I think most of us are off digging ;-))

[Steve-B]

quote:I think most of us are off digging ;))

Tell you what, I for one would to read about the current projects that the BAJR archaeologists are currently working on, digging and non digging....

If you have a moment, please do tell....

www.detector-distribution.co.uk

If a job is worth doing, then its worth doing it tomorrow!

Homer (Simpson)

[Steve-B]

Soooo, your all betwn jobs at the moment...... ;):D

www.detector-distribution.co.uk

If a job is worth doing, then its worth doing it tomorrow!

Homer (Simpson)

[garybrun]

Looks like they dont want to get involved in a metal detecting discussion forum ;)

http://www.ukdfd.co.uk
Recording OUR heritage for future generations.

[John Walford]

Seeing as none of the more regular posters are rising to the bait, I'll chip in with my hap'orth.

At present I'm geophysing various parts of Northants and surrounding counties, mostly in advance of the usual road schemes and pipelines. Last week was slightly different as I spent a couple of futile days in the middle of Towcester surveying around the Bury Mount. We had been sent to find a moat (as shown on umpteen maps and still just about visble on the ground...) but mainly succeeded in detecting modern rubble and scrap iron which could have been mapped by a quick walk over survey had anyone really been that interested. (Developers, consultants and others please note; geophys doesn't work on scrappy overgrown urban sites where everybody and their dog has been dumping stuff since time immemorial)

John

"Hidden wisdom and buried treasure, what use is there in either?" (Ecclesiasticus ch20 v30)

[Steve-B]

Many thanks for your reply John, I really am genuinely interested in the day to day workload and projects that are currently being worked on.

Excuse my ignorance, but as you are geophysing are you immediately aware of the findings or is the data processed at a later date?

www.detector-distribution.co.uk

If a job is worth doing, then its worth doing it tomorrow!

Homer (Simpson)

[John Walford]

Steve

Normally the data is collected as a string of numbers, which pop up briefly on the instrument display as each reading is taken. Sometimes it's possible to get a general feel for what might be on a site by watching the numbers coming in but the sheer quantity of readings (900 per 30m grid square with resitance survey, 3600 with a magnetometer) means that only when everything is downloaded is it possible to make any reliable interpretations.

Usually the downloading is done in the field, at least once a day and often more frequently (depending in part on the internal memory capacity of the instruments we are using). We can then view a plot of the data to check its quality and see what, if anything, has shown up.

If you want to ask anything else, go ahead, but I may be a bit slow in responding as I will not have internet acess again until Friday evening.

John

"Hidden wisdom and buried treasure, what use is there in either?" (Ecclesiasticus ch20 v30)

[garybrun]

Thanks for the insight John.

http://www.ukdfd.co.uk
Recording OUR heritage for future generations.

[Steve-B]

Many thanks for the reply John.

Very interesting, I had presumed that you were just collecting the data without actually being involved in the interpretation of it.

My only experience in seeing geophysics at work has been whne watching the Time Team, I notice on there that they use several different types of equipment. Can I ask if the type of equipment you use is dependant upon the type of site being surveyed or can one 'do it all', do you have a favourite system that you prefer using, or does this not come into the equation.



www.detector-distribution.co.uk

If a job is worth doing, then its worth doing it tomorrow!

Homer (Simpson)

[m300572]

I'm working on a variety of things, related to site management 0 a landscaped park in Lancashire, selection of farm buildings repairs (mainly late 18th and early 19th Century)and trying to work out how much napalm I will need to specify to remove rhododendron infestation from a Scheduled moated site in Cheshire.

[Steve-B]

Peter, once you have decided if a site needs napalming or not, do you then get involved with the job, or is this then contracted out?

www.detector-distribution.co.uk

If a job is worth doing, then its worth doing it tomorrow!

Homer (Simpson)

[garybrun]

He only calls in the Napalm bombers when detectorists are on site :)

http://www.ukdfd.co.uk
Recording OUR heritage for future generations.

