Abstract
In southern Italy, there are several active volcanoes which occur in diverse geotectonic settings. Isotope determinations on coexisting minerals and whole-rocks from zero-age lavas from Vesuvius, Etna and Stromboli reveal an isotope equilibrium for Sr isotopes1 but not for Th (ref. 2). Analyses for Pb in the same samples also reveal differences in isotope composition, and in all cases the phenocrysts are less radiogenic than the whole-rocks. We argue here that the Pb and Th isotope composition of the magmas changed during and after fractional crystallization, possibly by crustal assimilation or by addition of mantle-derived fluids and that whole-rock Pb isotope data are not representative of the magma sources.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
