Analysis of a Neolithic stone axe

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Aerial shot of Carnoustie Neolithic Hall – the axehead was found near the top left centre of the hall

Buried within one of a row of pits within the large Neolithic hall at Carnoustie was a complete axehead in pristine condition, quite possibly never used. Measuring 170 mm long and 63.5 mm wide, this was analysed by Alison Sheridan from National Museums Scotland. With one face more markedly convex than the other (the blade lies closer to the less convex face), in theory this could have been hafted as an adze-head instead of an axehead, although it lacks the marked longitudinal asymmetry of adze-heads.

Neolithic stone axehead

There are numerous shallow striations all over the surface, from its grinding smooth and polishing to a low sheen. There is no obvious haft stain, and in any case the position of the axehead in the pit indicates that it was unhafted when deposited. The stone has kindly been identified by Dr Peder Aspen (former curator of the Cockburn Geological Museum at the University of Edinburgh) as a garnet-albite-schist, a metamorphic rock originating in the Highlands.

Finding the Neolithic stone axehead

Stone axeheads were an essential tool of farming communities, and many will have been required in the construction of the large Early Neolithic timber buildings at Carnoustie. It is possible that the deposition of what appears to be an unused axehead in a pit was a symbolically-significant act for the Early Neolithic household here.

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Comparing the Carnoustie and Pyotdykes spearheads

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the Carnoustie spearhead

The Carnoustie spearhead was probably the star find of the dig. But it’s not the only gold decorated bronze spearhead to be found in this part of Scotland.

 

 

Pyotdykes spearhead © The McManus: Dundee’s Art Gallery and Museum

Another Bronze Age hoard was recovered at Pyotdykes farm just outside Dundee in 1963 and it too includes a gold decorated bronze spearhead. Indeed the discovery of the Carnoustie hoard spurred one of the specialists involved in our post-excavation programme of works, Alison Sheridan of the National Museums of Scotland to re-examine the Pyotdykes artefacts – two swords and the spearhead – which are held by The McManus – Dundee’s Art Gallery and Museum.

details of gold decoration of Carnoustie spearhead socket

Though a different shape to the Carnoustie spearhead, it is again the socket of the Pyotdykes spearhead which is embellished with a gold strip. The decoration on the Carnoustie band is decorated with a herringbone design between zones of two to three concentric lines,

detail of gold decoration around Pyotdykes spearhead socket. Photo by Lore Troalen of NMS

 

The Pyotdykes band has a more elaborate scheme featuring filled triangles between zones of up to seven lines. In each case, the design was probably incised into the end of the bronze socket, and then a seamless hoop of thin gold foil was slipped over the end and pressed in, to take the design.

 

 

One of the Pyotdykes swords had been buried in a scabbard made from hazelwood, just as the Carnoustie sword had been. As with the Carnoustie hoard, this proved really useful in providing suitable material for radiocarbon dating. The Pyotdykes hoard is now dated to 900–790 BC, slightly later than the Carnoustie Hoard which was dated to between 1118-924 BC.

The dates are interesting because they suggest that the two hoards were probably not contemporary with each other but may have been separated in time by as much as 300 years. This makes the similarities between the hoards all the more fascinating because while these suggest a similar idea behind why they were buried – perhaps safe-keeping rather than ritual given that the Carnoustie hoard lies within the middle of a settlement unlike most hoards which were deposited in watery places (rivers, bogs, lochs) – it was not one event that spurred this. This cultural custom of burying precious possessions for safe-keeping (for whatever reasons) was probably practised in this region for several centuries in the Late Bronze Age. And for whatever reasons, those who buried the hoards at Carnoustie and Pyotdykes, never returned to reclaim them.

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Carnoustie High School Workshops

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Earlier in June a team of GUARD Archaeologists made a visit to Carnoustie High School, which lies adjacent to the archaeological site. Approximately 22 students had been selected by the school for some archaeological workshops. An initial presentation by the excavation director provided an overview of the project from the initial evaluation, through the excavation, and into the post-excavation process, which is the stage we are at the moment. After the talk, the school students were split into two groups, one for drawing artefacts and one for photography, with each workshop led by GUARD Archaeology’s Graphics Officers.

During the Artefacts Illustration workshop, the students were shown a selection of finds from Carnoustie (prehistoric stone tools, lithics and pottery) and were then asked to select one that they would like to draw. They then learned how to draw different types of artefacts by drawing around it then using dividers to measure and correct the outline. They also used a magnifier to add in detail and were given a small light to create a light source for shading. Once they had finished the pencil drawing they traced over it using fibre tipped pens to produce a final drawing.

For the Artefacts Photography workshop, the students took pictures of prehistoric stone tools and pottery using either a portable light box or portable desk lights. They learned how to use photo scales and also how lighting can emphasise detail of an object. The students were also taught how to use a digital SLR camera to achieve best results for close up images of artefacts under different lighting.

