Experimental investigations of silica under high pressure and temperature offer crucial insights into modeling of Earth and super-Earths’ interiors. Despite extensive studies on Hugoniots of silica polymorphs like fused-silica (2.20 g/cm³), quartz (2.65 g/cm³) and stishovite (4.29 g/cm³) up to a terapascal, unexplored region of melting and liquid of silica at high pressures is leaved because of the Hugoniots dependence on ambient density. This emphasizes the urgence to supplement the phase diagram to constrain silica properties under extreme conditions. Here, the Hugoniot and shock temperature of coesite (2.92 g/cm³) were studied by laser shock compression experiments up to 950 GPa. Our findings confirm shock-induced superheating in coesite, revealing a higher Grüneisen parameter and lower electrical conductivity compared to those of fused-silica and quartz along an isothermal line (<2 × 10⁴ K). These results suggest unique properties of shocked coesite, which imply a warmer and longer-lived silica magma ocean of earlier rocky-planets.

中文翻译：

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铜锣矿的冲击压缩高达 950 GPa


在高压和高温下对二氧化硅的实验研究为地球和超级地球内部的建模提供了重要的见解。尽管对熔融石英 （2.20 g/cm ³ ）、石英 （2.65 g/cm ³ ） 和辉石 （4.29 g/cm ³ ） 等二氧化硅多晶型物的 Hugoniots 进行了广泛的研究，但高达 terapascal，由于 Hugoniots 对环境密度的依赖性，在高压下留下了未开发的二氧化硅熔化和液态区域。这强调了补充相图以限制极端条件下二氧化硅特性的紧迫性。在这里，通过高达 950 GPa 的激光冲击压缩实验研究了钙石的 Hugoniot 和冲击温度 （2.92 g/cm ³ ）。我们的研究结果证实了共晶石中由冲击引起的过热，与沿等温线 （<2 ⁴ × 10 K） 的熔融石英和石英相比，显示出更高的 Grüneisen 参数和更低的电导率。这些结果表明了激波钙岩的独特特性，这意味着早期岩石行星的二氧化硅岩浆海洋更温暖、寿命更长。