Introduction
We were invited to evaluate the geoarchaeology of a site at St Mellons, Cardiff, and provide a 3-dimensional picture of the deposits and identify former land surfaces, to help the client both in understanding the origins of the deposits and in assessing the archaeological potential of the site.
Background
The bedrock on the site was known to be Mercia Mudstone overlain by alluvial silts, clays and peats of the Wentlooge formation, we found the soils to be pelo-calcareous alluvial gleys which form on marine alluvium. The site lies in a low-lying area between the Rivers Rumney and Usk and groundwater is controlled by ditches and pumps.
Information was gathered by use of data from coring, Electro Resistance Tomography and EM31 survey.
Findings
In general the bedrock was found to be shallow to the north of the Pil-du Reen, and deepened to the south of it to a maximum depth of around 8 metres below the current ground level. Peat was found only over more deeply buried rock in the south and west of the site.
Conclusions
From our investigations, we found that their had been long-term persistent drainage on the site, the course of which is followed in part by the route of the Pil-du Reen today, there was no direct evidence of soil development, and no direct evidence of archaeological artefacts or structures were observed.
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