 Biotite schist, fuchsite quartzite and paragneiss recorded an isotopic age of 3.88–3.55 billion years.This further reinforces the existence of a Hadean-Eoarchean crust, which later became the sedimentary protolith of the metamorphosed sedimentary rocks.In Xinyang, at the southwestern edge of the Eastern Block, 3.6 billion-year-old zircons from felsic granulite xenoliths were found.