Lead Isotope composition and origin of the quaternary lavas of Elbrus Volcano, the Greater Caucasus: High-precision MC-ICP-MS data

A systematic study of Pb isotope composition was carried out for Elbrus Volcano, one of the Europe's largest volcanoes, using high-precision method of multi-collector inductively coupled plasma mass spectrometry. The measurement error of Pb isotope ratios was estimated from the results of replicate analyses of international BCR-1 and AGV-1 standards as +/- 0.03% (+/- 2SD). The study of a representative collection showed that dacites of all three phases of the Elbrus eruptive activity are characterized by relatively small-scale variations of Pb isotope composition: Pb-206/Pb-204 18.621-18.670, Pb-207/Pb-204 15.636-15.659, and Pb-208/Pb-204 38.762-38.845. New Pb isotope geochemical characteristics in combination with existing Sr-Nd data indicate that the parental magmas of Elbrus are of mixed mantle-crust origin. They were formed by interaction of mantle-derived melts with continental crust of the Greater Caucasus during continental collision between the Eurasian, Arabian, Turkish, and Iranian plates. DOI: 10.1134/S0869591113010037