On the analysis of lead objects in an attempt to determine their age

This paper reports on the materials analysis of a set of lead objects, commonly referred to as “the Jordan codices” in an attempt to shed some light on when they were manufactured. The codices are controversial, debate centring on whether they date to the early Christian period or are modern fakes. We report, for the first time, trace element analysis of samples from the lead codices as well as pieces of modern lead by PIXE and RBS to explore the trace element “fingerprint” of the metal used; the lead isotope composition by MC-ICP-MS can identify the geo location of the origin of the materials used; the alpha particle emission from the lead due to the presence of the 210 Pb isotope; and the amount of helium that is trapped in the lead due to the radioactive decay of trace amounts of 238 U and 232 Th contained in the material − the (U + Th)/He age. No single technique is able to show conclusively that the objects are either modern or ancient. All four techniques suffer weaknesses, which prevent a definitive conclusion from being reached. However, there are indications that while some of the objects examined show signs of being contemporary, others appear to be older. It can be concluded that for some key examples we have been unable to show them to be made from contemporary materials and would suggest that this provides a good reason for scholars to treat the objects seriously and to perform further research on these objects.