Electrochemical age determination of archaeological bronzes

Archaeological bronzes are still dated exclusively typologically and relatively by their find context. Lead isotope analysis (210Pb) on bronzes can provide moreover information on whether the object was made with metal that is less than 150 years old; however, this is not relevant for archaeological bronze objects deriving from a secure find context. First results from electrochemical examinations indicate that bronzes can also be relatively dated on the basis of selected corrosion products. The analysis is considered non-destructive, as only a few mg of corrosion are dabbed from the surface of the bronze. Using voltammetry of immobilised particles (VIMP), the ratio of the copper oxides cuprite and tenorite is measured, which provides information about the age of the object, respectively the time of its deposition in the ground. Analyses will be carried out in cooperation with the University of Valencia with leading scientists in the research field of electrochemical dating. Besides the electrochemical analyses, we will also investigate the influence of various factors such as chemical composition and microstructure on the measurements. By examining 250 bronzes from the Copper Age to the Middle Ages (ca. 2800 B.C. to 1000 A.D.), we will furthermore 1) assess the potential of VIMP for dating archaeological bronzes; 2) create a statistically calibrated reference data as a baseline for VIMP; and 3) evaluate the potential of VIMP for the identification of recent forgeries. In addition, chemical and spectroscopic analyses of the samples provide a detailed characterisation of the individual corrosion products. The project bridges the gap between natural science and humanities by providing analytical data for the age of archaeological bronzes through analysis of the objects themselves rather than their find contexts this means it can be applied also to objects with unknown find context. It is the aim of CHRONOCU to establish voltammetry as a standardized methodology to determine the age of archaeological bronzes, and provide calibration data for future studies.

Archaeological bronzes are still dated exclusively typologically and relatively by their find context. Lead isotope analysis (210Pb) on bronzes can provide moreover information on whether the object was made with metal that is less than 150 years old; however, this is not relevant for archaeological bronze objects deriving from a secure find context. First results from electrochemical examinations indicate that bronzes can also be relatively dated on the basis of selected corrosion products. The analysis is considered non-destructive, as only a few mg of corrosion are dabbed from the surface of the bronze. Using voltammetry of immobilised particles (VIMP), the ratio of the copper oxides cuprite and tenorite is measured, which provides information about the age of the object, respectively the time of its deposition in the ground. Analyses were carried out in cooperation with the University of Valencia with leading scientists in the research field of electrochemical dating. Besides the electrochemical analyses, we will also investigate the influence of various factors such as chemical composition and microstructure on the measurements. By examining over 300 bronzes from the Copper Age to the Middle Ages (ca. 2800 BCE to 1000 CE), we will furthermore 1) assess the potential of VIMP for dating archaeological bronzes; 2) create a statistically calibrated reference data as a baseline for VIMP; and 3) evaluate the potential of VIMP for the identification of recent forgeries. In addition, chemical and spectroscopic analyses of the samples provide a detailed characterisation of the individual corrosion products. The project bridges the gap between natural science and humanities by providing analytical data for the age of archaeological bronzes through analysis of the objects themselves rather than their find contexts - this means it can be applied also to objects with unknown find context. It is the aim of CHRONOCU to establish voltammetry as a standardized methodology to determine the age of archaeological bronzes, and provide calibration data for future studies.