Petrogenetic significance of ocellar camptonite dykes in the Ditrău Alkaline Massif, Romania

Age-corrected 143Nd/144Nd ratios vary from 0.51258 to 0.51269. The high εNd values of + 4.0 to + 6.1 which are consistent with intra-plate composition, together with light rare earth element (LREE), large ion lithophile element (LILE) and high field strength element (HFSE) enrichment in the camptonites is ascribed to the formation of small melt batches of a metasomatised sub-lithospheric mantle source. The presence of an asthenospheric 'high μ' ocean island basalt (HIMU-OIB)-type mantle component in the source region has also been revealed. A 1-4% degree of partial melting of an enriched garnet lherzolite mantle source containing pargasitic amphibole followed by fractionation is inferred to have been involved in the generation of the camptonites. They are deduced to be parental melts to the Ditrău Alkaline Massif.