r-Process Abundance Variations in Globular Clusters as Fossils of Turbulent Mixing

Several metal-poor Galactic globular clusters exhibit substantial star-to-star r-process abundance variations at nearly fixed [Fe/H], with the ensemble suggesting smaller variations toward increasing metallicity. We investigate whether this chemical structure can be inherited from incomplete mixing in the galactic environments in which the clusters formed. Using parsec-scale simulations of rare-element transport in a supernova-driven turbulent disk, we follow the redistribution of r-process ejecta and characterize the abundance structure of gas selected to trace star-forming environments. Rare enrichment events generate strong [Eu/Fe] inhomogeneities that persist across a range of physical scales. As chemical evolution proceeds, the available abundance variance decreases, while spatial averaging over larger regions reduces the differences between their characteristic abundances. The simulations provide substantial pre-collapse r-process variance at low [Fe/H] and show the same broad decline toward higher metallicity suggested by the globular-cluster measurements. Our results support an interpretation in which at least some of the observed r-process variations are inherited from pre-existing chemical structure in the natal environment, allowing globular clusters to preserve a fossil record of the mixing history between rare enrichment and star formation.