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

通过对不同遗传橄榄石种群（地幔异晶、斑晶、堆积橄榄石等）的原位氧同位素综合测定和原位主、次、微量元素测定，评价环地中海新生代造山、造空岩浆作用下地幔组分的身份和成因。橄榄石的原位同位素和元素组成将在相同的地点测定，以避免通过蚀变对大块岩石的真实组成进行低温伪造。此外，与熔岩相比，橄榄石代表了早期岩浆过程的档案，提供了较不均匀的熔融过程说明。氧同位素将指示烃源岩是否经历过交代作用，它将标志着来自大陆（18O富集）或蚀变的海洋地壳（变化，但通常是18O枯竭）。结合元素组成，该方法是区分和量化不同地球化学成分的有力工具，特别是用于跟踪环地中海新生代岩浆省源区的再循环地壳成分。这一首次应用于橄榄石的原位分析方法有望成为橄榄石研究的一个突破，并证实了橄榄石作为早期岩浆过程相关成岩指示物的应用。

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.