A Day in the Life of the Palaeoenvironmental Lab: Dr Charlotte O'Brien, Environmental Laboratories Manager
I’m Charlotte OBrien, and I manage the Palaeoenvironmental Section of Archaeological Services, the commercial unit within the Archaeology Department. I’m based in the Palaeoenvironmental Lab on the ground floor, along with two other members of the team, Lorne Elliott and Carrie Armstrong.
The lab is always a hub of activity where both commercial and research projects are undertaken. At one end of the lab is the wet processing area, which has several large sinks for washing finds and soil samples. Today, one of our assistant project archaeologists, Rebecca Hercock, is processing soil from a developer-funded excavation near Bailiffgate in Alnwick. She washes the soil samples over a fine sieve before placing them in the drying ovens. Tomorrow, when dry, they will be carefully sorted for seeds and charcoal, and any additional finds, particularly smaller remains such as fish and bird bones, flint, beads and metal-working residues.
The projects room adjoining this lab is where we do the specialised microscope work. It houses several reference collections, including seeds, charcoal and snails, which we use for detailed identifications and in turn, help us provide information about past landscapes and how people interacted with their environment. Between us, Lorne, Carrie and I have over 35 years of experience in this line of work, covering a full range of archaeological sites from across the UK and beyond.
Today, I’m looking at charcoal fragments from a Roman settlement at Hurworth near Darlington, which was excavated in advance of a housing development. Under the high-powered microscope, it is possible to see that different woods have their own individual patterns of vessel arrangements, which allows me to identify them to species. The charcoal from this site comes from ditches, pits, a corn-drying kiln and cremation burials, so the analysis should show which types of wood were used for structural purposes compared to those used as fuelwoods for cremations or drying crops prior to storage and milling.
Next to me, Lorne is working on samples from a medieval site on South Bailey, in the heart of Durham City, and in particular, he is looking at tiny charred and mineral-replaced plant remains. Interestingly, amongst the nutshell, fruitstone and cereal remains, he is finding small fragments of seaweed. In the past, seaweed had a range of uses including food, fodder, preservative and as a fertiliser. One idea we have now is that these are remains of pig manure, but further research is needed.
Carrie is looking at samples taken from a dig at Upper Mountjoy, located on the site of Durham University’s new Mathematical Sciences and Computer Science building. Although the focus is on a series of enclosures dating to the Iron Age and Roman periods, some of the artefacts indicate there was occupation over 1000 years earlier, during the Bronze Age. Carrie is picking out suitable nutshells, seeds and charcoal for radiocarbon dating, so that we can establish a firm timescale for the site. She will be posting these to the radiocarbon lab in Glasgow and we should have the results in 10 weeks’ time.