GIGC-IPE, Université Libre de Bruxelles (CP 160/02), 50 av. Roosevelt, B-1050 Brussels, Belgium (Aspirant du F.R.S.-FNRS); UMR-CNRS 6112, LPGN, Université de Nantes, 2 rue de la Houssinière, BP 92208, 44322 Nantes Cedex 3, France
Faculty of Geology and Geography, Department of Mineralogy, Petrology and Economic Geology, Sofia University “St Kliment Ohridski”, 15 Tsar Osvoboditel Blvd, 1504 Sofia