Obsidian hydration is not effective on surfaces that are uneven due to gradual weathering caused by natural forces.
Finally the anomalous fading is estimated storing irradiated samples in dark at room temperature for few months and comparing the TL signal with the signal of samples immediately after irradiation.
After irradiation, a pre-heating is performed in oven at 150° C for 180 s to reduce the contribution of the TL signal coming from unstable traps.
All TL measurements are carried out by means of a TL2000-Ipses reader in nitrogen atmosphere using a 10°C/s heating rate.
The upper dating limit of quartz dose not exceed 100,000 years. Mejdahl, Risoe National Laboratory, DK-4000 Roskilde, Denmark.
The uncertainty of the zero point in this time span introduces a substantial error in age estimates.
At now fine grains method is applied in our laboratory, but in future also the quartz inclusion grains procedure will be implemented.