Transcript: VFT 3: Kilmartin Glen - Interview with Dr Richard Tipping, Stirling University

Dr Tipping was asked to describe paleoenvironmental work that he had conducted in the Dun Valley, near Kilmartin Glen. My name is Richard Tipping, I work at Stirling University and I work in a department of Biological and Environmental Sciences. I’m a paleoecologist and a paleoenvironmental specialist. I try and reconstruct landscapes around archaeological sites that archaeologists are excavating, and what I’ll do today is to talk about some work that we published only last year in a valley just to the east of Kilmartin Glen.

This is the valley of the river dun as it flows out past Dunadd. What you’re looking at here is the landscape as it was or is at the present time. We were asked to focus on how this landscape looked at some time in the past probably around circa 2500 BC. There reason all of this work was done was through archaeology found on these small rocks here and one at the far end there [points to rocks in picture]. These are rocks that have been carved or sculpted or engraved by prehistoric people at the end of the Neolithic and the beginning of the early Bronze Age.

This is what the stuff looks like [shows laser scan image of rock surface] – this is one of our rocks, Lion Rock we have called it, the other was called Tiger Rock. And what you see here is a laser scan of the rock art, the carvings that were put on the surface of this. Some of these are really quite hard to see, particularly in daylight but the laser scan brings out all the detail. And you can see that they vary in complexity. There are simple cups, little hollows ground into the rock, and then you get more elaborate versions: of a cup and a single ring and over here a group of a cup and several concentric rings and they’re scattered over this outcrop of rock. The project we had was never really to explain what was going on here, because there are many interpretations of why people carved rock art and why people made these particular carvings, but our concern was with the landscape context.

We had a series of research questions. These are the research questions that we were asked to answer by the archaeologist Andrew Jones at Southampton. He wanted to know whether the rock art on the rocks were hidden, perhaps known about to only a few people – an elite – in late Neolithic society. Or, did people visit them? Did people embrace them and place them in the heart of their world? Now, by heart of their world we basically meant is this a farmed landscape or was this wild? Was it somewhere nobody went or was it known and appreciated and admired by all? So, how easy was it to reach the rocks? What did you have to do to get to the rocks to see the rock art? Some people would argue that it’s a challenge to get to these rocks. We know of stone quarries in the Neolithic which appear to be deliberately placed on very steep almost inaccessible rock outcrops as if part of the winning of that rock was a challenge, it was an achievement. And then of course, where were the rocks two and a half thousand BC? What did the valley floor look like? There’s a river on the valley floor, where was that? These are all questions you can answer using paleoenvironmental investigations and the investigations we applied to this area, to Torbhlaren just to the east of the Kilmartin Glen, encompassed pretty much all the techniques we can apply to an archaeological landscape.

So, we had to map out and understand the ales of landforms and features; we had to describe the land use, if there was land use; was it full of wood; were the trees the same as they are now; what was happening to the valley side, could we see evidence of people working these fields?

File Ref: D:\Docs\2018-04-06\08f3db710e7bf4f9865257ee65b70e53.docxPR029 Web: http://www.uhi.ac.uk/learning-and-teaching  [email protected] Content: Page 1 of 6 Transcript: VFT 3: Kilmartin Glen - Interview with Dr Richard Tipping, Stirling University 26/02/133 This is a spoiler [shows reconstruction image] because this is what we ended up with. This is the same picture you saw first of all but now taken back to the 2400 BC. What I’ll try and do is go through all the thinking and all the evidence that went to construct this. Effectively, we can explain and justify everything here in this photograph; ironically, however, not the archaeology up here [points to top of picture]. There’s no evidence of the [settlement]. We put these round huts, these hut circles, on the slope by and large because we have evidence for soil erosion and I’ll talk about that in a minute.

So, first of all, here is the valley floor; here is lion Rock and further up, there’s tiger rock. And when both of these were being carved there was a single standing stone which you can see up here. This standing stone should be much earlier than the rock art on these rocks, perhaps a thousand years, or more, earlier. So we’ll go through the process to reconstruct this landscape in the way we have.

