GEOCHEMICAL AND SR-ISOTOPE DATA ON HISTORIC LAVAS OF MOUNT ETNA

The concentration of trace elements (La, Nb, Rb, Zr, Sr, Ni, Co, Cr an d Cu) have been determined in 46 samples from 14 historical eruptions of Mt. Etna (1444 to 1983) as well as their Sr-isotope compositions. T he measured values show significant variations that are explained in t erms of magma generation, differentiation, and mixing processes. The c ontamination by diffusion of volatile-enriched fluids, suggested by ea rlier authors, might be confirmed here with reference to Rb behaviour, and the same process is also invoked in order to explain variation of Sr-isotope compositions. Nevertheless, the hypothesis of source heter ogeneity, stated by other authors, cannot be ruled out.