Petrology and evolution of the central Serre granitoids (southern Calabria - Italy)

Field, petrological, geochemical and Sr-Nd isotopic data presented on the Hercynian calc-alkaline granitoids from Central and Southern Serre, provide information about their origin and evolution. The granitoids are intruded into low- to medium-grade phyllites and paragneisses, and show gradational transition from border biotite ± amphibole granodiorites (BAG) to internal two-mica granites and granodiorites (BMG). The BAG and the BMG are mostly peraluminous with peraluminosity increasing with rock acidity. Rb-Sr biotite and white mica ages from the ABG and the BMG are consistent to each other and range between 289 ± 4 and 266 ± 3 Ma. The most primitive isotopic signatures found in the ABG agree well with those of basic to intermediate Hercynian intrusives from Calabria, considered as hybrid rocks of mantle-crust mixed origin. Thus, the precursors of the ABG and the BMG likely were mantle-derived magmas which initially underwent deep contamination in the lower crust. -from Authors