: combining in situ oxygen isotopes with minor and trace-element compositions of olivine from Circum-Mediterranean Cenozoic magmatic provinces

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The identity and origin of mantle components tapped by Circum-Mediterranean Cenozoic orogenic and anorogenic magmatism will be evaluated on the basis of comprehensive in situ oxygen isotope combined with in situ major, minor and trace element measurements on genetically different olivine populations (mantle xenocrysts, phenocrysts, cumulitic olivine etc). The in situ isotopic and elemental compositions of the olivines will be determined on identical spots circumventing low-temperature falsification of the genuine composition of the bulk rock by alteration. Moreover, olivine represents an archive of early magmatic processes offering less homogenized account of the melting process compared to lavas. Oxygen isotopes will indicate if a source rock experienced metasomatism and it will signalize derivation from continental (18O enrichment) or altered oceanic crust (variable, but often 18O depletion). In combination with elemental compositions, this approach represents a powerful tool to discriminate and quantify different geochemical components in particular to track recycled crustal components in the source of the Circum-Mediterranean Cenozoic magmatic province. It is expected that the suggested in situ analytical approach applied for the first time on olivine is a breakthrough in olivine research and substantiates the application of olivine as a relevant petrogenetic indicator for early magmatic processes.