  We examine star formation and chemical enrichment in protoclusters (PCs)
using cosmological zoom-in hydrodynamic simulations. We find that the total
star formation rate (SFR) in all PC ($>10^{14.4}\,h^{-1}$M$_\odot$) reaches
$>10^4\,\mathrm{M}_\odot \mathrm{yr}^{-1}$ at $z=3$, equivalent to the observed
PCs. The SFR in the Core region accounts for about $30\%$ of the total star
formation in the PC at $z\gtrsim1$, suggesting the importance of the outer
regions to reveal the evolution of galaxy clusters. We find that the total SFR
of PC is dominated by galaxies with
$10^{10}\,\le\,(\mathrm{M}_\star/M_\odot)\,\le\,10^{11}$, while more massive
galaxies dominate the SFR in the Core. For the chemical abundance evolution, we
find that the higher-density region has a higher metallicity and faster
evolution. We show that the [O/Fe] vs. [Fe/H] relation turns down in the Core
at $z=3.4$ due to the enrichment of Fe by Type Ia supernovae. We find no
environmental effects for the mass--metallicity relations (MZR) or $\log$(N/O)
vs. $12+\log$(O/H) for galaxies. We find that the chemical enrichment in galaxy
clusters proceeds faster in the high redshift Universe ($z>1$). Our work will
benefit future tomographic observations, particularly using PCs as unique
probes of accelerated structure formation and evolution in high-density regions
of the universe.
