Integrated signal enhancements in magnetic investigation in archaeology

The magnetic method can be efficiently applied to archaeological investigation especially when the S/N ratio is enhanced appropriately. This study presents a model experiment and field examples of magnetic exploration in archaeology. By using appropriate measuring processes and filtering methods, the conventional and more recent magnetic prospecting techniques are successfully applied to the very shallow, small-scale investigations, which are used to locate and map archaeological targets. We focus on mapping the buried slate caskets in the alluvial environment, which is the most commonly encountered and readily preserved ones at the archaeological sites of Taiwan. The gradiometry and the inferred derivatives may resolve individual anomalies. Locations of the maxima determined by the 3-D analytic signals can be used to describe the outlines of the bodies that cause the anomalies. Furthermore, the susceptibility was very successful in mapping near-surface targets at the Chubin site. The magnetic results of the example at the Hutzushan site, compared to the GPR survey carried out by previous investigators, indicate that the GPR anomalies may be caused by other sources. The magnetic response of a casket can be displayed in various ways, depending on the pole distribution of the casket, the geometry, the magnetization direction and the orientation of buried casket. The processing methods may improve the data resolution, but precautions must be taken for the artifacts.