Feeling the Peat: Investigating peat charcoal as an iron smelting fuel for the Scottish Iron Age
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Published
Aug 3, 2025
Abstract
The limited woodland resources that have characterised the Northern Isles of Scotland for millennia pose serious questions when attempting to understand how prehistoric communities fuelled their iron smelting endeavours. The archaeological evidence from the Northern Isles and ethnographic studies from the 19–20th centuries tentatively suggests that peat could have been used for such iron smelting activities. This research considers whether peat charcoal is a viable iron smelting fuel via an experimental campaign. Thermal data produced by this campaign, as well as a metallographic and chemical study of the products from the smelts suggest that charcoaled peat may be capable of producing an iron bloom. Important discussions concerning technical, economic, and ideological aspects of Iron Age metalworking can arise from a recognition of peat in the iron smelting process.
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Keywords
peat, Scotland, Prehistory, experimental archaeology, iron smelting, microscopy, pXRF
References
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Bourgarit, D. (2019). Minerology of slags: a key approach for our understanding of ancient copper smelting processes, EMU Notes in Mineraology 20, 203–231. doi: 10.1180/EMU-notes.20.5
Campbell, E. (1998). Metalworking. In Sharples, N. (Ed.) Scalloway: A Broch, Late Iron Age Settlement and Medieval Cemetery in Shetland (pp. 123–124). Oxford: Oxbow.
Card, N. & Downes, J. (2003). Mine Howe – the significance of space and place in the Iron Age. In Downes, J. & Ritchie, A. (Eds.) Sea Change: Orkney and Northern Europe in the Later Iron Age AD 300–800 (pp. 11–19). Angus: Pinkfoot Press.
Carter, S. P., McCullagh, R. P. J. & MacSween, A. (1995). The Iron Age in Shetland: excavations at five sites threatened by coastal erosion, Proceedings of the Society of Antiquaries Scotland 125, 429–482. doi: 10.9750/PSAS.125.429.482
Curle, A. O. (1936). Account of the excavation of an iron smeltery, and of an associated dwelling and tumuli at wiltrow in the parish of Dunrossness, Shetland, The Society of the Antiquaries of Scotland 70, 153–169. doi: 10.9750/PSAS.070.153.169
Davis, C.A. (1911). The Uses of Peat for Fuel and Other Purposes. Washington: Government Printing Office.
Dickson, C. (1994). Plant remains. In Smith, B. B. (Ed.) Howe: four millennia of Orkney prehistory: 1978-82 (pp. 125–139). Edinburgh: Society of Antiquaries of Scotland.
Edwards, K. J., Whittington, G., Robinson, M. & Richter. D. (2005). Palaeoenvironments, the archaeological record and cereal pollen detection at Clickimin, Shetland, Scotland, Journal of Archaeological Science 32, 1741–1756. doi: 10.1016/j.jas.2005.06.004
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Farrell, M. (2015). Later prehistoric vegetation dynamics and Bronze Age agriculture at Hobbister, Orkney, Scotland, Vegetation History and Archaeobotany 24(4), 467–486. doi: 10.1007/s00334-014-0507-6
Fenton, A. (1978). The Northern Isles: Orkney and Shetland. Edinburgh: John Donald Publishers.
Fenton, A. (1997). The Northern Isles: Orkney and Shetland (2nd edition). East Linton: Tuckwell Press.
Hall, N. S. (2017). An investigation into phosphoric iron production in Eastern England (PhD thesis, University of Nottingham).
Henrich, J. & McElreath, R. (2003). The evolution of cultural evolution, Evolutionary Anthropology 12(3), 123–135.doi: 10.1002/evan.10110
Holden, T. & Boardman, S. (1998). Crops. In Sharples, N. (Ed.) Scalloway: A Broch, Late Iron Age Settlement and Medieval Cemetery in Shetland (pp. 99–106). Oxford: Oxbow.
Jack, P. M. (2023). Peat Burns: The Methods and Implications of Peat Charcoaling, EXARC 2023/1. https://exarc.net/ark:/88735/10677
MacDonald, D. A. (1962). A’ dèanamh gual Gàidhealach nuair a bha gual gann [Making charcoal when coal was scarce]. Retrieved December 09, 2024, from: https://www.tobarandualchais.co.uk/track/37403.
MacLeod, M. & Maclean, J. (1971). Smithy and hen-farm in Jura. Retrieved December 09, 2024, from: https://www.tobarandualchais.co.uk/track/101105.
