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.
