Field visit and fuel burning: the ongoing story of Structure Eight

By Sarah Jane Haston

I am coming to the end of the second year of my masters by research programme (MRes) looking at the charred plant remains from Structure Eight and will soon be taking this project forward through PhD study.

One of the biggest highlights of 2022 was making a field visit to the Ness of Brodgar in August, during the excavations.

It was great to see the site in its landscape setting and hear all the latest ideas of how the different buildings were constructed and their relationships with underlying and neighbouring structures. 

During a tour of the excavation, led by director Nick Card, with my supervision team, we were able to discuss the site in depth, with particular reference to Structure Eight, the focus of my MRes project Farming at the Edge – Neolithic Agricultural Evidence from the Ness of Brodgar, Orkney.

It was really useful to talk about what I have been finding in the samples with Nick and others working on the dig, along with supervisors Scott Timpany and Rosie Bishop. This allowed us to bring our thoughts together on what the plant remains are telling us in terms of agricultural practices, diet, and fuel use.

The benefits of being able to see the site and Structure Eight were enormous in that it has given me a deeper understanding of the site, the scale of the structures and the features from which my samples were taken.

Seeing the deposits being excavated by the team has also helped me to understand the types of deposits recorded for the Structure Eight samples.

Radiocarbon dates from Structure Eight have indicated that it was in use during the first quarter of the third millennium BC with available dates showing it was active from 3005-2915 cal BC (UBA-26535; 4380±35 BP) to 2990-2910 cal BC (SUERC-60417; 4350±35 BP) – broadly contemporary with the primary phases of Structures One, Twelve and Fourteen and later Structure Ten during Eight’s secondary phase (Card et al. 2018).

To the south-east of Trench P, the excavation carried out in Trench T, showed a section through the midden mound.  

The distinct layers of deposits of orange peat ash and dark brown charcoal rich deposits were numerous.

This is similar to the midden deposits that were found in the Central Midden Area of Trench P, found between Structures One, Eight and Twelve. 

The scale of the midden deposits in Trench P is remarkable and gives some indication of how much waste material was being produced at the Ness.

Large volumes of ash are produced when peat and turf are burnt as a fuel (Church et al. 2005, 2007, Church and Peters 2004; Simpson et al. 2003, Simpson et al. 2006) and the charcoal and charred plant remains left following this burning can be used as a way of identifying this practice on site, together with other methods, such as soil micromorphological analysis.

Assessment complete

I have now completed the assessment of samples taken during the excavation of Structure Eight, with 519 samples, representing 194 soil contexts, assessed for charred plant remains.

Of the samples assessed, 495 produced charred plant remains and/or wood charcoal remains, with 181 of the samples found to contain charred cereal grains.

Much of the archaeobotanical assemblage from the Structure Eight samples indicates the use of heath grass and turf as a fuel source.  Charred seeds and flowers of ling heather (Calluna vulgaris L. Hull) and cross-leaved heath (Erica tetralix) are recovered along with other shrubby heathland plants of crowberry (Empetrum nigrum L.) and cowberry (Vaccinnium vitis-idaea L.).

The frequent seeds and stems of grasses (Poaceaea sp.), most notably heath grass (Danthonia decumbens L.), nutlets of different sedges (Carex spp.) and herbs such as tormentil (Potentilla erecta) and St. John’s Wort (Hypericum perforatum also point to the collection and use of the acidic moorland vegetation.  

Similar charred assemblages indicating the use of turf for fuel are seen at other Neolithic sites in Orkney, such as Skara Brae (Dickson & Dickson, 2000), Catasand (Timpany pers comm.), Pool, Toftsness (Dockrill et al., 1994)  and this use of turf as fuel continued to the later prehistoric periods such as at the Early to Late Iron Age site at Howe (Dickson, 1994) and to historic periods in the Northern Isles, when woodland resources were likely more limited than in prehistory.

The charcoal fragments are mostly of small, shrubby twigs and stems of heather and other woody shrubs, which again may be derived from the burning of turves as fuel.

Previous charcoal identifications from the structure (Montano and Timpany, 2017) have shown wood fuel to be dominated by birch (Betula sp.), a tree which also grows in heathland and thus may represent older wood within the peat/turf being used for fuel as much as being burnt in its own right.

The burning of driftwood has also been identified with spruce (Picea abies) and larch (Larix sp.) present in the assemblage, together with potentially more local tree types in the form of hazel (Corylus avellana), oak (Quercus sp.) and willow (Salix sp).

Future work is planned to develop this initial research into fuelwoods from Structure Eight to see if other taxa can be identified and to tie the Ness charcoal data to the pollen evidence for this area to determine whether native woodfuel was procured from local sources and how this was resourced (e.g. felling or possible coppicing).

My thanks must go to the Ness Brodgar Trust which has funded this research and allowed me to engage with material from such an exciting site.

The Ness of Brodgar Trust, in turn, wishes to thank the various benefactors for their donations which have made Sarah Jane’s MRes research possible. 

References

• Church, M.J and Peters, C. 2004. Application of mineral magnetism in Atlantic Scotland, Archaeology 2: Archaeobotanical taphonomy in Atlantic Scotland. In Housley, R. & Coles, G.M. (eds) Atlantic connections and adaptations: economies, environments and subsistence in lands bordering the North Atlantic. Oxford: Oxbow, 99-115.
• Church, M. J., Peters, C. P. and Batt, C. M. 2007. Sourcing fire ash on archaeological sites in the Western and Northern Isles of Scotland, using mineral magnetism. Geoarchaeology 22:747-74.
• Church, M. J., Arge, S. V., Brewington, S., McGovern, T. H., Woollett, J. M., Perdikaris, S., Lawson, I. T., Cook, G. T., Amundsen, C., Harrison, R., Yekaterina, K. and Dunbar, E. 2005. Puffins, pigs, cod and barley: Palaeoeconomy at Undir Junkarinsflotti, Sandoy, Faroe Islands. Environmental Archaeology 10:179-197.
• Dickson, C 1994. Plant remains. In Ballin Smith, B (ed) Howe – four millennia of Orkney prehistory excavations 1978-1982. Society of Antiquaries of Scotland Monograph No 9
• Dickson, C and Dickson, J.H. 2000. Plants & People in Ancient Scotland. Tempus.
• Simpson, I. A., Vésteinsson, O., Adderley, W. P. and McGovern, T. H. 2003. Fuel resource utilization in landscapes of settlement. Journal of Archaeological Science 30:1401-1420.
• Simpson, I.A., Guttman, E.B., Cluett, J. and Shepherd, A. 2006. Characterizing Anthropic Sediments in North European Neolithic Settlements: An Assessment from Skara Brae. Geoarchaeology: An International Journal, 21, 221–235
• Montaño, J.M and Timpany, S. 2017. Anthracological study of the Ness of Brodgar: 2013, 2014 and 2015. Orkney Research Centre for Archaeology. UHI Archaeology Institute.