Mahler, D. L. D. & Jouttijärvi, A. (2005). Experiments with peat charcoal and iron production in the Faeroe Islands. In Mortensen, A. & Arge, S. V. (Eds.) Viking and Norse in the North Atlantic: select papers from the fourtheenth Viking Congress (pp. 92–98). Tórshavn: Foroya.
Manning, W. H. (1972). Ironwork Hoards in Iron Age and Roman Britain, Britannia 3, 224–250. doi: 10.2307/526028
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Oaks, R. (2018). Making Charcoal and Biochar: A Comprehensive Guide. Wiltshire: The Crowdwood Press.
Piggott, S., Burgess, E. M. & Henshall, A. (1955). Three metal-work hoards of the Roman period from southern Scotland, Proceedings of the Society of Antiquaries of Scotland 87(1), 1–50.
doi: 10.9750/PSAS.087.1.50
Pleiner, R. (2000). Iron in Archaeology: The European Bloomery Smelters. Prague: Archeologický ústav AV ČR.
Richards, C. (1996). Monuments as landscape: creating the centre of the world in late Neolithic Orkney, World Archaeology 28(2), 190–208. doi: 10.1080/00438243.1996.9980340
Roux, V. (2010). Technological Innovations and Developmental Trajectories: Social Factors as Evolutionary Forces. In O’Brien, M. J. & Shennan, S. J. (Eds.) Innovation in Cultural Systems: Contributions from Evolutionary Anthropology (pp. 217–235). Cambridge, MA: MIT Press. doi: 10.7551/mitpress/8102.003.0019
Rydin, H. & Jeglum, J. K. (2013). Peat and Organic Soil. In Rydin, H. & Jeglum, J.K. (Eds.) The Biology of Peatlands, (2nd edition, pp. 85–108). Oxford: Oxford University Press. doi: 10.1093/acprof:osobl/9780199602995.003.0005
Schmidt, P. R. & Childs, S. T. (1995). Ancient African iron production, American Scientist 83(6), 524–534.
Schubert, H. R. (1957). History of the British Iron and Steel Industry From c.450 B.C. to A.D. 1775. London: Routledge
Scott, D. A. (1991). Metallography and Microstructure of Ancient and Historic Metals. London: Archetype.
Shirazi, A., Shirazy, A., Saki, S. & Hezarkhani, A. (2018). Geostatistics Studies and Geochemical Modeling Based on Core Data, Sheytoor Iron Deposit, Iran, Journal of Geological Resource and Engineering 6, 124–133.
Small, A. (1964). Excavations at Underhoull, Unst, Shetland, Proceedings of the Society of Antiquaries of Scotland 98(1), 225–248. doi: 10.9750/PSAS.098.225.248
Smith, B. B. (1994a). The Middle Iron Age broch and settlement. In Smith, B. B. (Ed.) Howe: four millennia of Orkney prehistory: 1978-82 (pp. 40–90). Edinburgh: Proceedings of the Antiquaries of Scotland.
Smith, B. B. (1994b). The Environmental Evidence. In Smith, B. B. (Ed.) Howe: four millennia of Orkney prehistory: 1978-82 (pp. 121-124). Edinburgh: Proceedings of the Antiquaries of Scotland.
Timpany, S., Mighal, T., Foster, I., Cortizas, A. M., Owen, O., Krus, A. & Kamerling, I. (2020). Later Prehistoric and Norse Communities in the Northern Isles: multi-proxy environmental investigations on Orkney, Environmental Archaeology 27(2), 146–167. doi: 10.1080/14614103.2020.1803014
Tylecote, R. F. (1990). The Prehistory of Metallurgy in the British Isles. London: Institute of Metals.
Vega, E., Dillmann, P., L’Héritier, M., Fluzin, O., Crew, P. & Benoit, P. (2003). Forging of phosphoric iron. An analytical and experimental approach. In: Associazione Italiana di Metallurgia (Ed.) Archaeometallurgy in Europe: Proceedings of the international conference, 24.-26. September 2003 (pp. 337–346). Milano: Associazione Italiana di Metallurgia.
Zlobinskiy, B. M. (1949). Peat Briquettes as Blast-Furnace Fuel. Retrieved December 12, 2024, from: https://www.cia.gov/readingroom/docs/CIA-RDP80-00809A000600300683-0.pdf
Bayley, J., Crossley, D. & Ponting, M. (2008). Metals and Metalworking: A research framework for archaeometallurgy. London: The Historical Metallurgical Society.
