Structural Response of Laser-Driven Shock Compressed Albite

초록

Plagioclase records characteristic shock features that constrain meteorite impact conditions, but its phase evolution along the Hugoniot remains unresolved. We investigated shock-induced phase transition in albite using in situ X-ray diffraction during laser-driven shock at 14-66 GPa. Albite retained its crystal structure up to at least 14 GPa and underwent complete amorphization above 28 GPa, at pressures lower than those reported in shock-recovery experiments. No hollandite-type phase, jadeite, or Ca-ferrite-type NaAlSiO4 was observed during shock loading, indicating that the high-pressure region of the albite Hugoniot is dominated by amorphization. Upon decompression, crystalline peaks reappeared, indicating structural recovery, which may contribute to the wide range of amorphization pressures in the recovery experiments. The absence of decomposition products indicates strong kinetic suppression under nanosecond shock durations, defining the short-timescale limit of albite decomposition during impact loading. These results refine interpretations of shock metamorphism in plagioclase under planetary impact conditions.

키워드