The lower-crustal section exposed in the Serre, southern Italy, consists mainly of Al-rich metasediments, which underwent granulite-facies metamorphism, partial melting and melt extraction. The paper considers the formation of melts in metapelites and metagreywackes. Leucosomes and host rocks have been studied to investigate the melting process. Biotite-rich and biotite-free melanosomes with scarce felsic components are present; the biotite-rich types are widespread in the upper part of the section and the two types may occur side by side in the lower part. Na-rich and K-rich leucosomes including residual phases are interspersed within the metasediments; on the whole they do not show geochemical signatures suggestive of magmatic fractionation. Leucotonalitic types prevail among the sampled leucosomes, which generally are rare earth element (REE) depleted with positive Eu anomalies whereas the host rocks are REE enriched with overall negative Eu anomalies. Melanosomes and migmatites show restitic chemistries. The precursor metagreywackes underwent depletion in Na₂O and enrichment in K₂O. The precursor metapelites document general depletion in Na₂O and they may be enriched or depleted in K₂O. All the characteristics of the migmatites and of their components reflect a two-stage melting: (1) H₂O-present melting, involving mainly plagioclase, and (2) dehydration melting of micas. All the metasediments underwent H₂O-present melting, forming mostly sodic melts which, owing to their removal from the source as fast as they formed, did not accumulate in such proportions as to allow migration and mostly remained within the lower-crustal metasediments; metapelites also underwent variable dehydration melting, depending on chemical features and physical conditions, forming larger volumes of mobile granitic melts, most of which migrated far from the source. Extractions of 57–66 vol. % of total melts (sodic + potassic) from the most residual metapelitic melanosomes and of about 27–44 vol. % of potassic melts from metapelitic migmatites have been calculated. Higher volumes of the extracted melts have been calculated for the metapelites of the lower part of the section; the most depleted metagreywackes underwent melt extraction of about 9–13 vol. %. The two-stage melting occurred during the prograde metamorphism and continued during the isothermal decompression.

The application of zircon dating to the reconstruction of orogenic systems is invaluable since time constraints of the geological evolution of orogens are crucial for the proposal of geodynamic and paleogeographic models. Zircon is one of the most promising accessory minerals in geochronology of crystalline basements because of its high-closure temperature. Moreover, U-Pb data of relict and recrystallized grains indicate the maximum sedimentation age as well as the timing of metamorphism in metasediments. In addition, the U-Pb ages of magmatic zircons constrain the timescale of magmatism. The Calabria–Peloritani terrane (CPT) represents a key area in the Southern Variscan Belt, whose reconstruction is still unresolved. Therefore, a review of literature zircon age data accompanied with new data from six samples of orthogneisses, paragneisses, amphibolites, and actinolite schists, helps to constrain the evolution of this Cadomian fragment, affected by metamorphic and magmatic Variscan events. A revisiting of the timing of the geological events from Paleo-proterozoic to Permian is revealed by comparing the internal textures of zircons and their U-Pb age clusters. The detected age peaks at 2500 Ma, 1600 Ma, and 1000 Ma in the CPT were related to a provenance from West and East Gondwana realms. A sedimentation age around 630 Ma emerges for the middle-deep crust terranes of the CPT, affected by Ediacaran (579–540 Ma) intrusions, accompanied by metamorphism dated at 556–509 Ma in the host metasediments. In the following, during Ordovician–Silurian extensional tectonics, the former Cadomian terranes were at least locally affected by fluid-assisted metamorphism (around 450 Ma) whereas the upper extensional basins that formed, were infilled by sediments along with interspersed volcanic to subvolcanic products. All these pre-Silurian terranes were involved in the subduction process of the Palaeotethys–Gondwana margin beneath Laurussia. The compressive phase began around 347 Ma, with under-thrusting of the formerly Gondwana substrate that was subjected to middle-high grade metamorphism, while the Ordovician–Silurian sediments were scraped off along the front of the Southern Variscan Belt and affected by low-grade metamorphism. Decompression of the whole Variscan orogenic system started around 320 Ma, together with uplifting of the chain and emplacement of widespread granitic intrusions which ended around 280 Ma and completed the Variscan orogenic cycle in the CPT.