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.
Ancient baking left deposits of ash and charcoal, which are very useful for dating.
The 1995 set of radiocarbon dates tended to be 100 to 200 years older than the dates, which was about 200 years younger than our 1984 dates.
In spite of this discrepancy, the radiocarbon dates confirmed that the Great Pyramid belonged to the historical era studied by Egyptologists. Koch Foundation supported us for another round of radiocarbon dating.
We broadened our sampling to include material from: We also took samples from our Giza Plateau Mapping Project Lost City excavations (4th Dynasty), where we discovered two largely intact bakeries in 1991.
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.Scientists have developed calibration techniques to adjust for these fluctuations.While alive, all plants and animals take C14 into their bodies.We then compared our results with the mid-point dates of the kings to whom the monuments belonged (Cambridge Ancient History, 3rd ed.).The average radiocarbon dates were 374 years earlier than expected.The radioactive carbon isotope is no longer replenished; it only decays.