Bourgarit, D. (2019). Minerology of slags: a key approach for our understanding of ancient copper smelting processes, EMU Notes in Mineraology 20, 203–231. doi: 10.1180/EMU-notes.20.5
Campbell, E. (1998). Metalworking. In Sharples, N. (Ed.) Scalloway: A Broch, Late Iron Age Settlement and Medieval Cemetery in Shetland (pp. 123–124). Oxford: Oxbow.
Card, N. & Downes, J. (2003). Mine Howe – the significance of space and place in the Iron Age. In Downes, J. & Ritchie, A. (Eds.) Sea Change: Orkney and Northern Europe in the Later Iron Age AD 300–800 (pp. 11–19). Angus: Pinkfoot Press.
Carter, S. P., McCullagh, R. P. J. & MacSween, A. (1995). The Iron Age in Shetland: excavations at five sites threatened by coastal erosion, Proceedings of the Society of Antiquaries Scotland 125, 429–482. doi: 10.9750/PSAS.125.429.482
Curle, A. O. (1936). Account of the excavation of an iron smeltery, and of an associated dwelling and tumuli at wiltrow in the parish of Dunrossness, Shetland, The Society of the Antiquaries of Scotland 70, 153–169. doi: 10.9750/PSAS.070.153.169
Davis, C.A. (1911). The Uses of Peat for Fuel and Other Purposes. Washington: Government Printing Office.
Dickson, C. (1994). Plant remains. In Smith, B. B. (Ed.) Howe: four millennia of Orkney prehistory: 1978-82 (pp. 125–139). Edinburgh: Society of Antiquaries of Scotland.
Edwards, K. J., Whittington, G., Robinson, M. & Richter. D. (2005). Palaeoenvironments, the archaeological record and cereal pollen detection at Clickimin, Shetland, Scotland, Journal of Archaeological Science 32, 1741–1756. doi: 10.1016/j.jas.2005.06.004
Encyclopaedia Britannica (n.d.a). Sulphur. Retrieved December 12, 2024, from: https://www.britannica.com/science/sulfur
Farrell, M. (2015). Later prehistoric vegetation dynamics and Bronze Age agriculture at Hobbister, Orkney, Scotland, Vegetation History and Archaeobotany 24(4), 467–486. doi: 10.1007/s00334-014-0507-6
Fenton, A. (1978). The Northern Isles: Orkney and Shetland. Edinburgh: John Donald Publishers.
Fenton, A. (1997). The Northern Isles: Orkney and Shetland (2nd edition). East Linton: Tuckwell Press.
Hall, N. S. (2017). An investigation into phosphoric iron production in Eastern England (PhD thesis, University of Nottingham).
Henrich, J. & McElreath, R. (2003). The evolution of cultural evolution, Evolutionary Anthropology 12(3), 123–135.doi: 10.1002/evan.10110
Holden, T. & Boardman, S. (1998). Crops. In Sharples, N. (Ed.) Scalloway: A Broch, Late Iron Age Settlement and Medieval Cemetery in Shetland (pp. 99–106). Oxford: Oxbow.
Jack, P. M. (2023). Peat Burns: The Methods and Implications of Peat Charcoaling, EXARC 2023/1. https://exarc.net/ark:/88735/10677
MacDonald, D. A. (1962). A’ dèanamh gual Gàidhealach nuair a bha gual gann [Making charcoal when coal was scarce]. Retrieved December 09, 2024, from: https://www.tobarandualchais.co.uk/track/37403.
MacLeod, M. & Maclean, J. (1971). Smithy and hen-farm in Jura. Retrieved December 09, 2024, from: https://www.tobarandualchais.co.uk/track/101105.
Mahler, D. L. D. & Jouttijärvi, A. (2005). Experiments with peat charcoal and iron production in the Faeroe Islands. In Mortensen, A. & Arge, S. V. (Eds.) Viking and Norse in the North Atlantic: select papers from the fourtheenth Viking Congress (pp. 92–98). Tórshavn: Foroya.
Manning, W. H. (1972). Ironwork Hoards in Iron Age and Roman Britain, Britannia 3, 224–250. doi: 10.2307/526028
Mathieu, L. (2019). Origin of the Vanadiferous Sperentine-Magnetite Rocks of the Mt. Sorcerer Area, Lac Dore Layered Intrusion, Chibougamau, Quebec, Geosciences 9, 110–146. doi: 10.3390/geosciences9030110
Oaks, R. (2018). Making Charcoal and Biochar: A Comprehensive Guide. Wiltshire: The Crowdwood Press.
