Oldest radiocarbon dating
The radioactive carbon isotope is no longer replenished; it only decays.
Samples older than 50,000 to 60,000 years are not useful for radiocarbon testing because by then, the amount of C14 remaining is too small to be dated.
For Khufu’s Great Pyramid, they scatter over a range of about 400 years.
We have fair agreement for the 1st Dynasty tombs at North Saqqara between our historical dates, previous radiocarbon dates, and our radiocarbon dates on reed material.
Test results from Middle Kingdom pyramid (Senwosret II).
Ancient Egypt’s population was restricted to the narrow confines of the Nile Valley with, we assume, a sparse cover of trees.