A day-by-day account of the activities of the Rossnaree Archaeological Project 2010-11

Posts tagged “archaeological techniques

Day 19 – It is all becoming clear now…

First of all, the piece that RTE came to the site to film was aired on the 6-One News and the 9 O’Clock News on RTE1 last night. It is amazing how much time was spent on-site and how much footage was shot to make up the final piece. I think the point was well made, however and thanks to Chris in the Institute of Archaeologists of Ireland (IAI)  for setting up the piece and to Philip Bromwell for his interest and patience. For those who didn’t see the piece, the link is:

http://www.rte.ie/news/av/2011/0727/media-3012820.html
Cut 8 cleared at last!

Anyway, back to business at Rossnaree. There was prolonged rain overnight which thankfully had cleared by morning. This moisture did wonders in each of the cuttings because suddenly there was, once again, some colour in the soils. Instead of a continuous hard-packed dusty pale yellow surface like concrete, we could see all shades of brown, orange, yellow and even red. At last we had some clarity and we able to distinguish between the last skims of ploughsoil and the undisturbed natural. If only this had happened a week ago it would have been much more helpful, especially in Cuttings 7 and 8 where had such difficulty. That’s the way the breaks come – all real discoveries inevitably seem to come in the final week of the dig (remember what happened last year!) or, worse in the last day or two.

Sieezing the opportunity presented by the conditions, Darren, Sophie and Ciara trowelled over the surface of Cutting 8 one last time to reveal a number of disturbed areas which are probably the remains of additional graves in the cemetery. At this late stage of the dig it is not feasible to excavate further but we at least have been able to identify and record the location accurately. All of the new detail was added to a plan of the cutting later on that afternoon.

Kieran to the rescue!
Matt planning again.

In Cutting 7 we were joined by Rossnaree veteran Kieran Campbell who was a member of the team from last season. Kieran very kindly offered to help out in the last few days of the dig – exactly the time when he is needed most. Kieran undertook to lift the skeleton in Burial 2 along with Matt. Mags recorded a number of the features that Matt had previously examined in the cutting by drawing sections and profiles of them. Matt later finished drawing the post-excavation plan of the cutting and he added the detail of the grave cuts. When this was done he drew up the southern section face of the cutting showing the depth of ploughsoil and the various levels within it. Kevin was also on hand again today and using a total station he accurately recorded the positions of the control points we had installed around Burial 2. He also surveyed in the location and shape of each of the grave cuts of Burials 1 and 2.

In Cutting 6 Eimear carried out post-excavation plans of the two completed sections and also drew up the profiles of the sides of the cuttings. Niamh continued to excavate a section through the oval enclosure ditch and this is turning out to be quite a substantial feature. It is a lot deeper and wider than we had anticipated but she has found the edges on either side as well as the base. Very good work for one day.

Tomorrow, we will finish the last of the recording and then start the backfilling. I’ll let you know how we get on.

Nearly there…
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Day 16 – The pressure’s on.

We are now into the final week and there seems like so much still to be done. At least the weather is holding up. It was not as sunny as it was over the week end – the day started out a bit overcast with a few drops of rain as well, but very calm. As the day wore on the cloud cover thinned and although the sun didn’t come out fully it was quite a warm and pleasant day.

Mags and Ciara in Cutting 7

In Cutting 7 Lisa and Ciara continued the final clean-down of the surface to make absolutely sure that there are no further features there. Matt started work on lifting a piece of cranium we had noticed on Friday in the south west corner of the cutting, a little distance away from the grave cut. We had assumed that this was a fragment of bone disturbed from another grave but as Matt cleared more it became apparent that there were several pieces of bone in situ within the fill of yet another grave cut. This, of course, is not surprising because we already have found one grave, but it is not something we had planned, or hoped, to find. The work in this area will now slow down again considerably as the grave is carefully excavated and recorded. This is time we can’t really afford at this late stage.

Human bone fragments and another grave cut.

Matt bags up some of the bone.

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Darren working on his section.

Eimear's ditch section today.

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In Cutting 6 Eimear and Darren continued work on their respective sections and both were successful today in finding the western edges of the cut. In each case the edge was cut into quite gravelly material, very similar to that identified in the base of the ditches excavated last year. Ash, animal bone and charcoal are all frequent and at Darren’s end, there seems to be a lot of flint while at Eimear’s end there is an interesting socketed iron object, probably a tool of some sort, sticking out of one of the layers. Kevin had identified this as a location of some potential last week when he scanned the cutting surface with his metal detector. The next step is to identify the various fills visible in the vertical section face of each mini-cut and then to photograph and draw them up.