[m300572]

Its a Scheduled Monument so I would have to check to ensure they were not in possesion of a licence from the Secretary of State before I unleashed the Harriers!!!

If the job goes ahead I will write a spec for the ground clearance (in cooperation with the EH Inspector) and that will go out to tender. The spec is mainly to point out that there should be no ground disturbance (so they cant bulldoze it out, or rip out the stumps) that there should be no fires on the site (b*gg*r that's the napalm idea out - I may have to specify Agent Orange instead)and that the site should be surface seeded with an appropriate seed mixture (discussion with our ecologist for this one) so that the bare ground under the scrub is covered fairly fast.

[Steve-B]

Thats interesting, does you role include site inspections both before and after, or is it primarily an ofice based role?


www.detector-distribution.co.uk

If a job is worth doing, then its worth doing it tomorrow!

Homer (Simpson)

[garybrun]

hes a pen pusher Steve :)

http://www.ukdfd.co.uk
Recording OUR heritage for future generations.

[m300572]

I do go out and look at sites before the work is done - its difficult so do a spec otherwise. On average i get out of the office a couple of days a week - the rest of the time I batter a keyboard - pens are so yesterday's technology Gary!- drink tea and eat more than my fair share of the office biscuits whilst exchanging banter with online correspondants!!

Digging? In this weather!?? With my knees?? Are you mad?????!

[vulpes]

With respect to JW's Towcester experience I believe the auger survey succeeded where the geophysics failed. A question of the right technique for the job, perhaps?

[Steve-B]

This is real fascinating stuff guys, thanks for the replies, definately giving a deeper insight into practical archaeology other than just the TV version.

Please could others post about their current jobs or other work they have undertaken.

www.detector-distribution.co.uk

If a job is worth doing, then its worth doing it tomorrow!

Homer (Simpson)

[tom wilson]

I mostly produce reports for old sites that got dug, but for various reasons didn't get written up. I do other bits and bobs around the office too, but I only dig on my 'holidays' these days. I do like to have very long holidays though.

'Have a good plan, execute it violently, do it today'.
General MacArthur

[Steve-B]

That must be interesting Tom, when delving into these old digs, have you come across any major discvoveries/surpises?

Does your job ever lead onto repopening a dig for any reason?

www.detector-distribution.co.uk

If a job is worth doing, then its worth doing it tomorrow!

Homer (Simpson)

[tom wilson]

It might come as a surprise to you Steve, but most people wouldn't touch other archaeologists's old sites with a bargepole. A lot of fieldies don't like writing up their own stuff much, and to be honest a lot of it comprises repetetive, tedious, confusing tasks, stuck in an office all day not talking to anyone. I can't blame people if they'd rather be on site. The really interesting bit, which I should think just about everyone likes, is writing the conclusions and getting to have your ha'penneth about how the site reflects or adds to current knowledge. There's just a lot of record checking, and dull descriptive writing to get through first, and it's much easier if you saw it all coming out of the ground.

It seems to suit me though (for now), and I like knowing that a little article or a monograph or whatever will come out in the end. It can be exciting to break the earth with a digger, never knowing what joys might lie ahead. However, few projects result in big sexy excavations; not much chance for your ha'penneth unless you are senior enough to poach big sites off more junior staff when they find them on evaluations. I also now avoid the kind of bad days that Troll and the like complain about, having to watch as sites get messed up, as will inevitably occur sometimes. I've seen enough. For my stuff, any damage has already been done. I also tired of being the last to see a beautiful green field, and then later of having to work on busy brownfield building sites.

I should add that these are old contract archaeology projects, not grand Victorian enterprises or anything like that. Also, there's no chance of them re-opening, but any archaeologist would agree that non-publication is as bad as the bulldozer. I do sometimes get contacted by people who are preparing to dig near a site that I am shepherding to completion.

[Steve-B]

quote:and I like knowing that a little article or a monograph or whatever will come out in the end <snip> The really interesting bit, which I should think just about everyone likes, is writing the conclusions and getting to have your ha'penneth about how the site reflects or adds to current knowledge.