 

These workshops will be followed up with a second day in Autumn 2018 which will examine more of the results from the post-excavation analyses and the science behind each specialism.

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Lithics Analysis

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602 lithic artefacts were recovered from the Carnoustie excavation and subjected to analysis by Torben Ballin. He found out that the lithics mainly comprise flint and quartz but with some pitchstone and quartzite. About 92% of this assemblage is waste material produced in the making of prehistoric stone implements. The remaining 8% of the lithic artefacts are actual tools such as arrowheads, knives and scrapers.

The flint included local material collected along the nearby shores of the North Sea (this kind is quite common in assemblages from eastern Scotland) as well as Yorkshire flint. The local flint/Yorkshire flint ratio is 68:32. In this region of Scotland, the local reddish flint was used throughout prehistory, whereas the Yorkshire flint was used mainly during the Middle and Late Neolithic periods. This is borne out by the two  timber halls at Carnoustie (that are likely to be Early Neolithic) which are entirely devoid of Yorkshire flint, whereas this type of flint is common in the pit groups elsewhere on the site that contained later Neolithic objects.

Five pieces of pitchstone were also recovered. This form of volcanic glass (a close ‘cousin’ of obsidian) was procured from the Isle of Arran in the Firth of Clyde. The distribution of diagnostic pitchstone objects and associated materials like Cumbrian tuff and pottery of the Carinated Bowl Tradition suggests that in southern, central, and eastern Scotland most pitchstone probably dates to the Early Neolithic period.

One of Torben’s conclusions is that though the archaeological features we excavated indicate that the location was occupied during the Early Neolithic (the timber halls), the later Neolithic (the pit groups), and the Bronze Age (the roundhouses and the hoard), the diagnostic lithics only derive from the two earlier periods. The timber halls are associated with Early Neolithic lithics (leaf-shaped points, pitchstone), whereas the pit groups seem to be associated with exclusively later Neolithic lithics (oblique arrow-heads, Yorkshire flint, Levallois-like technique). There appear to be no diagnostic lithic artefacts from the Bronze Age.

 

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Post-excavation examination of the site

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In March 2018, the final programme of post-excavation analyses of the archaeological remains at Carnoustie got underway with the wet-sieving of the soil samples taken during the excavation. This is the process by which we recover tiny minute environmental evidence (such as charred cereal grains) which might reveal the diet of the people who inhabited the site at Carnoustie during the Neolithic and Bronze Age.

And just as the post-excavation analyses of the hoard began with a Post-Excavation Research Design so does this programme of work, laying out the key questions we want answers to and the various types of specialist analysis appropriate to each type of archaeological material that might answer questions like:

  • What period or periods are represented by the artefacts and features?
  • Can datable features reveal further patterns in distribution of activity across the site?
  • Does the artefactual assemblage reflect a typical assemblage, reflective of the periods in question and is contemporary local/regional/national trade represented in the assemblages?
  • Has settlement been continuous or periodic from the Neolithic to Later Bronze Age periods
  • Are there discernible phases in the settlement of this site in the Neolithic and Bronze Age
    periods?
  • How does the Bronze Age weapon deposits relate to the settlement activity and other
    archaeological features, temporally and spatially?
  • How has the local environment changed over the sequence represented by the deposits sampled?
  • What changes over time can be directly related to human intervention and/or natural processes?
  • Is the environmental record reflective of sustained cultivation in this locale during the Neolithic/Bronze Age period? or is there evidence of other land use here?
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Post-excavation analyses of the hoard

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In January 2018, the specialist post-excavation analyses of the Carnoustie hoard was collated into a report by Alison Sheridan. This revealed that the sword had been wrapped in a woolen blanket or cloak when it was buried.  The leaf-shaped bronze sword is classed as a Ewart Park type. Radiocarbon dates for Ewart Park phase metalwork in Scotland are sparse; the Carnoustie date of around 1000 BC is valuable new knowledge, which extends this phase of metalwork backwards in time than the 900–800 BC date bracket usually attributed for Ewart Park metalwork.

The spearhead had been wrapped in sheepskin when it was buried with the sword. The leaf-shaped bronze spearhead is of Type 11A in the latest typology of British Late Bronze Age spearheads and is among the longest examples of its type. There were no traces of wood (from a shaft) in its socket. Compositional analysis of the bronze of the spearhead, undertaken by Peter Northover, revealed that it comprises 86.7% copper, 11.4% tin and 0.68% lead, with trace amounts of several other elements. Lead isotope analysis by Jane Evans and Vanessa Pashley of the Natural Environment Research Council revealed that the lead probably originated in a central English ore field. Compositional analysis of the gold by Lore Troalen from National Museums Scotland revealed the gold to be of high purity, and lead isotope analysis of the gold showed that it grouped with southern Irish and southern British ore compositions. An origin of the lead content in an English ore field seems likely.

The Carnoustie spearhead is one of only five examples of spearheads adorned with gold binding in Britain and Ireland, the others being from Pyotdykes near Dundee, Harrogate in Yorkshire, Lough Gur in County Limerick in south-west Ireland and another from Ireland.

