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[SCG56-12] Thermoluminescence and impurities of quartz from Sambagawa metamorphic belt, central Shikoku
Keywords:Gamma radiation-induced thermoluminescence, Sambagawa Metamorphic Belt
The purified quartz grains were irradiated with a 60Co gamma irradiator, using a dose of 5 kGy. TL emissions were measured at Okayama University of Science and Akita University. Trace element concentrations in the grains were measured by Agilent 7500 Series LA-ICP-MS. Paramagnetic defects were determined using JEOL PX-2300 SER spectrometer at Okayama University of Science.
A high intensity of the peaks below 200 °C favors the lower metamorphic grade. On the other hand, TL emissions at above 200 °C tend to increase with the higher metamorphic grade. There is an obvious decreasing tendency in Al content with increasing metamorphic grade, while no significant difference in concentration of Ti. It was measured that Al center is presented in all samples, whereas E´ center and Peroxy center are commonly existed in the higher metamorphic grade samples. It is reasonable to consider that the declenation of Al content, and the existance of E´ center and Peroxy center with increasing metamorphic grade presumably influences the characteristics of the TL temperature peaks in the samples.