THE OLDEST VOLCANIC GLASS IN THE EARLY PALEOPROTEROZOIC BONINITE-TYPE LAVAS, KARELIAN CRATON: RESULTS OF INSTRUMENTAL INVESTIGATIONS Article Sharkov E.V., Trubkin N.V., Krasivskaya I.S., Bogatikov O.A., Mokhov A.V., Zolotykh E.B., Ladygin V.M., Chistyakov A.V., Evseeva K.A. Doklady Earth Sciences. Vol. 390. 2003. P. 580-584