Chemical diffusion of Pb was measured in natural calcite under anhydrous conditions. The source of diffusants for the diffusion experiments was PbO powder. Rutherford back-scattering spectroscopy was used to measure diffusion profiles. The Arrhenius relationship at 440 to 650:

D(m2/s) = 5.8 x 10-15 exp[-117(kJ/mol)/RT]

D.J.Cherniak: Geochimica et Cosmochimica Acta, 1997, 61[19], 4173-9