Piggott, S., Burgess, E. M. & Henshall, A. (1955). Three metal-work hoards of the Roman period from southern Scotland, Proceedings of the Society of Antiquaries of Scotland 87(1), 1–50.
doi: 10.9750/PSAS.087.1.50
Pleiner, R. (2000). Iron in Archaeology: The European Bloomery Smelters. Prague: Archeologický ústav AV ČR.
Richards, C. (1996). Monuments as landscape: creating the centre of the world in late Neolithic Orkney, World Archaeology 28(2), 190–208. doi: 10.1080/00438243.1996.9980340
Roux, V. (2010). Technological Innovations and Developmental Trajectories: Social Factors as Evolutionary Forces. In O’Brien, M. J. & Shennan, S. J. (Eds.) Innovation in Cultural Systems: Contributions from Evolutionary Anthropology (pp. 217–235). Cambridge, MA: MIT Press. doi: 10.7551/mitpress/8102.003.0019
Rydin, H. & Jeglum, J. K. (2013). Peat and Organic Soil. In Rydin, H. & Jeglum, J.K. (Eds.) The Biology of Peatlands, (2nd edition, pp. 85–108). Oxford: Oxford University Press. doi: 10.1093/acprof:osobl/9780199602995.003.0005
Schmidt, P. R. & Childs, S. T. (1995). Ancient African iron production, American Scientist 83(6), 524–534.
Schubert, H. R. (1957). History of the British Iron and Steel Industry From c.450 B.C. to A.D. 1775. London: Routledge
Scott, D. A. (1991). Metallography and Microstructure of Ancient and Historic Metals. London: Archetype.
Shirazi, A., Shirazy, A., Saki, S. & Hezarkhani, A. (2018). Geostatistics Studies and Geochemical Modeling Based on Core Data, Sheytoor Iron Deposit, Iran, Journal of Geological Resource and Engineering 6, 124–133.
Small, A. (1964). Excavations at Underhoull, Unst, Shetland, Proceedings of the Society of Antiquaries of Scotland 98(1), 225–248. doi: 10.9750/PSAS.098.225.248
Smith, B. B. (1994a). The Middle Iron Age broch and settlement. In Smith, B. B. (Ed.) Howe: four millennia of Orkney prehistory: 1978-82 (pp. 40–90). Edinburgh: Proceedings of the Antiquaries of Scotland.
Smith, B. B. (1994b). The Environmental Evidence. In Smith, B. B. (Ed.) Howe: four millennia of Orkney prehistory: 1978-82 (pp. 121-124). Edinburgh: Proceedings of the Antiquaries of Scotland.
Timpany, S., Mighal, T., Foster, I., Cortizas, A. M., Owen, O., Krus, A. & Kamerling, I. (2020). Later Prehistoric and Norse Communities in the Northern Isles: multi-proxy environmental investigations on Orkney, Environmental Archaeology 27(2), 146–167. doi: 10.1080/14614103.2020.1803014
Tylecote, R. F. (1990). The Prehistory of Metallurgy in the British Isles. London: Institute of Metals.
Vega, E., Dillmann, P., L’Héritier, M., Fluzin, O., Crew, P. & Benoit, P. (2003). Forging of phosphoric iron. An analytical and experimental approach. In: Associazione Italiana di Metallurgia (Ed.) Archaeometallurgy in Europe: Proceedings of the international conference, 24.-26. September 2003 (pp. 337–346). Milano: Associazione Italiana di Metallurgia.
Zlobinskiy, B. M. (1949). Peat Briquettes as Blast-Furnace Fuel. Retrieved December 12, 2024, from: https://www.cia.gov/readingroom/docs/CIA-RDP80-00809A000600300683-0.pdf
How to Cite
Jack, P. M. (2025). Feeling the Peat: Investigating peat charcoal as an iron smelting fuel for the Scottish Iron Age. Historical Metallurgy, 55(2), 98-109. https://doi.org/10.54841/hm.682
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How to Cite
Jack, P. M. (2025). Feeling the Peat: Investigating peat charcoal as an iron smelting fuel for the Scottish Iron Age. Historical Metallurgy, 55(2), 98-109. https://doi.org/10.54841/hm.682