In other news, we had a visitor today from RTE television – Philip Bromwell – who is doing a piece on how the archaeological profession in Ireland is faring in the current recession. This was a suggestion made by the professional body for archaeologists in Ireland, the Institute of Archaeologists of Ireland (IAI). As well as filming the dig in progress and speaking about the stages in the research process leading up to the excavation, there was discussion of the many archaeologists who had been working in the profession who are now unemployed. There was also some talk about the severe cuts in various research funds available for archaeological research like the Heritage Council’s discontinued Heritage Research grants or the INSTAR grants. The piece will hopefully air on the 6 One News later this week. I’ll let you know…!


Day 15 – Summer’s back!

Well, who’d have thought it? Met Eireann, the Irish weather service issued an apology for the weather forecast for yesterday. They said there’d be occasional showers in the east of the country (where the Rossnaree excavation is located) but instead there was virtually continuous grey wet drizzle for much of the day. You have to take the rough with the smooth – normally when the forecast suggests that there might be showers or rain, I have found that we have a good chance of being lucky. The rain takes a little bit longer to get across the country to us in Rossnaree and we usually seem to escape the worst of it. To have the opposite happen once is, I think, acceptable because of the number of escapes we have had over the last few weeks.

Ciara cleans Cutting 7.
Excavating the human remains.

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The weather on-site was perfect – bright spells and cloud, not too hot, and no rain of any sort. Everyone was in a good mood (I think) and there was an air of quiet industry over the site for much of the day. Ciara was working single-handedly in Cutting 7 for the morning giving one last clean-back to the exposed surface there to make sure that no possible features had been missed. After lunch, Matt did a plan of the grave again, detailing the position of each of the bones and we spent the afternoon excavating, lifting and carefully packaging each bone. Each piece was numbered on the plan and photographed and wrapped and labelled for storage and later study.

Mags and Sophie clean back Cutting 8.

Mags and Sophie continued to take down the last of the disturbed layer of soil overlying natural in Cutting 8. Despite the rain the previous day, the soil was drying out very quickly making the identification of the different colours difficult. The layer closest to natural has quite a mottled appearance – it is a mix between the compact yellowish natural and ploughsoil and has frequent worm holes through it. There are still occasional flecks of charcoal and occasional fragments of bone so we are certain that the surface is definitely not natural. Hopefully we will be finished in this cutting very soon.

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The needle in situ.
Eimear displays the needle.

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In Cutting 6 Eimear continued to dig the section at the southern end of the cutting and a number of interesting finds came up. Below the upper layer of charcoal rich soil there is a thick deposit of almost pure ash and within this there is a deposit of animal bone, probably cow, including a mandible (jaw) and rib, among others. These seem to have been deliberately deposited with a number of burnt stones (one of which Eimear named ‘the raspberry stone’ because of it’s vivid colour!) and also an intact bone needle/pin. This is definitely find of the week and although it can’t be closely dated, it definitely belongs to the early medieval period. The Neolithic remains elusive.

Darren’s ditch section so far.

We set Darren up at the northern end of the cutting doing a similar section to Eimear across the ditch. We seem to have clear edges to the ditch feature with natural visible on both sides. Again, the fill is very rich in charcoal and ash and the edge of the cut of the ditch is quite steep. There was still no sign of the base of the ditch cut in the evening when we were finishing up. Flint artefacts were frequent but it is not clear whether they are indicating a date for the digging of the ditch or whether they were disturbed and incorporated into the fill of the ditch during the early medieval period. Lots to look forward to on Monday.


Day 11 – A new week.

Igor tests his trowel.

We’re over the half-way mark now and beginning to think about making sure we are able to finish everything we start in the time available. We were joined by a new person this morning for a few days – Igor – who was involved in the geophysical surveys of each of the areas immediately prior to the start of the excavation. While Igor now works mainly in geophysical surveying, he has spent time on a number of the Celtic Tiger road schemes and his experience is welcome.

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Matt and the ‘mystery feature’.

