Mesosiderites are a class of stony-iron meteorites composed of approximately equal proportions of iron-nickel metal and silicate rock, and they do not occur as uniformly formed rocks but instead consist of numerous irregularly shaped fragments of different origins. These components were broken apart by large-scale impact events on their parent body, mixed together, and subsequently reassembled into a consolidated rock through compaction and solidification. In contrast to pallasites, which represent relatively ordered materials from a transition zone between a metallic core and a silicate mantle, mesosiderites form through large-scale impact processes in which both metal from deeper regions and silicate material from the outer crust were excavated and mechanically mixed. This produces a highly irregular texture in which metal and silicate clasts occur side by side, often showing clear evidence of shock metamorphism and localized melting. After their formation, these mixed rocks were further disrupted by later collisions, breaking larger rock masses into smaller meteoroids that gradually separated from their parent body, entered interplanetary space, and eventually reached Earth as mesosiderites.
