Morphology and Petrography of Shock-Produced Melt Veins and Melt Pockets

Abstract

Our micro-mineralogical study revealed that the Yanzhuang meteorite contains a great amount of shock-produced melt veins and melt pockets. The melt veins and melt pockets make up a network, penetrate through the unmelted chondritic rock, and indicate a non-equilibrium shock effect. It has been revealed that the melt veins and melt pockets are composed of fine-grained matrix consisted of recrystalline microcrystallites of idiomorphic olivine and pyroxene, silicate glass, and FeNi–FeS eutectics. The FeNi–FeS eutectics in the melt material usually have a directional arrangement, which characterize a flow texture of melt material. The chemical compositions of the unmelted chondritic rock are similar to that of the melt material. Small amount of iron from metallic iron and FeS had been fractionated into silicates in the melt material.