The weather over the week-end had been quite mixed with a lot of showers. This was good for the site because when we arrived down and took a closer look at the cuttings, the additional moisture in the soil has made it a bit easier to see the differences in the colours and textures of the soils making up the fills of features. In Area 2 Matt continued to examine features that were identified and planned last week. He did this by half-sectioning them. This is where half of the feature is excavated using a trowel or a leaf trowel to find the exact extent and the cut and base of the feature before excavating and removing the second half. This usually means that the excavation of the second half of the feature is more accurate and ensures that any soil samples, which are only taken at this stage, are less likely to be contaminated with other soils. These soil samples can later be processed to identify macrofossil remains, i.e., fragments of vegetation etc. which, in turn, can tell us about the environment around the site at the time the feature was in use.

Most of the features that we had identified turned out to be less than exciting. Many seem to be pockets of soil that had accumulated in deeper-than-usual hollows left in the subsoil where large cobbles were disturbed by ploughing. However, there is one area where there may be a substantial feature containing a number of fragments of bone. We have labelled this Feature 714 and we will take a closer look tomorrow before coming to any conclusions. I’ll keep you posted.

Darren ‘The Machine’!
Sophie on the sieve (again!).

Darren and Sophie continued to take down the ploughsoil in Cutting 8 and this was almost completed by finishing up time after a burst of very robust mattocking by Igor. Once the cutting clear, we will work it back again to find the base of ploughsoil in the same way as we did in the other cuttings. However, this process should be a lot quicker this time because we have a very good feel for what the local subsoil looks like and at what depth we should expect to find it.

Eimear’s the boss!
Area 1: ‘you could eat your dinner off it!’

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In Area 1 the cleanback continued in preparation for photographs and planning. The whole surface of the cutting had to be troweled over lightly again because a certain amount of dust and other debris had blown in over the week-end and the rain had made the surface less clear and distinct. Eimear was in charge and by the afternoon, the photos were taken and the planning could begin.


Day 6 – Moving up a gear.

Magnetic gradiometry, Area 1.

We all arrived down to the site hut revitalised, reinvigorated and ready for the new week. We were close to being completely free of the monotony of mattocking, shoveling and sieving through ploughsoil, although the finds we are coming across are nice. In Area 1 at the start of the day there were still 10 square metres to be dug away and throughout the day the team there got through seven and two half squares. Tomorrow, there are only two half-squares and one full one to go. Once they are gone, we will be nearly ready to begin to search for the features identified in the geophysical surveys carried out by Kevin before the dig started up. In the plot the cutting itself is made up of columns G, H and I and extends from row 1 to row 10. This takes in two very distinct features: one, a possible ditch running from north to south (from previous geophysical surveys this seems to be the innermost enclosure defining the knoll of high ground) and the second, at a higher level and cutting the other feature curving in from the middle of the right side to the bottom of the panel (this seems to be a separate oval enclosure superimposed on the other ditch. See the original plot HERE). This cutting will investigate the exact relationship between these two separate features and hopefully will yield material for dating.

Lisa, Mags and Sarah.
Sophie on the sieve.
Darren gets to trowel.
Magnetic gradiometry, Area 2.

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In Area 2, they started the day with just two metre squares to go and these were quickly removed and sieved. Once this was completed, we took another series of soil samples for lab magnetic susceptibility measurements using the same grid as before. Thus we will be able to compare values taken from the field surface to those at the base of ploughsoil. Once this was done the cutting was ready to be troweled back. There was still a layer of ploughsoil over the cutting – we deliberately didn’t remove everything when we were mattocking off the ploughsoil partly to protect the site from being open too long and from the impact of people crossing over and back as they work. Trowelling, with the help of some light mattocking where necessary, is the next step taken to remove any remaining layer of disturbed ploughsoil and begin to identify the features underneath. We are lucky in that we have a very detailed set of geophysical plots to guide us as to what to expect. However, the picture here is less clear with a series of features that are unfortunately less identifiable than those in Area 1. The excavation here is to explore the nature of these possible features – our hunch is that they may be houses because of their location within the innermost enclosure on the highest point in the site – but we will be scratching our heads if we don’t end up finding the features indicated on the geophysical plots. The cutting itself measures 5m x 4m and is located between squares Q10-13 and U10-13 although this will probably be extended southwards at a later stage.

Eimear searches for the feature in square U13.
All hard at work in Area 2.

Day 2 – Now the digging begins

Matt cuts the first sod of the season.

