IDENTIFYING BURNED MUD BRICK BUILDINGS USING FLUXGATE MAGNETOMETRY

• M. Boyd (Fitch Laboratory, British School at Athens, Souidias 52, 106 76 Athens, Greece)
• N. Brodie (McDonald Institute, University of Cambridge, Downing Str., Cambridge, CB2 3ER, UK)

Geophysical techniques of archaeological investigation are well-established, but the interpretation of anomalies is hampered by the lack of excavated examples. This paper describes magnetic anomalies on two prehistoric sites that might be due to burnt clay surviving from mudbrick or wattle-and-daub architecture.

Whereas the ephemeral nature of many prehistoric sites has made their detection through geophysical techniques somewhat difficult, in theory baked clay surviving from a burned mud-brick structure should carry a thermoremanent magnetisation which will be detectable with magnetic techniques. Clay was a common construction material through all periods of Aegean prehistory, and numerous published accounts of buildings destroyed by fire suggest that burnt destruction deposits should be a relatively frequent occurrence in the archaeological record. Thus it is to be expected that burnt structures should be discovered routinely during magnetic surveys, but because of differential patterns of building destruction and collapse their recognition might not be immediate or straightforward.

This is a preliminary investigation of the magnetic characteristics of burnt clay architecture. Large and unusual magnetic anomalies discovered by fluxgate gradiometer surveys at the known prehistoric sites of Koufovouno in Lakonia (neolithic to early bronze age) and Iklena in Messinia (late bronze age) are presented, and evidence derived from excavation and surface survey which supports their interpretation as burned mud-brick or wattle-and-daub features is described and discussed.