Coarse Sieving

Coarse Sieving

Samples are taken to reconstruct the ecological, environmental, economic, and social stories of the site/excavation. Archaeological sites can be simple or complex- in terms of features, chronology, the chemical and physical properties of the deposits, and the site formation process. These factors will influence the preservation or loss of different materials. In determining the most appropriate sampling strategies for a site, the excavator should:

  • have clear research goals
  • use all available current knowledge to inform decisions
  • be clear about what features are to be sampled-many types of environmental samples are not clear to the naked eye
  • collect samples from all deposit types not just “good” ones.

Some environmental remains are not homogenously distributed through a deposit, in these cases several samples from the same deposit may be taken. We have several different types of materials that are commonly sampled at the Black Friary. These include faunal bone (butchered and not butchered), and soil samples taken for retrieval of various ecofacts such as insects, plant macro, wood/charcoal, pollen/spores, cremated bone, metallurgy waste, and molluscs. The collection of sample types should be seen as a ‘bulk’ collection- be that a 1 liter bag or 60 liters. When sampling, say for charcoal or molluscs, for example, individual pieces are never handpicked from the matrix. Handpicked samples are biased and may contribute little to the ecological or environmental information you are pursuing.

Animal Bone

Animal Bone

Where a fill is deemed worthy of assessment and is less than 30 liters in volume, then 100% is sampled. Students use black marker to write on the sample bags/buckets. Every sample is given a sample number and registered in the sample register. When labelling samples, we use a lozenge shape symbol to contain the given sample number. The purpose of this is simply for ease of recognizing the sample number amongst the other information provided on the bag or bucket.

When processing soil samples we consider the intended analyses for the sample, as this will determine the type of onsite processing that ensues. As well as processing for ecofacts as outlined above, soil can be collected for a suite of analysis such as particle size analysis, pH analysis, or to conduct analysis on chemical composition. Two processes that are generally employed on site are wet sieving and coarse sieving. When wet sieving the samples is poured directly on the sieves of desired size and a water hose is used to wash it down. The residue in the sieve is then scanned for archaeological material. To coarse sieve the samples is poured directly on the sieve of desired size and a student would use his or her hands or trowel to encourage the soil through the mesh. The sieve is under constant observation for archaeological material.

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