Studies of earth-based building materials using geoarchaeological techniques
Earth-based building materials have been studied at the Institute of Archaeology, UCL through geoarchaeological techniques for over 25 years. The main techniques employed are soil micromorphology (Courty et al., 1989), with complementary studies of grain size, chemistry, magnetic susceptibility and microprobe. The types of materials studied included mud brick, turf, daub (also cob, clunch), and building ‘clays’ such as brickearth – in London a natural fine sandy silt loam – found across northern Europe. Experiments on earth (beaten) floor formation (Butser Ancient Farm, UK) and turf roofs (Umeå university, Sweden) have been reported (Cruise and Macphail, 2000; Macphail et al., 2004). Equally, experimental turf mounds have been studied, e.g., the Wareham Experimental Earthwork (Macphail et al., 2003).
Of particular interest in London are the floors constructed of local brickearth, and these are found in Roman and medieval London. Figure 1 and Figure 2 illustrate the kind of information that can be gained through microstratigraphic studies, which go towards understanding the origins of building materials and use of structures. Quarried brickearth was laid down but soon covered with layers of trample, most coming from hearth and food debris. The brickearth itself also became contaminated with phosphate and was affected by burning. This microstratigraphic data is consistent with there being a roofed structure, with other archaeological information suggesting it was an early medieval cook shop in an area that became the London Guildhall. The underlying archaeology includes the Roman London Amphitheatre, which was also very much a brickearth construction (Bateman, 2000; Macphail et al., Submitted 2003).
Bateman, N., 2000. Gladiators at the Guildhall. Museum of London Archaeology Service, London.
Courty, M.A., Goldberg, P. and Macphail, R.I., 1989. Soils and Micromorphology in Archaeology. Cambridge Manuals in Archaeology. Cambridge University Press, Cambridge.
Cruise, G.M. and Macphail, R.I., 2000. Microstratigraphical Signatures of Experimental Rural Occupation Deposits and Archaeological Sites. In: S. Roskams (Editor), Interpreting Stratigraphy. University o f York, York, pp. 183-191.
Macphail, R.I., Crowther, J., Acott, T.G., Bell, M.G. and Cruise, G.M., 2003. The Experimental Earthwork at Wareham, Dorset after 33 years: changes to the buried LFH and Ah horizon. Journal of Archaeological Science, 30: 77-93.
Macphail, R.I., Crowther, J. and Cruise, G.M., Submitted 2003. Microstratigraphy: soil micromorphology, chemistry and pollen, The Guildhall of London: from an 11th-century settlement to a civic and commercial capital. Museum of London Archaeological Service, London.
Macphail, R.I., Cruise, G.M., Allen, M.J., Linderholm, J. and Reynolds, P., 2004. Archaeological soil and pollen analysis of experimental floor deposits; with special reference to Butser Ancient Farm, Hampshire, UK. Journal of Archaeological Science, 31: 175-191.
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