A complete but fragmented bronze sunflower-headed, swan’s neck bronze pin was found lying over the pommel, hilt and upper blade area of the sword, its head at the pommel end. Fragments of woven textile were associated with this pin, including in the narrow area between the shank and the back of the pinhead – thereby indicating that the pin had been used to securing the woolen cloth wrapped around the sword. Compositional analysis using X-ray fluorescence revealed that the pin, like the sword and the spearhead, is of leaded bronze.

The fragments of textile were examined by Susanna Harris of the University of Glasgow using scanning electron microscopy, who concluded that all were of sheep’s wool, and that at least two different textiles were represented. One, found around the socket of the spearhead is a fine, tabby weave, woven using z-spun thread with one thread system finer that the other. The other, found associated with the pin and the annular mount that decorated the scabbard, is a slightly coarser fabric, woven with z-spun yarns with thread systems of similar diameter. There is no sign of any dye in either fabric.

The fact that a very similar deposit was found at Pyotdykes, just 20 km to the west of Carnoustie is remarkable. Along with numerous other finds of Late Bronze Age metalwork in Tayside and Fife, this attests to the wealth of the Late Bronze Age elite in this part of Scotland. The Pyotdykes deposit comprised two swords (with traces of a composite wood and animal skin scabbard associated with one) and a gold-bound spearhead.

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Our first radiocarbon date

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One of the key questions we had was: precisely how old was the Carnoustie hoard? This is where the wooden scabbard (identified by Archaeobotanist Susan Ramsay as made of thin strips of hazel) was important because unlike metal, this could be radiocarbon dated.

In September 2017, we received the radiocarbon date for the wooden scabbard from the Scottish Universities Environmental Research Centre in East Kilbride. The radiocarbon dating revealed a 95.4% that the scabbard dated to between 1118 BC and 924 BC. This is very significant new evidence because it not only dates the burying of the hoard to around 1000 BC but is one of the few direct scientific dates for such Late Bronze Age metalwork in Britain (because most of such metalwork has no organic remains that can be radiocarbon dated).

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Interim Report

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It is important to realise that archaeological excavations are not an end in themselves. Excavations are really just the gathering of archaeological evidence. This evidence needs to be analysed to make sense of what the archaeological remains mean. So the archaeological fieldwork – such as the evaluation which first discovered that there was archaeology here at Carnoustie, the monitored stripping of topsoil which revealed the extent of archaeology and the excavation which recorded the archaeological remains and recovered the archaeological arefacts  – this is just the beginning of a long process of investigation.

Therefore the first thing archaeologists do once they have completed an excavation, is to prepare an interim report. This is called a Data Structure Report and provides the initial results of the fieldwork. The main purpose of this report is to provide a record of the archaeological features that have been excavated, showing where these features are and offering preliminary interpretation. The Carnoustie excavation interim report, which was completed in June 2017, is important for the subsequent specialist analyses of the finds because it shows exactly where each artefact was found and allows us to gradually build up a picture of how and when the various archaeological features were created and abandoned.

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Excavation completed

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On 17 February 2017, the GUARD Archaeology team completed their excavation of the archaeological remains at Balmachie Road, Carnoustie. Altogether they had recorded the remains of up to 12 sub-circular houses that probably date to the Bronze Age along with the remains of two rectilinear halls that likely date to the Neolithic period. The Neolithic features are significant in themselves, and include the largest Neolithic Hall ever found in Scotland. The hoard was buried in a pit close to a roundhouse that cut through the large Neolithic hall.

Over the previous six months, the Carnoustie excavation had received a lot of interest. Not least from teachers and pupils at Carnoustie High School, which lies adjacent to the site. So GUARD Archaeologists had led guided tours of the excavation to 200 pupils and teachers from Carnoustie High School and other schools in Angus. Following requests from Angus Council, GUARD Archaeology were also able to offer week-long work placements to two pupils from Carnoustie High School and Brechin High School Community, who are interested in studying archaeology at University. The Carnoustie excavation ended with Open Days and guided tours of the  site over the last two days of the excavation in February 2017 attended by over 200 people.

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Specialist examination of the hoard

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Normally post-excavation analyses of artefacts recovered from excavations only begins once the entire excavation has been completed. But in the case of the Carnoustie hoard, specialist analyses was required as soon as possible. This was because the organic remains within the hoard were so delicate and fragile that there was a danger that they would degrade within a very short time. They urgently needed conservation but before this could take place, specialists required to examine the remains and take appropriate samples for scientific testing (such as radiocarbon dating, isotope analyses, X-ray Fluorescence analyses) to extract crucial information about the artefacts.

So post-excavation analyses of the hoard begins in January 2017 with a Post-Excavation Research Design that lays out the key questions we want answers to and which identifies the various types of specialist analysis appropriate to each type of archaeological material that might answer these questions.

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