Reports on tests conducted to show whether tooth enamel might be altered during burial by focusing on the carbonate content and electron spin resonance (ESR) signals used for dating. Since oxidized carbon atoms (CO₂ or CO₃ moieties) in the apatite lattice give rise to the ESR dating signal as a function of absorbed radiation dose, inward or outward carbonate mobility would induce changes in the radiation sensitivity of the ESR dating signal. Manometry and Fourier transform infrared spectroscopy were used to study carbonate in 11 fossil and five modern tooth enamels from horse, cow, hippopotamus, rhinoceros, and mammoth. Ungulate tooth enamel exhibits a narrow range of both carbonate content (4.5 to 5.1 weight %) and ESR signal intensity (at 300 Gy radiation dose). These characteristics are true both for modern and most fossil samples ranging in age up to several hundred thousand years. The authors found evidence for possible diagenesis for only two samples, consisting of fragments of enamel that exhibited anomalous high and low carbonate contents (and ESR signal sizes).