  Recent studies of heavy r-process elements in low [Fe/H] halo stars have
suggested that an initial population of metal-free very massive stars (VMSs)
may be required to provide early Fe enrichment without coproducing heavy r
nuclei. We find similar abundance trends in alpha-elements (which should be
copiously produced by VMSs), but not in other elements such as carbon (which
should not), in agreement with this hypothesis. We then combine the
corresponding level of prompt initial enrichment with models of VMS
nucleosynthetic yields and spectra to estimate the corresponding ionizing
fluxes. The result suggests that there may have been enough VMS activity to
reionize the universe. The unusually hard spectrum of VMSs would imply a
different reionization history from canonical models. HeII could have been
reionized at high redshift, only to recombine as a subsequent generation of
stars formed with a ``normal'' initial mass function.