Having successfully taken all of the soil samples from the ploughsoil surface for later magnetic susceptibility analysis there was nothing further to delay actually getting stuck in and doing some digging. We set out each cutting – Cutting 6 in Area 1 and Cutting 7 in Area 2. We are continuing the trench numbering system from last year to avoid any overlay or confusion in the archive. Cutting 6 measures 10m x 3m and is orientated north-south while Cutting 7 measures 5m x 4m.

An interesting find turns up in the sieve.

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The ploughsoil in each cutting is being taken down first using mattocks and shovels and the spoil is being sieved for artefacts. This is being done on a metre-by-metre basis so there is spatial control on the artefacts retrieved. Although the ploughsoil is a disturbed context and a very dynamic layer, there could be a relationship between the material ‘floating’ in the ploughsoil and the features beneath it. We are recording the spatial locations of the artefacts anyway and hopefully in the final analysis patterns and relationships will emerge.

The Area 2 sieve

Mags and Jamie using the Area 1 sieve.


Geophysical Survey 2010

Following the surprise development in the excavation last year where it was conclusively established that the enclosures on the site are likely to be early medieval in date (and probably between 7th-11th century AD), it was decided to carry out further geophysical survey over the core area of the site on the top of the knoll within the tillage field. This was clearly a focus of activity in prehistoric times because of the extensive lithic (flint) scatter found there. It also seems to have been a focus during the early medieval period as this is the area central to all of the enclosures.

Because of the lithic scatter, this area remained the best candidate area for identifying prehistoric activity. However, because of the apparent intensity of activity in the early medieval period, there is a chance that any prehistoric features that may once have existed are completely destroyed and disturbed.

With these problems in mind, a second programme of geophysical survey was carried out in August 2010 at a higher resolution than the original geophysical surveys. The hope was to identify more clearly any features that might be earlier than the early medieval enclosures. Three high resloution surveys were carried out: magnetic gradiometry (Figure 1), earth resistance (Figure 2) and magnetic susceptibility (Figure 3). See the following figures for the results of each of these.

Figure 1: Detailed magnetic gradiometry plot with topography, August 2010

The magnetic gradiometry has shown up more detail than was apparent on the original survey. For example, the second enclosure from the outside clearly deviates from its curvilinear path as we move northwards towards the terrace slope. This may be a modification of an earlier version of the enclosure as there are hints of an earlier, less definite enclosure continuing northwards. The other feature of interest is the relationship between the inner complete oval enclosure and the D-shaped enclosure beneath it. The oval enclosure looks like it cuts through the other enclosure and thus is later in date. Furthermore, there is a difference in the quality of the magnetic response between the two features suggesting that they are constructed differently. The oval enclosure is more similar in the character of its response to the other, outer, enclosures. There seems to be a contrast between the innermost D-shaped enclosure and the rest of the enclosures, possibly suggesting different construction techniques which may be due to their being constructed at different dates. Clearly, the innermost D-shaped enclosure is earlier than the oval one. The question is how much earlier. Are we looking at a possible prehistoric enclosure?

Figure 2: Detailed earth resistance plot with topography, August 2010

The contrast between the different enclosures noticed in the magnetic gradiometry is replicated to some degree in the earth resistance plot in Figure 2 so what we are seeing is likely to be real and reflect the real character of the features themselves. The innermost D-shaped enclosure is almost invisible on this plot, especially along its western side. At the southern end of this inner enclosure feature there is an area of high resistance with a sharp delineation between the high-resistance (light coloured in the plot above) inner area and the low resistance area immediately outside (dark coloured). The junction between the two areas appears to be particularly sharp and suggests a possible stone facing/revetment feature.

Figure 3: Detailed magnetic susceptibility plot with topography, August 2010

The magnetic susceptibility plot shows an area where the soils have been strongly altered by activities like burning and the disposal of organic waste. It shows a clear and distinct focus of activity which seems to be contained to the west by the third enclosure from the edge. It extends a lot further to the south than the line of this ditch and continues on outside the survey area. There is a band of low values running in a north-south direction through the middle of the zone of enhancement which may be due to the way the space was utilised in the past, or it may be due to sampling or post-depositional processes. There seems to be a slightly separate elongated area of enhancement running east-west along the northern boundary of the field which may be a secondary activity focus. It may be significant that this is focused on the southern side of the highest point of the topographic knoll.