Zircon Thermometry of the Yarot Granite Massif (The Subpolar Urals)

Abstract

Zircon is one of common accessory minerals of igneous rocks. Geochemical and morphological features of this mineral reflect physicochemical properties of the mineral formation medium. It provides additional information about the nature and formation conditions of the rock. A considerable experience of using zircon as a geothermometer has been accumulated at present. It helps determine a more accurate rock-forming temperature regime. The results of the study of accessory zircon from the Yarot granite massif (the Subpolar Urals) are presented in this paper. The data obtained by different methods (the Watson saturation thermometry and the classical evolutionary morphological analysis according to J. Pupin and G. Tyurko) were compared. The formation of the Yarot massif granites took place at an average temperature of 841 ℃ (range: 806–926 ℃) according to the Watson saturation thermometry. The study of the Yarot massif zircons gave a range from 750 to 900 ℃ using an evolutionary-morphological analysis. The average crystallization temperature of rocks was 843.75 ℃ according to Pupin. The Subpolar Urals granite formation temperatures were specified. The obtained temperatures were higher than the thermometric data of M. V. Fishman and his colleagues for this massif. Previously scientists assumed that the Yarot granite massif was formed at temperatures not higher than 720 ℃.