Abstract In the present work some results of terrestrial and fresh-water shell investigations are reported. It is shown that the energy parameters of the g=2.0012 center in terrestrial shells studied (E=1.62±0.01 eV, s=(2.3±0.4)× 10 3 s −1, τ=3.2 × 10 8 y at 5°C) essentially differ from those in marine shells (E=1.52±0.01 eV, s=8 × 10 13 s −1, τ=1.14 × 10 6 y at 5°C). There are some differences in other paleodosimetric properties as well (e.g., sensitivity to irradiation, saturation dose, fading, etc.). The shapes of main spectral peaks of shells and some other carbonates are also compared. Besides, problems connected with the g=2.0012 center concentration measurements are discussed.