Introduction
We were invited to evaluate the geoarchaeology of a site at Chester Roman Amphitheatre, 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 Triassic Pebble Beds conglomerate, a member of the Sherwood Sandstone group, we found the soils likely to be seasonally waterlogged, slowly permeable, typical stagnogley soils. The site lies on fairly flat ground at the top of the north bank of the River Dee, in an area of land that is now part of the developed city centre, where the amphitheatre has been exposed and conserved for public display.
There was a short visit to the site where deposits were examined and samples were taken for later analysis.
Findings
On examination, some of the layers within the deposits were found to be laminated and sorted, where as others were poorly sorted and appeared slaked and slumped. The evidence pointed towards deposition in water that was standing rather than flowing.
Conclusions
From our investigations, we were able to tell the excavating archaeologists that the deposits were laid down in still water - perhaps in a tank or a pond, the deposits also have quite a coarse texture and some detail may have been lost. It was also felt that due to the effect of the coarse nature of the environment and post-depositional processes, further analysis is unlikely to be worthwhile.