Can carbon dating be used on stone

We wanted to use science to test the accepted historical dates of several Old Kingdom monuments.

It is likely that, by the pyramid age, the Egyptians had been intensively exploiting wood for fuel for a long time.Because of the scarcity and expense of wood, the Egyptians would reuse pieces of wood as much as possible.The earliest experiments in radiocarbon dating were done on ancient material from Egypt. Libby’s team obtained acacia wood from the 3rd Dynasty Step Pyramid of Djoser to test a hypothesis they had developed.Libby reasoned that since the half-life of C years, the Djoser sample’s C14 concentration should be about 50% of the concentration found in living wood (for further details, see Arnold and Libby, 1949). Subsequent work with radiocarbon testing raised questions about the fluctuation of atmospheric C14 over time.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).

Some of this recycled wood was burned, for example, in mortar preparation.

If a piece of wood was already centuries old when it was burned, radiocarbon dates of the resulting charcoal would be centuries older than the mortar for which it was burned.

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.

The number of dates from the two projects was only large enough to allow for statistical comparisons for the pyramids of Djoser, Khufu, Khafre, and Menkaure. First, there are significant discrepancies between the 19 dates for Khufu and Khafre, but not for Djoser and Menkaure.