Iron Age occupation of a large number of sites in the Mun River Valley, northeast Thailand are characterised by distinctive encircling earthworks, these sites being commonly known as “moated sites”. The previous focus on the “moat” as an essential structure has tended to obscure the relationship between site and landscape. This paper reports the preliminary results of the first excavation of any significance within the moats themselves at six sites – Noen U-Loke, Non Muang Khao, Ban Non Khrua Chut, Ban Non Ngiu, Ban Makham Thae and Ban Non Wat – where the structure of the moats has been examined in section. Lithology, stratigraphy and cross-sectional morphology have been recorded and from these observations several broad conclusions may be reached and are reported here. Typically, subsurface features comprise infilled river channels and an undulating bedrock and alluvial surface. Significantly, the surficial morphology of the moats, and notable the regularity of shape and patterning of the moats in plan, usually does not reflect buried channel morphology. The surficial patterning of the moats may, indeed, be a relatively recent phenomenon, and the buried channel features probably reflect more accurately the landscape of the period of Iron Age occupation of the region.
Boyd, WE, McGrath, RJ & Higham, CFW 1999, 'The geoarchaeology of the prehistoric ditched sites of the Upper Mae Nam Mun Valley, Thailand, II: stratigraphy and morphological sections of the encircling earthworks', Indo-Pacific Prehistory Association Bulletin, vol. 18, pp. 169-179.