Dynamic crystallization of shock melts in Allan Hills 77005: Implications for melt pocket formation in Martian meteorites

Comparison with previous crystallization experiments on melt pockets in Martian basalts indicate that the predominance of dendritic crystal shapes reflects the likelihood that those melt pockets with lower liquidus temperatures will be more completely melted, destroying most or all nuclei in the melt. In this case, crystal growth takes place at high degrees of supercooling, yielding dendritic shapes. It appears as though the melting process is just as important as cooling rate in determining the final texture of the melt pocket, as this process controls elimination or preservation of nuclei at the onset of cooling and crystallization.