R5: Extraterrestrial materials

[R5-14] The complex shock metamorphism history recorded in the Padvarninkai

*Masaaki Miyahara¹, Akira Yamaguchi², Eiji Ohtani³ (1. Hiroshima Uni. Sci., 2. NIPR, 3. Tohoku Uni. Sci.)

Keywords:eucrite, silica, plagioclase, high-pressure polymorph

We investigated the shock-induced melting textures and high-pressure polymorphs therein in the eucrites Padvarninkai with FE-SEM and Raman spectroscopy. The shock-melt veins included coesite, Ca-pyroxene and garnet-like minerals as high-pressure polymorphs. Both the progressive and retrograde phase transitions occurred in the shock-melt veins, suggesting that the shock metamorphism recorded in Padvarninkai is not simple.