Introduction
We were invited to evaluate the geoarchaeology of a site at Dial Street, Warrington, to help the excavating archaeologists, both in understanding the origins of the deposits and in assessing the archaeological potential of the site.
Background
The bedrock of the area was known to be Permian and Triassic Sandstones, and we found the soils to be typical sandy gley soils, which are ground water gley soils that have developed on fluvioglacial deposits. The site lies in an area of flat land on a terrace on the edge of the floodplain of the River Mersey. At the time of the excavation the site was situated within an urbanised area of Warrington.
We examined samples in the form of two monoliths supplied by the excavating archaeologists.
Findings
We found the samples to represent both natural and archaeological deposits. In one of the samples we noted that the depth of sediments was in part due to deposition in still or slowly flowing water, there were fine laminations, but not the type of bedding associated with moving water with a significant flow. In the other sample the deposits resembled dumped material, but there was no soil profile.
Conclusions
From our investigations, we were able to tell the excavating archaeologists that these deposits were reworked earlier deposits laid down in still or slow-moving water, and dumped material. Further deposition of material and then construction on top of that had effectively sealed the deposits, preventing soil formation from further mixing them and preserving some of the fine detail. We were able to suggest that phosphate analysis and thin section analysis may provide further information about the materials and the environment in which they had been deposited.