High-Pressure Polymorphic Modifications of Minerals in the Products of Impact Metamorphism of Polyminerals Rocks

High-pressure phases of olivine and pyroxene composition were obtained in laboratory experiments with spherical converging shock waves at Zababakhin All-Russian Research Institute of Technical Physics. These experiments were conducted with three samples of different composition. The high-pressure phases developed after biotite and garnet, i.e. minerals that had compositions different from those of the high-pressure phases. The shock pressure under which these newly formed minerals crystallized were approximately three times higher than the static pressures needed to synthesize these minerals. In nature (in astroblemes these minerals can be preserved only in ejects from the craters, during the super fast quenching of the products of shock metamorphism.