Electron Paramagnetic Resonance as a Dating Tool for Determining the Age of Marine Mollusk Shells.

GÓMEZ, JAVIER; BORETTO, G; GORDILLO, SANDRA

Advances in Geomorphology and Quaternary Studies in Argentina

Springer

Año: 2021; p. 337 - 353

We have performed electron paramagnetic resonance (EPR) experimentson a set of bivalves (Ameghinomya antiqua) collected from the Quaternarymarine deposits of the Argentinean Patagonian coast. We have analyzed the EPRsignal of these shells to carry out an exploratory study of the EPR absorptionlines.We have observed absorptions associated to SO2¯ radicals (g = 2.0057 andg = 2.0031) and of CO2¯ (isotropic at g = 2.0006 and anisotropic with gx =2.0017, gy = 1.9975 and gz = 2.0033). The intensity of the EPR signal increasesaccording to the estimated age of the bivalve. The microwave power dependenceof the spectra reveals that for this type of shells it is desirable to work at highpowers in order to obtain a well-defined radiation sensitive signal at g = 2.0006.According to the literature, this absorption can be associated to a freely rotatingCO2¯ radical.