Institute of Geodynamics, Romanian Academy 19-21, Jean-Luis Calderon str., RO-020032 Bucharest, Romania; Sapienţia University, Dept. of Environmental Sciences, Matei Corvin str., 4, RO-400112 Cluj-Napoca, Romania
Faculty of Geology and Geography, Department of Mineralogy, Petrology and Economic Geology, Sofia University “St Kliment Ohridski”, 15 Tsar Osvoboditel Blvd, 1504 Sofia