The first thing we had to do was to try and find out what the flood plain, the valley floor, looked like in 2500 BC. Here is an aerial photo of the part of the valley we worked in. And here is the river Add at the moment. It is locked, it is right on the Northern side of this East-West valley and it has been locked into bed rock at the side there. There’s no evidence of meandering of that particular rock. Down here we see evidence that this stream has been altered and shaped by people, probably 200 to 250 years ago as they tried to constrain the river but our question was: where was the river when the rock art was being carved, when these outcrops were being used for the engraving?

Well, these shadowy features that you can see here are former channels of the river. Most of them are the same size as the river of the present day and from that we can probably imply that the river was the same size and the same width, and carrying the same amount of water as it did then.

Fortunately, being on the west coast, most of these channels are now filled with peat. This is the stuff that you see filling these channels. And, we can radio-carbon date the base of the peat as it lies in these channels. And this is what these dates [shown in photo] relate to. This channel appears to have been abandoned by the river at just after 6430 calibrated BC, so that’s well into the Mesolithic before the Neolithic period. The way you interpret radio carbon dates in these channels is simply to think that peat couldn’t grow in these channels when the channels were full of water and were the course of the River Add. But once the river moves, or jumps out of that channel then the peat starts to form very quickly. So these are telling us about the times when the river moved to a different channel and we can reconstruct a kind of a sequence of events if you like. This oldest channel here [6430 cal BC] is traced through to this point; another radio carbon date says that the river left this part maybe a thousand years earlier [7400 cal BC] than up here. Again, the same valley, the same channel and this component was dated very close to this one [points to 7250 cal BC marker]. So we have a single channel that stayed on the south side of this valley not on the north. This river has jumped – probably very rapidly – sometime after 2400 BC. This [points to south side of valley] was the route, the main channel, when the rock art was being used. And quite by luck this channel [points to darkened line on aerial image], this thin stream coming in here, is dated to 2425 cal BC which is the date that we think the rock art is being created. So we do know that at that point the water was on this side. As I mentioned before, if you prod around in these peat-filled channels you get a feeling for the shape of the channel itself: was it deep? Was it multiple-threaded? These parallel channel sections here might suggest that all of these channels were occupied at the same time that you had more than one channel but we don’t think that’s right. Each of these was occupied sequentially.

So a single channel, no deeper than the present time, which is less than a metre really and a river no wider than that. So our first question was almost answered. To get out onto the valley here to look at these rock arts, these engravings, was no problem at all. There were no deep rivers, no mighty chasms that they had to get across. It was ordinary to get there [points to Lion rock location].

File Ref: D:\Docs\2018-04-06\08f3db710e7bf4f9865257ee65b70e53.docx Web: http://www.uhi.ac.uk/learning-and-teaching  [email protected] Content:: Page 2 of 6 Transcript: VFT 3: Kilmartin Glen - Interview with Dr Richard Tipping, Stirling University 26/02/133 So that kind of allows us to work out how the valley floor was created. From these radio carbon dates we can tell that these things were in the middle of the valley as they still are now. We know that this was the edge of the valley when these [rock arts] were created. And we know, or we think we know, that the river was not over there, always over here.

So, that’s the landscape itself, that’s the physical landscape that was there. The next thing we were asked to do was to try and understand what the place looked like in terms of the vegetation, in terms of possible land use and for this we have to use a second, more important technique or certainly more widely used technique, that of pollen analysis. I’ll keep this map [aerial view of valley site] here just for a moment because the site that we chose to do pollen analysis on is unusual in one respect. We chose to core this thin channel here [points to map showing location dated at 8125 cal BC] the date on the earliest peat in this channel is 8125 cal BC so again this channel was used and then abandoned, perhaps the river swinging over here, in the Mesolithic but the peat accumulated through the Mesolithic into the Neolithic and in fact it goes all the way through to the early Iron Age about 800 cal BC. So we have a record of peat accumulating in this channel over several millennia but the key thing is the narrowness of this channel. It’s about 5 paces to go from one side to the other. It’s a very thin streamed channel. Why is that important? That’s important because channels and peat sequences as thin as that are in very close contact with surrounding dry soils. So, we can define that the pollen arriving in this channel only comes from an area very small around that channel. So, we are looking at the flood plain, we are looking at these lower slopes [south side of valley] and we’re not looking at what happened to the trees or the land uses tens of kilometres away, these are local pictures that we are creating.

