We have investigated chemical evolution in the young universe by analysing the detailed chemical enrichment pattern of a metal-rich galaxy at high redshift .
The recent detection of over 20 elements in the gas-phase of a damped Lyman- \alpha absorber ( DLA ) at z = 2.626 
represents an exciting new avenue for exploring early nucleosynthesis .
Given a strict upper age of \sim 2.5 Gyr and a gas-phase metallicity about one third solar , we have shown the DLA abundance pattern to be consistent with the predictions of a chemical evolution model in which the interstellar enrichment is dominated by massive stars with a small contribution from Type Ia supernovae .
Discrepancies between the empirical data and the models are used to highlight outstanding issues in nucleosynthesis theory , including a tendency for Type II supernovae models to overestimate the magnitude of the “ odd-even ” effect at subsolar metallicities .
Our results suggest a possible need for supplemental sources of magnesium and zinc , beyond that provided by massive stars .