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

GÓMEZ, J.E.; BORETTO G.; GORDILLO S.

Advances in Geomorphology and Quaternary Studies in Argentina

SPRINGER

Año: 2021; p. 337 - 353

We have performed electron paramagnetic resonance (EPR) experiments on a set of bivalves (Ameghinomya antiqua) collected from the Quaternary marine deposits of the Argentinean Patagonian coast. We have analyzed the EPR signal of these shells to carry out an exploratory study of the EPR absorption lines. We have observed absorptions associated to SO2¯ radicals (g = 2.0057 and g = 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 increases according to the estimated age of the bivalve. The microwave power dependence of the spectra reveals that for this type of shells it is desirable to work at high powers 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 rotating CO2¯ radical.