Examining Medieval Long-Wall frontier systems (11th – 12th centuries AD) through archaeological geophysics in the Eastern Mongolian Steppe Region

• Geophysical survey of a Medieval wall system in northeastern Mongolia. • Exploring the structure and function of 11th century CE walled enclosures. • Integrating gradiometry and GPR in archaeological exploration. • Exposing the wooden poles construction of a Medieval gate structure. This paper presents the results of exploratory geophysical surveys and ground truthing of a cluster of earthen enclosures associated with a long-wall frontier system in northeastern Mongolia. This system dates to the 11th to early 12th centuries AD and was constructed by the Kitan/Liao Dynasty. Square and circular enclosures identified along the south side of the wall system were examined using single axis fluxgate gradiometry and ground penetrating radar. Geophysical prospection assisted in the identification of entry gates, rammed earth wall construction techniques, and interior features within the earthen complexes and assisted with the placement of ground truthing trenches. This approach ensured that geophysical survey was integrated closely with on-going development of the research design for the site and aided the identification and interpretation of construction characteristics associated with the long-wall system and the functions of the enclosures.