Deciphering the magmatic evolution of the Hyblean Cretaceous volcanism (SE Sicily, Italy): New geochemical, isotopic and noble gas analyses

The coupling of helium isotopes in fluid inclusions with conventional geochemical data provided a new perspective on the volcanic processes that took place during the Cretaceous in southern Sicily. Our new investigations reveal that during two distinct volcanic phases in the Late Cretaceous, magmas formed from low degrees of partial melting of a heterogeneous mantle source characterized by spinel lherzolite and varying garnet content. The collected samples, including lava flows, dikes, and sills, exhibit a wide range of rock types, from picritic basalts to hawaiites. Two different magma types were identified: one displaying a bell-shaped pattern akin to ocean island basalts (OIB) and another with an irregular pattern marked by positive spikes in Nb, K, Pb, Sr, Zr, and Ti. Strontium and Neodymium isotope compositions are weakly radiogenic, while the Pb isotope systematics show strong radiogenic values (206Pb/204Pb = 19.64–20.42; 207Pb/204Pb = 15.61–15.70; 208Pb/204 Pb = 39.26–39.98), co...