Aspects of thermoluminescence (TL) of quartz from metamorphic rocks of the Peloponnese (Greece) and its potential for geothermometry and thermochronometry

Abstract

This pilot study explores the suitability of thermoluminescence (TL) of quartzites from exhumed metamorphic rocks of the Peloponnese (Greece) for thermometry and thermochronometry. Specifically, four quartz samples with very low radioelement content were extracted from large quartz lumps exposed at the surface of extensive quartzite rocks that make up the metamoprhic core of the central and southern Peloponnese The samples were submitted to a series of experiments and methods of analysis involving the sensitization of the 110 °C TL peak, fractional glow (via initial rise), TL-signal deconvolution, and characterization of signal response to large doses. The sensitization of the 110 °C TL trap was used to monitor the peak metamoprhic temperature of the quartzites. This is a novelty employed for the first time in this work. The sensitization of the 110 °C TL trap points to peak metamorphic temperatures which seem to be in agreement with independent thermometric data specific to these rocks. TL deconvolution analysis returned at least three traps which exhibit variable geological stabilities (lifetimes) but high saturation levels. Our studies demonstrate that TL from these rocks has the potential to be used for both thermometry and thermochronometry. Nevertheless, the very low dose rates associated with these quartzes qualify the here estimated equivalent doses for the estimation of maximum cooling ages only at this stage.