Archaeomagnetic dating : investigating new materials and techniques
This thesis describes the application of archaeomagnetic techniques to the study of archaeological materials from Britain and China. It also explores the compilation and construction of the archaeomagnetic calibration curve, with particular reference to British data. One of the primary objectives of this study has been to extend the range of materials dated by archaeomagnetism to include waterlain sediments. Over 30 different sediments from a wide variety of archaeological environments were investigated by archaeomagnetic methods. Information on the environment of deposition was provided by measurements of magnetic fabric, while isothermal remanent magnetisation determinations were used to identify the magnetic minerals present. The results have been compared with the archaeological evidence and in many cases good correspondence has been found. It has been possible to make some general inferences as to which environments are most likely to yield sediments datable by archaeomagnetism. Similar measurement techniques were used to study six, dated, fired structures from the Xi'an area of Shaanxi Province, China. Together with other archaeomagnetic data published for this vicinity, these measurements provided the nucleus of information necessary for the construction of a calibration curve for this region and their magnetic properties were compared with those of the sediments. Central to both the study of sediments and Chinese fired material was the construction and use of the archaeomagnetic calibration curve. A database was formulated and implemented in order to archive British archaeomagnetic information and provide a basis on which to construct a revised curve. A number of methods of curve production were examined, particularly 'moving window' smoothing, which provided a rigorous, mathematical approach and produced a curve with realistic error bounds.