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Physics and Chemistry of Minerals

, Volume 30, Issue 1, pp 39–43 | Cite as

Identification and valuation of paramagnetic radicals in natural dolomites as an indicator of geological events

  • R. W. A. Franco
  • F. Pelegrini
  • A. M. Rossi
ORIGINAL PAPER

Abstract

 Geological sedimentary dolomite samples from the Superior Proterozoic are studied using electron paramagnetic resonance (EPR) spectroscopy. The complex spectra in the g=2.0 region is composed of Mn2+ lines and signals due to crystallization and radiation-induced defects. Measurements in microwave frequencies of 9.5 GHz (X-band) and 35 GHz (Q-band), and thermal and/or radiation treatments allowed identification of seven paramagnetic radicals in the g=2.0 region: (1) isotropic organic radical; (2) axial SO2; (3) axial PO20 or PO22−; (4) isotropic CO2; (5) axial CO2; (6) axial CO33−; (7) isotropic unknown line. The use of these paramagnetic centres as indicators of geological events is discussed.

Keywords Dolomite EPR Gamma radiation Defects 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2003

Authors and Affiliations

  • R. W. A. Franco
    • 1
  • F. Pelegrini
    • 1
  • A. M. Rossi
    • 2
  1. 1.Instituto de Física, Universidade Federal de Goiás, 74001-970, CP: 131, Goiânia, GO, Brazil E-mail: robertofrancobr@hotmail.comBR
  2. 2.Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150, 22290-180, Rio de Janeiro, RJ, BrazilBR

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