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.
By measuring how much C14 remains in a sample of organic material, we can estimate its age within a range of dates.
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.
We focused our collection efforts on tiny pieces of these materials, along with reed and straw left by the ancient builders.
In 1984 we conducted radiocarbon dating on material from Egyptian Old Kingdom monuments (financed by friends and supporters of the Edgar Cayce Foundation).
We thought that it was unlikely that the pyramid builders consistently used centuries-old wood as fuel in preparing mortar.
The 1984 results left us with too little data to conclude that the historical chronology of the Old Kingdom was wrong by nearly 400 years, but we considered this at least a possibility.
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.
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 numbers of C14 atoms and non-radioactive carbon atoms remain approximately the same over time during the organism’s life.