Expert: Ralph Salier - 8/26/2009

Question
How are ancient Egyptian finds (specifically clay tablets and pottery) dated?

I understand Carbon Dating does not work on items that are not organic. Is that true?

What tests do work?



Thanks,

Andreas  

Answer
Hi Andreas,

Although it is true that C-14 does not work on inorganic materials, clay tablets, pottery and other similar items may have been fired which could cause carcoal to be embedded in the matrix of the clay.  In addition, materials like straw, shell, fibers and other materials were added to the clay before firing which can also lead to the dating of a pot or tablet.  Also, there are some clever dating systems that can date a clay lined hearth for instance.  This is due to changes in the magnetic flux of the Earth.  This causes the magnetic particles in clay to align with magnetic north and  then fixes them in orientation as the clay cools.  The difference from modern magnetic north can give a date close to +/- 20 years.

Also if materials like pumice or ash were used in the clay matrix that came from a volcanic eruption, these may be dated as well based on their chemical make up.  This chemical make up can identify the volcano and the eruption that the materials came from.  Many volcanoes and their eruptions have been dated and "chemically finger printed".

The other things that is commonly done in both Egyptian sites and other classical sites is to associate the find to a wooden object from the same tomb.  This then is C-14 dated and this should be a common date for all of the materials in the tomb.