Potassic and ultrapotassic magmatism in the circum-Tyrrhenian region: Significance of carbonated pelitic vs. pelitic sediment recycling at destructive plate margins

摘要: Abstract The central-western Mediterranean is one of the most important areas on Earth for studying subduction-related potassic and ultrapotassic magmatism. In circum-Tyrrhenian area leucite-free (i.e., lamproite) leucite-bearing kamafugite, leucitite, plagioleucitite) rocks have been emplaced are associated with shoshonites high-K calc-alkaline volcanic rocks. Four different magmatic provinces recognised from this area. Eastward then south-eastward migration magmatism time occurred following roll-back subducting plate. Leucite-free silica-rich lamproites restricted to early stages magmatism, Present day activity Neapolitan district where variable geochemical isotopic characteristics occur. Ultrapotassic strongly enriched in incompatible trace elements fractionation Ta, Nb, Ti respect Th large ion lithophile elements. Mafic also variably radiogenic Sr Pb unradiogenic Nd. main signatures result sediment recycling within upper mantle via subduction. Selected element ratios suggest that high temperatures required generate sediment-derived melts. Recycling carbonated pelites play an role Roman province controlling genesis magmas. Large volumes metasomatic components predicted be accommodated a vein network sub-continental lithospheric mantle. Partial melting pure mineralogy likely magmas either lamproitic or kamafugitic nature. Over time, increased interaction between lithology surrounding dilutes alkaline component producing calc–alkaline addition further shortly before magma generation explain composition district. last phases evolution, within-plate appears south-eastern Italy. This evident at Vulture volcano, Lucanian Magmatic (SE Italy).