Layers, kilns and buried walls - GPR vs stratigraphy

Clay built walls within a sand/silt fluvial deposit can present through the data in different degrees of clarity. However, a recent survey adjacent to an open archaeological trench has provided a unique chance to test the GPR against known stratigraphy and archaeology.

The trench is part of an ongoing archaeological investigation into a site which was used for waterfront industry since potentially the Iron Age. Artefactual evidence ranges from pottery to clay walled buildings.

The local geology is very much comprised of silts built up through fluvial deposition, possibly identifying as a sand bar promontory.

This trench provides an interesting break from previous construction techniques as it has provided evidence for burnt masonry. This could suggest a kiln or oven nearby and the GPR was used to determine whether the adjacent area could reveal anything of interest relevant to the masonry.

The images above show an Iso projection through GPR-Slice software of high reflective properties within the area. (For reference, the trench lay directly next to this survey area on the right of the grid).

It is clear that a semi-circular structure is present with other areas of interest nearby. The GPR data suggests that within the semi-circular feature is a smaller circular feature with a projection off it. This could be an oven or kiln set within this circular feature.

The beauty of clay within sandy/silt is that it provides high contrast features, especially where a built-up deposit of material overlies the previous ground surface. The GPR was capable of distinguishing land formation stratigraphy within the radargram view of the data (see below).