Investigation of the thermal stability of 210°C TL peak of quartz and dating the components of terrazzo from the monastery church of Tegernsee

Abstract

The lifetime of the thermoluminescence (TL) peak of quartz observed at 210°C using 5°C/s heating rate is assessed using well-dated thermally isolated bricks from a monastery and exposed bricks from warmer climatic zones by comparing the absorbed dose obtained using the 210°C TL peak with those obtained from 310°C TL peak. The lifetimes of the 210°C TL peak calculated for samples collected from thermally isolated excavations and exposed buildings are found to be clusted around 8000–10000 and 600–800 years, respectively. The results proved that 210°C TL peak could be used for dating of samples younger than 1000 years without thermal correction if the samples are thermally isolated from their environment. TL ages are obtained using quartz, polyminerals from brick pieces as well as flint splinters, and other quartz inclusions extracted from the mortar of the terrazzo floor of the monastery church. The measured TL ages and the consistency of the results are discussed. The fine grains in the mortar, which contained calcite/aragonite, could not be dated using thermoluminescence due to presence of a very strong non-radiation induced TL glow.