The initial spark of the first beep, leading to the building excitement as the signal gets stronger and the target gets closer, then the first glimpse ….is it? Isn’t it? …What is it?? Curiosity emerges, and a deeper interest starts to form – what was it doing there? How did it get there? Where did it come from and who might have put it there? How does it relate to any other pieces that came up nearby?
A metal detector survey is also a form of prospection, and one that is very closely concerned with artefact studies. Used appropriately, a metal detector can be a valuable tool for archaeologists. The identification of sites where the type and duration of human occupation did not leave signatures that can be easily detected by other forms of geophysics, or indeed by excavation itself.
Battlefields are a prime example of a site that is best understood through metal detector survey. Early modern conflicts often saw engagement taking place over wide tracts of land with little alteration to the landscape as a result. Contemporary descriptions can assist with tying down the locus of the action, but can be misleading and can be difficult to relate to the modern landscape. Metal detectors are a valuable tools in identifying a battle's location, and sometimes can aid an understanding of the progress of the battle, by plotting the debris left over once the combatants have departed the field. This debris can include items relating to the weapons used, perhaps iron arrowhead or lead shot depending on the period, and metallic fitting from participants clothing, from horse harness or from other pieces of equipment.
Metal detectors also have a role in developing an understanding sites that have been subjected to excavation. Three seasons of metal detecting at Catterick, before the site was protected by scheduling, added to an understanding of the archaeology of the area. This was in addition to providing some useful insights into the potential and limitations of a metal detecting survey. NAA were involved in this work, which was published in the Yorkshire Archaeological Journal.
Metal detectors can be set to detect all of the metals that were commonly used to manufacture past objects. Like other methods of prospection, the skill and experience of the person undertaking the survey is key to maximise the results that can be obtained from the equipment. Also of importance is the detectorists ability to follow a set transect and sweep pattern in the field, and finally the accuracy to which any located objects are recorded. All of these components need to be of equally high quality to gain the most comprehensive results and therefore achieve the highest potential for understanding, if one component is lacking it can lead to misinterpretation and the whole project suffers.
As archaeologists, the value of the objects discovered is in their cumulative potential, for instance through their distribution pattern. This means that groups and spreads of mundane iron items like nails can be equally important in understanding past activity as coins and other items of precious metal. That’s not to say we don’t appreciate a nice object as much as the next person, and such finds add important details to the story of a site, but it’s often the associated information with a find that makes an object more or less important to the bigger picture.