116 / 2023-04-14 10:12:53

Experimental simulation and microstructural analysis of natural impact shocked reidite

high temperature and high pressure,zircon,reidite,impact

高压物理与材料科学 > 高压地球科学-海报

Natural hypervelocity impact processes provide extreme pressure-temperature conditions, which exert unique shock metamorphism on rocks and minerals.¹ Zircon (ZrSiO₄) responds to shock metamorphism in various ways, including crystal-plasticity, twinning, high-pressure phase transition to reidite, formation of lamellae or granular textures, dissociation to ZrO₂ +SiO₂ and so on, which serve as potential thermobarometers to record the extreme pressure-temperature histories in natural shock-metamorphic rocks.² Due to the complexity of natural impact processes, experimental simulations are very challenging: the dynamic high-pressure experiments can mimic the fast pressure loading and unloading shock front, while the static high-pressure experiments can well control temperature changes at different released pressures. We propose to combine “dynamic and static” experiments to simulate the metamorphism process of natural shocked zircons, and carry out further electron microscopy analysis on the recovered samples. In this study, we perform high pressure-temperature experiments in a laser-heated diamond anvil cell using prefabricated reidite by dynamic experiments and natural zircon samples, in order to shed light on the formation mechanism of lamellae and granular reidite observed in natural impact craters.