Crystallographic investigation of the huttenlocher exsolution at high temperature

Three plagioclases in the composition range An_66–70 from the different geological environments were selected for investigation of the Huttenlocher exsolution by Laue and Weissenberg methods with monochromatic X-ray radiation. In order to find the characteristics of the Huttenlocher exsolution at high temperatures heating experiments were carried out. The reversible phase transition between body centered plagioclase and high plagioclase in the anorthite-rich composition of the plagioclase and the irreversible transition from intermediate plagioclase to high plagioclase in the anorthite-poor composition were observed.