The carbonatites of Mt. Vulture as a (re)source of rare earth elements.

Mt. Vulture volcano is situated at the easternmost border of the Italian Apennine compressive front. It is a composite volcano whose activity was both explosive and effusive from middle to upper Pleistocene. The final volcanic products have carbonatitic composition and represent the object of this study. In particular, two lava flows (upper and lower) and a dyke were sampled and analyzed. The mineralogical assemblage is similar in all samples: calcite, clino- and/or orthopyroxene, melilite, phlogopite, amphibole and ± plagioclase are the primary minerals, while apatite, opaque minerals, ± rutile and ± zircon are the accessory phases. The main difference between analyzed rocks are the amounts of primary calcite and plagioclase, the Ba contents and the (La/Yb)ch values, larger in the lower lava flow. In all samples, rare earth elements have very high concentrations and show high LREE/HREE fractionation that, through the R-mode factor analysis and PCA extraction method, has been attributed at different mineral phases.