The study of pollen preserved within sedimentary archives can provide a wealth of information relating to the landscapes that have prevailed in the past
Put simply, pollen accumulates within sedimentary layers over time, and reflects the vegetation that existed at that location, at the time of deposition. Over time, vegetation can change in response to natural (climatic) processes and/or associated human activities.
If multiple samples can be analysed through a sedimentary sequence, this provides the opportunity to assess such landscape change. When put into an archaeological context, it is possible to reconstruct the impact of human activities at a site, whether that be through deforestation, agriculture and associated landscape modification.
PERCS can provide guidance with regards suitable sampling strategies depending on the types of deposits under investigation. This in itself can maximise the palaeoenvironmental and geoarchaeological potential of a site through avoiding the evaluation of deposits likely to be of limited palynological value.
PERCS provides a two stage process when undertaking pollen investigations
Pollen assessment is essentially an ‘assessment of potential’, whereby an initial evaluation of the samples is undertaken. If present, key taxa are identified (trees, shrubs, herbs, spores and aquatics), and their relative abundance is noted. Provisional interpretations can be achieved at assessment stage and, if preservation is good enough and the deposits are of significance to the client (in terms of age and/or associated archaeological relevance) recommendations can be made to take the samples and associated sequence to full analysis
Pollen full analysis involves a much greater study of the floral assemblage previously identified. The pollen count is increased in order to maximise the assemblage preserved and to record rare types perhaps not initially encountered at assessment stage. The preservation of the grains is also evaluated (crumpling, corrosion etc), to help understand whether taphonomy (erosion, transportation, deposition) has influenced the assemblage under investigation. Any other evidence present in the samples is also noted (charcoal, non-pollen palynomorphs, other microfossils etc) in order to maximise the interpretative potential of the samples