ABSTRACT
Results of study of Rb-Sr isotope systems are increasingly used in geochemical studies and systematics of igneous rocks differing in composition and genesis. The first data on these systems in rocks from mafic-ultramafic massifs of the East Sakhalin ophiolite association were obtained for samples of ultramafic rocks and gabbroids from the Berezovka and, partly, other massifs [Kiseleva et al., 2010; Lesnov et al., 2010b]. These studies were carried out in the laboratory of the Analytical Center of the Sobolev Institute of Geology and Mineralogy by the standard technique, including (1) acid digestion of weighted rock specimens, (2) separation of Rb and Sr by ion exchange chromatography on Dowex AG 50WX8 resin (200-400 mesh) with 2 N HCl as an eluent, and (3) measurement of Rb and Sr isotope ratios with an MI 1201T solid-phase thermal-ionization mass spectrometer in double-ribbon mode with one-collector recording. The accuracy of measurement of the 87Sr/86Sr ratios was controlled by parallel measurements of the VNIIM (Mendeleyev Institute for Metrology) (0.70800 ± 10, specification; 0.70810 ± 10, measurement) and ISG-1 (0.71731 ± 10, specification; 0.71727 ± 4, measurement) geochemical standards.
