Electron paramagnetic resonance of perlites from the Eastern Rhodopes, Bulgaria

Pages: 
pp. 53-60
University Paris VI, Laboratory "Mineralogy and Crystallography", Paris 75230 Cedex 05
Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Sofia 1113
Geological Institute "Strashimir Dimitrov", Bulgarian Academy of Sciences, Sofia 1113
Geological Institute "Strashimir Dimitrov", Bulgarian Academy of Sciences, Sofia 1113
Abstract: 

Four main types of signals have been fixed in the EPR-spectra of the studied perlites: structural Fe3+ with g = 4.3, iron-bearing microphases with a. broad signal at 8 = 3.2–2.1, Mn2+ with a six-component signal and a sensitive to irradiation electron center of the E1’ type with g = 1.999. Combinations of two or more of the above mentioned centers have been presented. Dependences have been established between the different colour varieties of perlites and the type and concentration of electron-hole defects: for Fe3+ high values have been obtained for the pale-coloured varieties and low values for the dark varieties with an absence among the reddish brown varieties; Mn2+ has been characteristic for some of the pale-coloured varieties and the radiation sensitive center has been observed in the reddish brown varieties. The content of magnetoconcentrated iron microphases does not influence the colour of the perlites.

VOLUME 18 (5)/October 1988

Higher institute for Mining and Geology, 1156 Sofia

University Paris VI, Laboratory "Mineralogy and Crystallography", Paris 75230 Cedex 05
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Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Sofia 1113
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Geological Institute "Strashimir Dimitrov", Bulgarian Academy of Sciences, Sofia 1113
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Geological Institute "Strashimir Dimitrov", Bulgarian Academy of Sciences, Sofia 1113

Sofia University "St. Kliment Ohridski" 15 Tsar Osvoboditel Blvd., 1504 Sofia, Bulgaria
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Sofia University "St. Kliment Ohridski" 15 Tsar Osvoboditel Blvd., 1504 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Геологический институт Болгарской академии наук, 1113 София

Геологический институт, БАН, 1113 София
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Геологический институт, БАН, 1113 София