I can appreciate that..


quote:but any archaeologist would agree that non-publication is as bad as the bulldozer

Quite, or as bad as detecting finds not being recorded.

A couple of digs I have helped out on as a detectorist in the Winchester area were contract digs prior to building projects.

On one of the digs, the only feature was a drove way, other than that it was pretty featureless.

I didnt find this dissapointing though as I found it quite satisfying to know that there was nothing of note there which was a result in itself.

I have top say that I am learning quite alot about what goes in the world of archaeology that I didnt know before, such as your writing up of old digs, I didnt know this was done..

Than ks for your replies.

www.detector-distribution.co.uk

If a job is worth doing, then its worth doing it tomorrow!

Homer (Simpson)

[John Walford]

Steve

In answer to your question about techniques, there are only a handful which are used on anything like a regular basis, of which magnetometer survey is much the most common. In terms of data quality there is little to choose between it and earth resistance survey, as each can give a good overview of most sites; however magnetometer survey is by far the faster of the two to perform.

Magnetometer survey basically measures slight distortions in the earth's magnetic field, caused by the variable presence of iron minerals in the soil. Put very simply, topsoil is more magnetic than subsoil or bedrock, so a deep pocket of subsoil such as an infilled ditch or pit will generate a slight magnetic anomaly (c. 1/10,000th of the total strength of the geo-magnetic field). Burning or firing iron-bearing sediment can enhance its magnetism further, so that kilns, furnaces and hearths can give somewhat stronger responses, as can concentrations of brick or tile. Of course iron objects are much more magnetic again, so buried junk, pipelines, and surface features (fences, pylons, etc) can cause localised interference.

When very large areas have to be investigated there is a technique called magnetic susceptibility survey (or just 'mag sus'), in which measurements are made of the magnetism of the soil at wide sample intervals (typically 10m), looking for broad patches of magnetic enhancement which might mark past areas of human occupation or other activity. Any hotspots which are found can then be surveyed in detail with a magnetometer.

Earth resiatnce survey (which Time Team viewers will recognise as the zimmer-frame technique) works on a different principle. It involves sending an electric current through the ground and measuring how easily it flows. This is largely dictated by the water content of soil, which is in turn often a reflection of its texture and stoneyness. Thus, for instance, a silted ditch cut into a sandy or stony subsoil will often hold an relatively large amount of water and thus appear as a low resistance anomaly. Conversely a large stone foundation will be much dryer and will generate a high resistance anomaly.

The only other technique which is used at all commonly is ground penetrating radar (GPR). However this is not very popular as the equipment is expensive, the data can require much complex processing and the results can be very hit and miss. It is usually reserved for particular situations where the other techniques are not viable and where there is a relatively well defined target to look for (e.g. a classic example would be stone foundations hidden beneath a tarmac surface).

I hope that answers your question well enough. I apologise if its a bit long winded but I'm not always very good at condensing things down.

John

"Hidden wisdom and buried treasure, what use is there in either?" (Ecclesiasticus ch20 v30)

[DAZ 1900]

Very interesting! Many thanks for that John!

It would seem that there is a lot more to Geophysics than i thought there was!!

Obviously Geophysics can/could be seen as the future of Archaeology in it's current format! could you see any future advancements in terms of technology that could surpass the current technology already used?

Thanks in Advance

Darren

[garybrun]

Good question Daz!

http://www.ukdfd.co.uk
Recording OUR heritage for future generations.

[Steve-B]

A very enlightening reply John, many thanks.

I was surprised to read that the GPR is the least favoured method of Geophysics, as I was under the misapprehension that this was the most technically advanced.... I guess a kind of sci-fi perception of it being able to 'see' into the ground.. am pleased to have been put stariaght on this by someone who actually uses the technology.

I have a similar question to Daz.

Which of the methods do you think holds the best/likeliest potential for future development to be able to help negate the need to dig sites, but give the most comprehensive information?

www.detector-distribution.co.uk

If a job is worth doing, then its worth doing it tomorrow!

