Chartered Institute for Archaeologists 2023

26 post-excavation, the resultant archive of portable heritage. However, is there a wider value beyond the information gained from artefacts? Could adopting DAPAS bring a commercially viable and consistent approach to learning from and saving our portable heritage? DPAS BASIC PRINCIPLES – COMBINING FIELDWALKING WITH METAL DETECTING WHEN REQUIRED ▪ Detailed: offers a consistent approach to retrieving dating evidence, set to a site- determined discard policy, offering an accurate and detailed sweep of 200m 2 grids through two-metre transects, located over important archaeological remains identified by a geophysics team or through desk-based assessment. With an initial GPS location point, the search area location grid can be efficiently moved or expanded, utilising set rope lengths to give a measured distance. ▪ Partial: covers larger search areas following a predetermined density of transects. The partial approach considers the required coverage of hectares to numbers of detectorist practitioners, against sweep rates. For example, a partial approach was recently utilised on an HS2 section where metal detecting, geochemistry and magnetic susceptibility were combined, based on 20m transects, while other sites may require a greater density of, say, five-metre transects. ▪ Detailed and partial surveys: look to maximise the effectiveness of searching for what can often be very small finds (a medieval coin can weigh as little as one gram). By setting out to a predetermined plan, achieving a consistent coverage of the search area, findspots will then be GPS-located and spatially plotted as dating evidence to be presented in the final report. Where possible, fieldwalking will be carried out at the same time as metal detecting. ▪ Trenching and excavation: utilising the metal detector to locate topsoil and subsoil in-situ metal artefacts, marked-out trenches are swept before digging and before each drawback of a mechanical excavator. Targets spots can be flagged for excavation. ▪ Spoil: volume to surface area makes locating finds in spoil heaps particularly inefficient. A maximise the potential for finding artefacts of all materials by restricting the depth of spoil and laying it out in lines away from the trench, relevant to layers excavated. ▪ Finds retrieval: detectorist practitioners are best placed to perform artefact extraction from topsoil when an object is located, rather than flagging it for extraction by others, as pinpointing the target is integral to the accurate retrieval of the artefact. Deeper signals will be flagged and reported to be Using a metal detector to pinpoint targets for investigation on an archaeological site ©Keith Westcott