By Alan S and Sandy Gerrard
“All archaeology is destructive” is a cry often heard from the lesser-spotted metal detectorist trying to defend their hobby. Even Mortimer Wheeler admitted that ‘excavation is merely methodical destruction’.
But how true is this?
Whilst it’s true that some field archaeology can be destructive, it’s surely more accurate to say that all archaeology is instructive. In terms of excavation techniques, it’s certainly true to say that carefully scraping away soil to reveal the hidden mysteries contained below is more rewarding than blindly shovelling earth to grab at hoped for treasures!
So to qualify that, in this short series let’s take a brief look at some of the different types of archaeology practised today and outline what each type involves.
Desk Based Archaeology
The phrase ‘Standing on the shoulders of giants’, used by Sir Isaac Newton (but with a much earlier origin), is used to describe the practise of research by referring to, and building upon the work of others. A large part of desk-based archaeology is based upon this principle, and should involve meticulous reference to previous research, excavation reports etc. Much of this can be done using a myriad of resources including: the Archaeological Data Service, Heritage Environment Records, libraries, old maps, National and County Record Offices, museums, satellite and aerial imagery, LIDAR or 3D imaging, and extrapolating information therefrom to identify potential new areas of investigation, or to strengthen or extend existing theories. No new excavation or collection of field data is involved, but future excavation plans may result from any findings.
Desk based analysis is often carried out to identify the potential for archaeological remains on the site of a planned development and may be used to inform planning decisions and highlight the need for mitigation. Where planning is granted and the archaeology will be destroyed or severely damaged the planning authorities should insist that a programme of archaeological work be carried out by the developer as a condition of permission being granted. In the most extreme instances where a whole site is earmarked for destruction the resultant excavation records will inevitably be the only tangible remains and this scenario is often euphemistically described as ‘preservation by record’. Desk-based archaeology is often the first stage of many archaeology projects, and of itself is not destructive – although as pointed out to me recently, reputations may rise or fall as a result of new interpretations of old data.
The next form of archaeological investigation involves getting out and looking at the site or landscape. This is important and offers an opportunity to establish the accuracy or otherwise of the desk based work and enable a fuller understanding of the resource. Many different techniques are available and the most suitable will depend on the character of the surviving archaeology. Where obvious earthworks survive survey work makes an excellent starting point. The production of a plan showing what is there and how all the different elements fit together allows the archaeologist to better understand what they are looking at.
Where they are few or no earthworks other techniques are needed to explore the past and amongst the better known are Geophysical surveys – the ‘Geofizz’ so beloved of Time Team aficionados. Sometimes a combination of earthwork survey and Geofizz can produce extraordinary results without causing any damage to the archaeology.
A third form of fieldwork which does inevitably erode the archaeological resource and can only be carried out within recently ploughed or cultivated fields is field walking which involves a planned traverse of the site on foot, looking for any artefacts (small finds) that may have been ploughed up to the surface. The Portable Antiquities Scheme was set up to record and interpret small finds, such as those uncovered by metal detectorists, activities such as informal field walking, and other chance finds. But in most cases field walking will be part of a larger project, and any finds will normally be documented as part of that project. Whilst field-walking itself is not necessarily destructive, it can lead to loss of information and ‘context’, if not properly planned and recorded.
There are many types of Geophysical survey, and indeed, metal detectors are but one tool in the geophysicist’s armoury. Most Geofizz tools work in a similar way, by sending electromagnetic signals into the ground and measuring the responses to build up a picture of any features which may be hidden below. Electro-magnetic resistivity and ground penetrating radar are the most common forms, with sonar being used for underwater archaeology sites. Whilst not destructive in and of itself, Geofizz aids in the project planning process, and is often a precursor to targeted excavation – the topic of the next part of this short series.