Thermoluminescence Characteristics of Yanzhuang Meteorite

Abstract

The Yanzhuang meteorite is a heavily shocked chondrite and composed of light-colored unmelted phase and black-colored melted phase. Our thermoluminescence (TL) determinations have revealed that the intensities of natural TL for its unmelted phase and melted phase are different. The equivalent β-dose of unmelted phase is in about three times higher than that of melted phase, indicating the temperature of melted phase is much higher than that of unmelted phase. Two special TL phenomena have been found in Yanzhuang meteorite through the determination of the natural TL, annealed TL, and induced TL by β-radiation: (1) When the sample of Yanzhuang meteorite is annealed at temperature up to 500 °C, the TL peak induced by β-rays moves to lower temperature with the increasing of irradiation dose; (2) when the annealed temperature is greater than 600 °C, the TL peak temperature of the annealed sample is higher than that of the unannealed sample, indicating the shock effect changes the TL characteristics of the chondrite. The measured equivalent β-dose for the Yanzhuang unmelted and melted phases are 9238 Gy and 2753 Gy, respectively, showing that the thermal event age for the two parts in this meteorite is not equal, and their thermal histories are not the same, either.