Comparison of Shock Features in Yanzhuang with Those of Experimentally Shocked Jilin Meteorite

Abstract

Samples of the Jilin H5 chondrite were experimentally shock-loaded at the peak pressures of 12, 27, 39, 53, 78, 83, 93, and 133 GPa. The aim of this study is to compare experimentally shock-induced phenomena with those in naturally shocked Yanzhuang H6 chondrite. Planar fractures, mosaicism, brecciation in olivine and pyroxene, as well as transformation of plagioclase into diaplectic glass were observed in the Jilin samples shocked at pressures lower than 53 GPa. Shock-induced chondritic melts were first obtained at P > 78 GPa and more than 60% of the whole-rock melting was achieved at P ~ 133 GPa, and that shock-induced silicate melt consists of quenched microcrystalline olivine and pyroxene, metal, troilite, and vesicular glass. No high-pressure phases were observed in any of the experimentally shocked samples, neither in the deformed nor in the molten regions. Deformation features in Jilin samples shock-loaded below 53 GPa are comparable to those found in Yanzhuang chondrite. The mineral assemblages in the molten regions in the shocked Jilin samples are also comparable to those encountered in the heavily shocked Yanzhuang chondrite. Based on the experimental study on Jilin samples, the peak pressure and shock temperature for the Yanzhuang unmelted chondritic rock are estimated to be 45–60 GPa and 600–900 °C, and those for the Yanzhuang melted bodies are >60 GPa, and 2000 °C.