Homer (Simpson)

[John Walford]

Dear All

When it comes to questions about how geophys might develop, I have to put my hands up at the start and admit that I'm not the best person to answer the question. My background is mainly in archaeology rather than physics or electronics so I can't quote chapter on verse on new technological developments. Having said that, here are a few thoughts for what they're worth.

I don't ever see geophysics developing to a point where it could replace excavation as there are too many things that could only ever be found out by digging. No instrument will, for instance, ever be able to tell you exactly what sort of finds are under the ground, or disentangle the stratagraphy of a deep and multi-phase urban area. I suspect that the discipline will instead stick to the roles it serves at the moment, mapping the layouts of sites so that they can be broadly identified (eg as a barrow cemetery, or an IA settlement, or a roman fort) and so that diggers can make informed decisions as to which areas or features they should target.

New developments are more likely to be about increasing survey speed (to cover larger areas), increasing sensitivity and resolution (so that smaller features within a site can be mapped), and collecting several strands of data together (because types of feature which are invisible to one technique may be shown up by another). I do not expect, in the short term at least, that these changes will come about through entirely new technology so much as by refinements of that which already exists. The biggest change in recent years, for instance, has been the halving of magnetometer survey times by the 'simple' trick of mounting two sensors at a 1m separation in a single hand-held peice of kit, so that a surveyor can collect two lines of data for every one line that he walks.

In terms of new techniques, I think that some of those in use by geologists (eg seismic survey or micro-gravity) will probably not catch on as they are best suited to large, deep targets such as ore bodies or oil reservoirs and cannot, as far as I'm aware, cope very well with near surface deposits. The only technique which I think might become more widely used is electromagnetic survey, which put very simply, alows the collection of magnetic and electrical data without the need to insert probes.

Hopefully that will go some way towards answering the questions that have been put. As before, feel free to ask anything further, although I will not be able to reply again until next weekend.

John


"Hidden wisdom and buried treasure, what use is there in either?" (Ecclesiasticus ch20 v30)

[garybrun]

Thanks John... great info!

http://www.ukdfd.co.uk
Recording OUR heritage for future generations.

[Steve-B]

Thanks once again for your reply John, very informative.

After reading your reply though I got to thinking about something said on another thread in respect of not digging and the policy of leaving sites in situ for future generations, who hopefully will have better technology with which to better interpret the sites.

Do you have any thoughts on which technologies may well be developed to make this capability a reality?

www.detector-distribution.co.uk

If a job is worth doing, then its worth doing it tomorrow!

Homer (Simpson)

[John Walford]

That is a more tricky question as it involves at least three imponderables: 'what technical advances will science make?', 'which of those advances will be affordable to the average archaeologist?' and 'what questions will future archaeologists most want to answer?'. I sat down to try to write an answer but the more I thought about it the more I realised I didn't actually know. I could point to a few existing techniques which I thought might be developed further (eg genetic studies, stable isotope analysis, luminescence dating) and others which would become more usefull as more calibration material was analysed (eg archaeomagnetic dating, or perhaps dendrochronology with species other than oak) but I couldn't actually foresee anything completely new. That isn't to say that there won't be new developments, just that I'm a bit lacking in imagination.

It did strike me though that one reason for leaving some sites for future excavation is that future archaeologists may want to look for things which we don't think are important or which we don't even recognise at present. To give a slightly extreme example, if Mike Baillie's theories about cometary impacts were to become widely accepted (whether or not they should be is a question for another day) then everyone might suddenly start wanting to look for microscopic fallout residues preserved within sediments.

I suppose the only other observation I can make is that I don't believe any amount of technological development will ever completely change the nature of excavation. Ultimately the complexity and uniqueness of every site will mean that it has to be hand dug by people with enough experience to make not only an objective record but also to make subjective decisions about which bits to dig, which samples to take etc. A previous poster in this thread was saying how hard it is to write up somebody elses site without having seen it first had: imagine how much worse it would be to have to write up a site that was mechanically dug by a robot !