So, what is a pollen diagram? This thing usually puts people off; I’ve tried to make this slightly simpler by giving the names in English of a few of the things we’re recording. So how does pollen work? Pollen works with several assumptions. First of all it makes the assumption that pollen grains look different and that pollen grains of particular trees or particular herbs or grasses, look different to other trees or grasses or herbs. That’s true to an extent but not entirely, as I introduce these things to you.

‘Alder’ is a tree known as Alnus glutinosa. It’s the one tree (it’s the one Alder species) that we find in Britain today. There are two species of ‘Birch’; we can’t tell the two species apart. ‘Hazel’ is fine because Hazel is a single species, Corylus avellana. Again, ‘Oak’ – there are two species, we don’t know which this was. This is perhaps the most difficult of the taxa, the types that we record: it is here ‘Wild grasses’. There are hundreds of wild grasses in the British Isles and they all look the same when we look at the pollen grains. However, next to wild grasses are ‘Barley’ and ‘Wheat’. They are both grasses. A third grass is ‘Rhye’. We only found barley and wheat. How do we know that these are barley and wheat and not wild grasses? That’s because barley and wheat are grasses but they have a shape which is much much bigger than wild grasses so these are very large grass pollen grains. And we can tell barley from wheat, again from the size of the grains and particular features on the pollen grain. The other two taxo that I’ve used here is a plant called Ribwort plantain. That’s pantogo lanseolata, and plantago lanseolata is a very good indicator of human activity. It tells you that the vegetation is being altered and probably altered by grazing animals as the woodland declined. And ‘Bracken’, bracken can grow inside hazel and oak and birch woodlands. It also flourishes when you take these trees away. So bracken, again, is an indicator probably of open ground.

So, the pollen diagram, what do these lines represent? Each of these bars that you see is a particular slice of sediment thin (only a quarter of a centimetre across) that the pollen analyst has taken out from a pollen core. Over here we see the depth of this pollen core. It’s only 95cm deep and here it goes in 5cm increments up to 20cm from the top. We can understand the chronology of this peat sequence from these over here. These small squares represent samples of a centimetre thickness which we submitted for radio carbon dating. What you see over here is the age range in calibrated BC of these small bits of peat. So, the age range, here: 7970 – 8280 calibrated BC. And we took dates all the way up. From those dates we can

File Ref: D:\Docs\2018-04-06\08f3db710e7bf4f9865257ee65b70e53.docx Web: http://www.uhi.ac.uk/learning-and-teaching  [email protected] Content:: Page 3 of 6 Transcript: VFT 3: Kilmartin Glen - Interview with Dr Richard Tipping, Stirling University 26/02/133 construct a general pattern for how this peat has accumulated and so the second column here is the age in 500 year slices so we can know the age of any of these individual analyses. So then the pollen analyst starts work and this diagram is the result of something like three or four months solid work looking down a microscope. For each of the analyses you count many hundreds of different pollen grains. This was constructed from a total number of pollen grains counted of about 300.

If you count 300 pollen grains in one level you get a good representation of what’s there. It’s a typical sample, you are describing the landscape. Each pollen grain of these 300 is identified to a particular taxon and then the levels are added up and constructed on this diagram here, so we are describing vegetation change and we’re describing land use change from 8000 BC through to 500 AD. The arrow indicates the important horizon here which is what the archaeologist was interested in. This line across here, around about 2400 BC, is when we think the engravings we made on the rock art.

