ESR AND OSL THERMOCHRONOMETRY OF QUARTZ: ATTEMPTED CALIBRATION WITH THE (U-TH)/HE ISOTOPIC DATING METHOD

The potential of ESR analysis of quartz to determine the cooling histories of rapidly exhumed rocks was shown in a study of the Pliocene Eldzhurtinsky Granite of the Greater Caucasus by Grün et al. (1999). However, the apparent ESR ‘cooling ages' have never been tested against results from other, more widely applied thermochronologic techniques, such as (U-Th)/He in apatite. This study attempts to compare the data from the Grün et al. (1999) with an apatite (U-Th)/He age dataset from the Eldzhurtinsky Granite. The comparison of quartz ESR apparent ages to apatite (U-Th)/He ages is based on the similar thermal sensitivities of ‘closed system' behavior within each dating system with respect to the measurable protagonist particles (i.e. electrons in quartz and He nuclei in apatite, respectively) during natural radiogenic accumulation. In both cases ‘closed system' behavior is restricted to temperatures below approximately 80° C. Furthermore, OSL signals from the Eldzhurtinsky Granite may reflect cooling of the rock samples due to erosion to the Earth's surface. We show that the thermal stabilities of ESR and OSL signals in quartz have the potential to be used for the reconstruction of the thermal histories of geological units that have cooled to ambient Earth's surface temperatures during the Quaternary.