Archaeologists and mud tend to go hand in hand!
If we’re up to our knees in a particularly rich pit fill, then – more likely than not – there’ll be someone else up to their elbows in the same stuff later at the warehouse, during the post-excavation stages.
While in itself it might not seem very interesting, it can help tell us more about a site.
‘Soils’ are bodies of sediment that have been altered by surface processes such as natural weathering, and bioturbation – root action by plants and the disturbance and/or digestion of soil by animals such as rabbits and earthworms.
‘Buried soils’ are generally found beneath earthworks or under rapidly accumulating sediments such as alluvium, where they represent former ground surfaces. They can provide information about the past environment and land use, and they can help us understand overlying remains; for example, was the area under a barrow deturfed before its construction?
The pH of soil varies across the country, or sometimes even just across the site! The pH of a deposit will have an effect on the different types of materials likely to be preserved. Therefore, a change in pH will have an impact on the chances of survival for any artefacts or organic materials. Very acidic soil will eat away at organic finds, such as plant-based fibres and bone, and make them degrade and become brittle; whereas an extremely low alkali soil would make bone lose its rigidity and degrade to become more bendy.
Soil can provide a wealth of information about the feature that was being excavated and so it is important for archaeologists to collect and analyse soil samples of buried deposits and horizons with any archaeological potential.