We have though a picture of how this landscape changed, from much earlier. So we see a hazel woodland and birch coming in. we see that oak colonises after hazel and birch but when oak arrives hazel and birch start to decline. Oak competes successfully with birch and hazel and can push these things out into the margins of our landscape. And alder arrives here, quite slowly and alder will occupy the ground around the stream channels, growing on and around the peat that we’re seeing. That’s one reason why there’s so much alder: 60% because our pollen site which you saw probably had alder growing on it. So we’re looking out, as it were, at a landscape through a cover of alder and we’re glimpsing the dry woodland of oak and hazel and birch and we’re seeing the land uses as they start to appear. So these wild grasses start to appear around here: 4500 BC. That’s still within the later Mesolithic. And the increase in wild grasses is probably a result of something in the late Mesolithic affecting the woodlands. There’s more open space and more room for wild grasses. This is probably some clearance activity. As the grasses expand, look across and you see alder declining steadily. So alder woodland was being cut down probably on the valley floor and wild grasses appeared. And wild grasses never then disappeared. They are consistently represented. From this point, 4500 BC, we have land use – a landscape used by people; used by people after 4200 BC by pastoral farmers – people driving cattle through. And then, shortly after, from 4000 BC, small indications that barley was grown and then wheat was grown. And by the time the people carving on the rock art were here this was a valley that was used in a full agricultural sense.

We can, to go back to my first picture, start to paint a picture of the land uses. The valley floor, we think, was probably used for pasture and it was probably grazed by cows, rather than sheep because cows graze grass differently to sheep and there are particular species that can cope with cattle grazing which can’t cope with sheep grazing. So here they are, roaming free on a treeless valley floor. On the slopes we argue that the crops, the barley and the wheat were being grown up here. The reason we think that is because we know that when the rock art was being engraved, at around 2400 BC, the valley floor was receiving larger floods (the river was more active than it is at the present) and could flood the flood plain periodically. So, keep the cows down here and move the crops up onto the slopes where they’re protected. And while we’re looking at this landscape two other features: the first is that the hills that you see behind us are still fully clothed in oak and hazel woodland. We have a second pollen site way over the hill here, a pollen site which is detecting the landscape in the uplands and apart from a few cows wandering through here not much was happening; everyone was happy to focus on the valley floor and these very productive slopes. And of course, as we’ve discussed, the engravings were easily reached across here. So we can reconstruct what this place looked like from something like a pollen diagram.

In this study we thought we could go one further than just painting a broad picture. We thought that because of our pollen site being so small we thought we could actually try and place where these trees were around that pollen site.

File Ref: D:\Docs\2018-04-06\08f3db710e7bf4f9865257ee65b70e53.docx Web: http://www.uhi.ac.uk/learning-and-teaching  [email protected] Content:: Page 4 of 6 Transcript: VFT 3: Kilmartin Glen - Interview with Dr Richard Tipping, Stirling University 26/02/133 This rather ghastly looking picture shows you how we tried to do this. The top left we have ‘x’ marks the spot; that is our pollen site. And we think that all the pollen arriving at that pollen site was from that area around here. That area is defined in these squares here. We know the species, or the taxa, that were growing here and we can identify different land uses or vegetation types down here, these are the areas of land use. And what we can do, through something called simulation modelling is to try and reconstruct where these different plant communities could have been at the time. We know how much pollen of upland woodland species there were or of pasture we know the species involved. If we also know how far away from the parent plant these trees or herbs spread their pollen, we can then confine these different plant communities to different parts of the landscape. So these gaudy colours are the computer generating, overnight, different scenarios: do you want me to put all the bare ground here or would you like me to put bare ground, very patchy, across the flood plain? Do you want me to put these trees, the dry woodland, across the flood plain or shall I confine them to the valley slopes? All of these are feasible, so we can’t really tell which of these scenarios was the best one. But since we know how the flood plain responded to floods, and how the slopes responded to soil erosion, we felt that we could place our plant communities in different parts of the landscape. So the picture is valid, we think.

