This post is prompted by a first visit to Wessex Archaeology at their Salisbury premises.
The A556 Knutsford to Bowden Improvement scheme (begun in 2014 and due to complete in the winter of 2016-17) involves creating 7.5 km of new dual carriageway.
As part of an assessment of the environmental impact to our cultural heritage (the prehistoric and roman remains), Wessex Archaeology was asked to make the necessary investigations. The material I had from the tank was from bulk samples from Knutsford. This material is stored in tubs (see photo) the samples can vary from a few litres to (usually) up to 40 litres in size. There is a large amount of waste material!
The sample of Knutsford residue I was given to take away is fine pigmented residue left in the base of the flotation tank after the coarse materials and organic matter/ charred matter- molluscs etc have settled or floated off.
The bulk samples collected by all the regional offices are processed in Salisbury.
This will of course be a vertical sample. Not the usual horizontal one I usually access. The material will have been systematically analysed and dated. Site specificity is important to me. The data available takes this to a new level. Monoliths can come from a variety of features, such as ditches and palaeochannels not necessarily just trial trenching and are a way of being able to look closely at the depositional processes going on in that feature. Environmental Archaeologists can also subsample these to look for material such as pollen and organic material for C14 dating as well as foraminifera and ostracods (microscopic organisms that are indicators of water salinity and habitats). The samples from monoliths are generally fairly small, are processed in sieves in the sink and produce little waste material. There are often monoliths surplus to requirement however...again a useful source?
Possible lines of enquiry prompted by the visit:
1. The pigmented residue (that may well interest me in my own work) is a natural waste product that builds up in the base of the cylinders and is empted out into an underground disposal tank. The dark colour of this particular sample is due to charred particles within it. There is a large amount of waste material generated on the site.
3. Nicki Mulhall (Environmental Archaeologist) determines the texture of soils and sediments by finger testing and sight.
I get to know my materials through touch and sight too- but the information I glean is related to the way I might engage with it directly (I need to understand it so that I might use it to form a pigment/ communicate an approximation of its colour or surface quality through a paint medium).
I do not analyse or classify it (so that it may provide information that can contribute to an investigation of place) or situate it clearly within a recognised set of standards. The well-fingered Soil Survey Field Handbook and Soil Colour Charts provide guidance on sampling. Nicki provides information (sediment description and interpretation) to the archaeologists (sometimes before they arrive on site) using very specific language. See 4. below.
Compression Gap; Bands of 10YR 2/2 very dark brown-2/1 black humic detritus, 10yr 4/3 brown medium sand, 10YR 4/2 dark greyish brown tufaceous sand with abundant mollusc shell. Mollusc shells include aquatic and terrestrial species.
Interpretation: Banded alluvial sediments, alternating slow and fast moving water events with a significant period of permanently flowing water.
KNUTSFORD RESIDUE: my own samples.
Samples using PVA medium as a binder, varying quantites of water, and 2 paper surface qualities.
I will try different binders (oil, egg yoke, gum arabic, rabbit skin size).