Thursday, 6 March 2014

Focus on UK Metal Detecting: What's this all about?

What are these guys doing? They're archaeologists and they are not digging? Eh? No metal detectors either?
Prospekcja powierzchniowa na węgierskich polach. Fot. S. Rzeźnik
This presumably is a sight few metal detectorists have ever seen, to judge by their evident lack of understanding about the value of surface evidence for archaeological survey. Thus we have Andy Baines over on his 'diary of a detectorist' blog writing rubbish like "David Knell and Paul Barford are missing the point" 6 March 2014). Actually its Baines who's not really grasped what we are talking about. So we see him protesting:
How can we be slated for digging up finds that are in the plough soil and have been moved around for hundreds If not thousands of years.  They are not in there (sic) context, they haven't been since farmers used the land.  There is nothing that can be learnt except from the item itself.[...]  there was no [context] to record as the find has been dragged out of it by the plough for years. How come them (sic) guys cannot see that ?
well, perhaps it is not Mr Baines' fault, if you look on the PAS website for even some text or pictures to help explain it to him, there ain't none. Nowt. Why that is is a very good question...  Now, funnily enough this is what tekkies have been saying for donkey's years, and their capacity for learning is such that you can tell them and tell them until you are blue in the face and they'll keep repeating the same old junk year in, year out. Perhaps that's why the PAS don't bother.

Anyhow, in the days when the PAS had a public forum, in deep PAS-prehistory, this problem came up. I was writing something on it at the time (in Polish for my students) and had a bibliography prepared. I posted it up on the Forum to demonstrate, if nothing else, that there was a huge literature - much of it produced by British archaeologists on precisely this aspect of to what degree (and when) ploughing disrupts existing patterns of surface artefacts. To cut a long story short the frequency with which surface archaeological survey (fieldwalking) has been used as a primary technique in landscape archaeology on almost all continents for the past several decades is proof enough that most archaeologists think the effects of ploughing are less significant than original patterns of deposition than Mr Baines. Of course my bibliography disappeared when the PAS closed their forum, if they'd asked, I'd have allowed them to put it on their website so their "partners' could see it. Well, I'll not make that mistake again.

So, instead of lots more words, here's two pictures for Mr Baines and his like-minded mates. Here's a load of dugup old stuff. How much of that would he be joining to his collection? There's a nice brooch, some rings, some lumps of crud, a few pieces of decorated pot. What about the knife? The iron strip fragment? Would he take those nice lumps of slag?  All those little potsherds? Well, I think one can compare this array of typical artefacts with what gets recorded. Let's be fair here, let us look at the finds recorded not by somebody else (the PAS), but BY detectorists FOR detectorists on the UKDF Datebase. How representative of real assemblages is what the artefact hunters have picked out there for collection and recording? Have a good look and see for yourselves.

As can be seen, collectors are very selective in what they take home and put in their mahogany cabinets. Now, the importance of all the finds in my composite picture above is that they are all real archaeological finds from real archaeological sites right in the middle of Europe. Some of them have come right off the Ministry of Culture website. This is what archaeologists study. Those pieces of brown crud on the left, well, they are in fact very interesting when you know what the are and what their context is, but most UK detectorists discriminate out iron.

Now I am sure that Andy Baines is going to reply that he collects (or would) everything, even stuff like this and he has a shed full of it. That may be, I think he'd be the exception, which you can very easily check by looking on any detecting forum near you and glancing at the photos of Today's /yesterday's/ weekend's finds. They don't look like this, but show a very specific selection of object types. But the shedfull of crud brings us to the second picture:

It represents a ploughed site in two separate fields next to an area of pasture (where no surface finds can be found and plotted). There are three discrete scatters of finds in the ploughsoil relating to three separate archaeological events or processes on that spot in the past. They might be separate phases (first century AD Roman, 3rd century Roman), they may relate to zonation of activities (one scatter might be slag and fired clay, another roofing tile from collapsed wooden buildings). An archaeological field survey would grid-walk such a site and analyse the scatters - for example it looks like the orange spots could be  restricted to a rectilinear area, and perhaps the scatter going down towards the bottom right corner is the upper fill of an enclosure ditch (check the cropmarks, geophys). The distribution suggests that the site continues into an adjacent field - which has heritage management implications. The establishment of the current field boundary seems likely to be later than all three spreads, possibly ploughed-out features are represented by the scatter, and so on.

What's going to happen when a metal detectorist gets on that field and starts looking for collectables and hoiking them out? Well, first of all his tool does not detect fired clay, tile and pottery, or bones or anything else like that which is also a component of those scatters. His main interest in the slag is going to be that its going to throw his signals out and he'll be cursing it by the end of the day if he cannot set the detector to discriminate it out, yet some of that slag is very characteristic of a specific smelting process. Not collecting those pieces loses a piece of information about what was happening on that site.   If he fails to stoop to pick up the brown iron crud and take it home and stick it under his domestic radiographic unit, he's not going to find out he'd found a rare site with Roman chain mail on it. In fact they come from a ploughed-out cremation, another piece of information about what the site was used for (which he'll most likely not spot as the cremated bone is in small pieces and does not produce a bleep).

Now imagine that the spreads are more discrete,  and in them are diagnostic metalwork finds, some buckles, strapends, tools - something which can suggest a date for the associated material, or perhaps say something about what was going on at this site (military equipment for example). That is precisely the stuff the metal detector is is going to make off with at once.  Anything like that is precisely what a collector is looking for. Taking it away however, totally obliterates any chance that any subsequent examiner of the site can find that information. It may be argued that the find might be one of the one in five finds that is recorded by the PAS. It might be, but if it has a six-figure or even eight figure NGR, then its next to impossible to associate it years later on the basis of the PAS records with a specific context for example in the example given above.

The main point is that, depending on what kind of archaeological evidence these spots represent, in most cases it is not going to be possible to analyse these scatters 'live' in the field and plot them straight onto a map. It might be possible if they represent obvious categories, samian versus amphora sherds, Early Iron Age versus willow-pattern, but even so, the individual finds should be bagged up individually (or at least by grid) with the co-ordinate clearly associated with each piece or group of pieces of evidence.   

Individually bagged finds
How many metal detectorists' personal artefact collections contain the full range of crud (picture 1)  from even one site collected according to its detailed distribution across the site (picture 2) and stored in a manner allowing the analysis - and re-analysis of the patterns? When we've answered that question , we can perhaps approach the answer to Mr Baines' plaintive question about what the difference in approach is between how an archaeologist sees the sites these people deplete in their search for collectables, and how they see them. 

UPDATE 7th March 2014:
See also here:  'Focus on UK Metal Detecting: Not Doing the Service to History People Say'.

1 comment:

Steven Broom said...

Hi Paul... a fascinating post... I am trying to identify and collect the "other stuff" whilst I am out and managed to retrieve around 4 fragments of what I think is roman greyware from site at the weekend. Posts like this are an excellent marker for the additional effort that we can make.

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