One final technique that we employed here at Torbhlaren, we know how the river responded and how the river operated. We know what the pace looked like in terms of its vegetation and we know that it was being used for growing crops and barley from early in the Neolithic. We also found particular sites that could tell us about the erosional history of the valley sides themselves. This again is a diagram, it is not however a diagram of pollen types but now of the sediments accumulating in valley side locations. I’ll show you where these valley side locations were in regard to the picture at 2400 BC.

So here we are. What we’re trying to reconstruct is what these slopes looked like. Running along the bottom of the valley are thick peat sequences. They started to accumulate in the Mesolithic because this is where the river channel was. When the river jumped to different areas of the flood plain then the peat starts to accumulate and the peat continues to accumulate, and it continues to accumulate even though sediment and soil is washing down these slopes into these peats. So it’s those areas of slope wash and soil erosion; and here [points to slope in picture] the formation of a deeply gullied alluvial fan coming from this high ground up here and spilling out across the flood plain here. How did we get to these?

Well this is how we do it: we take a sediment core. This [points to diagram] is the depth again, these are our radio carbon dates and this is our timeline from close to the present day back here almost 13000 years ago, way earlier than we need to worry about. The analyst here has sampled and measured two things. The first thing he has measured is the carbon content by loss-on-ignition – you take a slice of peat or peat with sediment and you effectively set fire to it at 550°c. What you do in setting fire to that is burning off the organic matter so what’s left is the mineral residue, the silts and the sands and the clays. And you can construct a curve of carbon content.

When the carbon content is high, there’s a lot of peat and therefore very little soil erosion, this typifies this zone [points to area of diagram at bottom left of screen] in the early Mesolithic. But each of these wiggles and curves here marks a period when soil was washed into these peats and these are particle sizes [points to central part of diagram]. Only the coarse sediments here, the sands, and the gravels and what you see are fluctuations in these things. Sometimes there’s coarse sand and gravel being washed down – these need more energy than fine sand or silt. So when you see very coarse sand, then there is something very violent happening on the slopes above the flood plain. So we can tell a story here about how the slopes changed and how the sediment as washed down.

So finally, back to our picture at 2400 BC: a very busy agricultural landscape with these rocks and the rock at very familiar to people living up here on the slopes. They could perhaps visit whenever they wanted to. This rock art was being shaped in particular ceremonies however. The rock art was being carved. There

File Ref: D:\Docs\2018-04-06\08f3db710e7bf4f9865257ee65b70e53.docx Web: http://www.uhi.ac.uk/learning-and-teaching  [email protected] Content:: Page 5 of 6 Transcript: VFT 3: Kilmartin Glen - Interview with Dr Richard Tipping, Stirling University 26/02/133 were platforms built where the rock art engravers stood and worked. Andrew Jones at Southampton has found the hammerstones and the scrapers with which these people pecked the rock. We have evidence that colour was used in this rock art. Patches of red ochre were found at the bottom of these things. And also possibly the carvings were being created at night, certainly with the use of fire to illuminate what was happening. So these were special places but in a well understood and well-used landscape. The soil erosion because the crops they were growing were not in fields as we would recognise them. There were no field boundaries or hedges or walls. So if you grow crops, you will lose the soil and it will fall down. So over time these soils become less successful at growing crops but by the early Bronze Age/late Neolithic. These people also lived by natural gullying and natural sediment erosion. That’s probably triggered by climate and climate deterioration. So soil erosion up here is not simply the fault of the farmer they were also battling with a changing climate.

The trees we’ve talked about; this patch [far right] we haven’t. This is a patch of oak woodland. This is very strange and has got us very excited indeed. This patch of oak woodland wasn’t there in 2900 cal BC. It started to grow; no species other than oak grew in this woodland. At 2400 BC, when they were carving this, somebody decided to cut down all the oaks in this area. So after 500 years, trees which were by then very large, very massive timbers, were cleared. We don’t think this is for building. At the same time people were incorporating large oak timbers into lots of ceremonial monuments in the Kilmartin Glen itself. This may have been a conserved woodland that was then used at the right time - quite an extraordinary concept.

So this was Kilmartin, or the valley near it, as it was in 2400 cal BC.

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