Description of fundamental paramagnetic defects observed in a raw clay: an index for the ESR dating of ancient ceramics

Two paramagnetic defects, the peroxy and E' centers, were observed in a raw clay by using electronic paramagnetic resonance. The intense line, due to iron oxides, observed in the ESR spectrum of the clay, could to a great extent be eliminated. As a result the emergence of signals was readily permitted. The latter, associated with silicon, are localised either in the quartz contained in raw clay or in the clay matrix. Corrected by a thermal effect and sensitive to the radioactive radiation they could be used for the ESR dating of ancient ceramics. (C) Academie des sciences/Elsevier, Paris.