THE DISCOVERY OF AN ANGLO-SAXON GRUBENHAUS AT NEW BEWICK, NORTHERN UK USING ELECTRICAL SURVEYING AND PREDICTIVE DECONVOLUTION

摘要

Twin-probe and 33-fold multiplexed Wenner electrical resistivity surveys were carried out at New Bewick, northern UK to examine the extent of crop marks and potential Grubenhuser (sunken-featured buildings, sunken-floored buildings or SFBs). The twin-probe method was faster, but provided data with a lower spatial resolution. However, the Wenner array data was affected by characteristic ‘M’- or ‘W’-shaped responses over filled excavations such as those expected to represent a Grubenhaus. The raw Wenner array data have been analysed using one-dimensional and two-dimensional predictive deconvolution in order to remove these artefacts. The deconvolution was carried out using an inverse matrix element method. The filtered results indicate the presence of anomalies consistent with the presence of at least six Grubenhuser and other anomalies concurrent with the linear crop-marks. One particular anomaly measured about 5 m by 4 m and with a pit depth of 0.6 m below 0.3 m of topsoil. This anomaly was subsequently excavated and a Grubenhaus was discovered at the site. The excavated Grubenhaus measured 4.7 m by 3.9 m with a pit depth of 0.5 m below the base of the topsoil, confirming the electrical survey results.