The dating of ancient metals: review and a possible application of the 226Ra/230Th method (a tutorial)

Abstract

Based on the known U-disequilibrium decay law whereof several dating methods have been devised (e.g. in dating speleothems, paintings, shells) a novel idea of dating ancient metals is presented based on the Radium-226 separation from metal during the smelting process. ²²⁶Ra is gone with slag and its products, while in metal it grows from remaining traces of ²³⁸U. Within about 8,000 years the growth reaches equilibrium which sets the upper limit to the method. A review of indirect dating methods of metallurgical remains is outlined, while the advantages and limitations of the novel method is discussed in connection to these metallurgical activities based on preliminary isotopic data.