Phytolith Analysis
Phytoliths are naturally occurring siliceous bodies produced by many living plants and may be preserved in the soils or tools of archaeological sites. Phytoliths are created when living plants absorb silica from surrounding groundwater and the silica hardens in place within and between the plants’ cell walls. Depending on the silica’s deposition within the plant, phytolith shapes (morphologies) may indicate the type of plant and plant part being examined. The most durable of archaeological plant remains, phytoliths can provide novel views of past plant communities or human behaviours. Plant families have high, moderate, low, or no phytolith production and a select few families produce diagnostic phytolith morphologies. These characteristics and the frequency in which they occur in soils can provide additional information regarding specific archaeological contexts.
Phytoliths are extracted from soils or tools, examined via light microscopy, quantified by calculating the number of phytoliths per gram of sediment, and characterized to broad plant groups or types. Depending on the provenance of the samples and research questions being asked, we are happy to work with clients to determine appropriate levels of specificity to satisfy their needs and requirements.
Methods:
We currently utilize three types of sediment processing which are modified and/or combined to best suit the sediments of each project or site within a project.
Rapid Sediment Processing is ideal for sediments from well preserved contexts/sediments. Sediments undergo the least amount of treatment, reducing the chance of altering the assemblage and enabling processing in the fastest time possible. This protocol is best suited for well-preserved sediments but can produce slides that are incredibly “full” of clays and sediments, depending on the nature of the sediment.
Acid Insoluble Fraction Analysis enables one to calculate phytolith concentrations regardless of the taphonomic conditions of sediments, allowing intra- and inter-site comparisons. Including AIF concentrations complies with best practices and enables a standard reference unit for quantification of phytoliths for other phytolith practitioners in the field.
Heavy Sonication Processing is an intense processing protocol for clay and/or organic rich sediments. This protocol uses heavy sonication and a deflocculating agent to disarticulate clays from sediment particles, while removing carbonates and organics. This method is time and energy intensive but can increase the purity of extracted phytoliths.
Pricing:
| Sample Processing | Cost Per Sample (CAD) |
| Processing (Variations of rapid, acid insoluble fraction, &/or heavy sonication methods) | $320 |
| Phytolith Concentrations & Morphological Identifications | $250 |
| Analysis and Reporting | Costs Per Project (CAD) |
| Report Writing | $1000 (20 hours) – $2000 (40 hours) |
| Lab Supplies | $50 (1-20 samples) $100 (21-50 samples*) |
| Return Shipping (if desired) | TBD |
*Custom pricing may be necessary for projects over 50 samples.
