Constraining the lithological diversity and geodynamic regime(s) of the earliest Earth is critical to understanding how our planet has evolved, and the discovery of Hadean- and Eoarchaean-age zircons has allowed us to directly analyse material from these eons. Here we use Jack Hills Zircon (JHZ) (3.3 - 4.2 Ga) analyses coupled with new experimental partitioning data to model the SiO2 wt.%, Si+O isotopic composition, and trace element (TE) contents of their parent melts; i.e., the composition of the Earth’s earliest crust. Comparing our derived JHZ parent melt Si+O isotopic compositions (-1.96≤ δ30SiNBS28 ≤0.39 ‰; 5.28 ≤δ18OVSMOW≤10.03 ‰) to younger continental crust lithologies, we conclude that the chemistry of the JHZ parent melts was influenced by the assimilation of serpentinites, cherts and silicified basalts, followed by igneous differentiation, leading to the formation of intermediate to felsic melts in the early Earth. Trace element measurements also show that the formational regime had an arc-like chemistry, consistent with the presence of mobile-lid tectonics in the Hadean. Moreover, based on the similarity of isotopic data derived for Eoarchaean and Hadean melts, we propose these continental-crust forming processes operated continuously, and uniformly, from the Hadean into the Archaean.