Improving archaeological site analysis: a rampart in the middle Orkhon Valley investigated with combined geoscience techniques

The Orkhon Valley in Central Mongolia has joined the World Heritage list in 2004. It hosts multiple archaeological sites from Palaeolithic to Recent which allow reconstructing the settlement history in this part of the Steppe landscape. In the BMBF project ”Geo-Archaeology in the Steppe - Reconstruction of Cultural Landscapes in the Orkhon valley, Central Mongolia” we seek to enhance the knowledge about ancient cultures like the Uighur, Turks and Mongols and their geographic footprint in the centre of Mongolia. Almost one hundred archaeological sites from prehistoric and historic times including ramparts and khirigsuurs were investigated in five field campaigns from 2008 - 2010 in the middle Orkhon Valley. Rampart MOR-2 (Dörvölzhin) proved difficult to date due to the lack of sufficient archaeological surface finds; and its role within a manifold of walled enclosures from different times in the study area remained unclear. A first insight into topographical setting and morphometry of the rampart was gathered by an octocopter equipped with a high resolution range finder camera, which could achieve a spatial resolution in the order of 2.5cm for a DEM. Ground penetrating radar, SQUID magnetometry, and electric resistivity measurements (capacitive coupled geoelectrics) were thereafter used to characterize the sediment distribution of the inner part of the enclosure and the ramparts themselves.