Effects of shock pressures on calcic plagioclase

摘要: Samples of single crystal calcic plagioclase (labradorite, An63, from Chihuahua, Mexico) have been shock-loaded to pressures up 496 kbar. Optical and electron microscopic studies the recovered samples show effects increasing shock on this mineral. At 287 kbar, specimens are still essentially crystalline, with only a trace amount optically unresolvable glass present at after shock-loading between 300 400 kbar almost 100% diaplectic glasses; that is formed by transformation presumably in solid-state. Above about glasses refractive indices similar thermally fused were produced. The general behavior index refraction agrees closely previous work, however, absence planar features striking. less than most prominent physical feature pervasive irregular fracturing caused crushing, although some (001) (010) cleavages observed. No fine-scale deformation structures, i.e. features, noted any specimens. We conclude, contrast shocked rocks not necessarily definitive indicators, (e.g., maskelynite) high-pressure phases, but rather likely indicative local heterogeneous dynamic stress experienced grains within rocks.