John



"Hidden wisdom and buried treasure, what use is there in either?" (Ecclesiasticus ch20 v30)

[Steve-B]

I guess it was a bit of an unfair question John.

I dont think it a lack of imagination on your part but how many archaeologists of yesteryear would have been able to to envisage the scientific methods being used today?

Many thanks for your interesting replies.



www.detector-distribution.co.uk

If a job is worth doing, then its worth doing it tomorrow!

Homer (Simpson)

[easydigger]

nice one David good topic, this is something that at the CLub we are looking at. Main reasons we are very busy with work from private developers last year we did 5 survey including 1 Battlefield. We are only in to March and we have already completed 4 surveys with another battlefield one next few weeks and another 2 surveys pending.

When we are approached by certain companies to do Metal Detecting surveys it is becoming more of a club CV we have to submit to the Council or Company requesting our services. What work have we done? who have we worked for? what type of machines do we use? what methods will we use? have our individual members got CV? what Insurance are we covered by? we aim to put our own metal detecting procedure documents together and do a risk assessment process from metal detecting survey points to hand to the Archaeological services as our box standard process.

http://sargclub.co.uk/Club%20Archaeology%20Digs.html


www.sargclub.co.uk

[BAJR Host]

Ah… you star again…

Loved the page… and will send it to all Scottish Archaeology groups…

As you already know… a procedure/best practice document would be of enormous use to all.. clearly stating the methods, techniques, procedures… etc that can be followed for the work you are doing… (now…. This is where I can play a card.. ;)) call me cheeky…. Call me a chancer… but here is a half thought out – nae detail type thing…

I would dearly love to get this sort of document done, out their, agreed on… edited.. mulled and finalised…. And would be more than happy to publish it via BAJR and promote it… )



A Detectorists Guidance Doc… by Detectorists but useable by Archaeologists to know what to ask for what to expect… AND for Other Detectorists to know what to expect and what can be done plus how to do it.


So here’s my random thoughts… (but as you already know more than me… let me know how it goes)


Definition
Archaeological use of metal detectors will determine as far as is reasonably possible the distribution of metallic artefacts over the specified survey area using the appropriate method and practice. These will satisfy the requirements set out achieve stated aims of the project, whether for prospection, onsite artefact location or scanning of spoilheaps to recover metallic objects.



Potential for Use

Broad categories of use… ( be slightly more specific)
• Road Schemes battlefields and other large areas. (utilise random scanning)
• Trenches (either location of metallic objects within the trench or feature)
• Spoilheap (recovery of artefacts or items from the spoilheap)

Definition of conditions where detecting is or is not suitable
• Field (what sort of fields – moor? Long grass, stubble field, grassland, ploughed field etc)
• Trench (walls, ditches, industrial sites… etc)

What can affect conditions
• Geology and Soil morphology (including compaction)
• Weather (too hot, too wet)
• Depth

Definition of Machine types

• Machine
• Coil/head
• Discrimination
Etc…

Include table where generic machine type is checked against the three criteria A bit like this… but making real sense ;)

Field Trench Spoilheap
Discrimination Depth Discrimination Depth Discrimination Depth
Machine 1 x (Fe) x x x
Machine 2 x x x


Set out the 3 main methodologies

• Random
• Gridded
• Flagged
• GPS
etc….

Have a checklist for decision making

Site type__________________________
Soil Type__________________________
Weather_____________________________
Depth_____________________________
Discrimination__________________________

Machine type required_____________________


Give examples of best practice

Would it be possible to have a flow chart for best machine type?

How to contact individuals and clubs?

Etc


"No job worth doing was ever done on time or under budget.."
Khufu

[easydigger]

cheers David we are working on one at the moment for our CLub Business and box standard survey proceedures, which I believe will be a real step forward into the Metal Detecting Survey process in Scotland esp when we are needed more and more. Keep you posted.

www.sargclub.co.uk