Preservation and Sample Processing
Preservation
Although palynology deals with the fossil remains of a wide variety of
fossil organisms (plants, animals, and protists), the uniting feature
of the field is the composition of the fossils -- they are invariably organic
(i.e. carbon-based).
A variety of specific organic compositions are present, but all share
common features:
- C-H-O compounds
- resistant to hydrocholoric (HCl) and hydrofluoric (HF) acids
- complex polymers
- prone to corrosion only in strongly oxidizing environments (e.g., nitric acid and H2O2) or highly alkali (e.g., KOH)
- thermally alter to darker colours by loss of O and H.
The most common material is sporopollenin, best known in the cell walls of
terrestrial plant pollen and spores, but also present in dinoflagellates,
acritarchs and other types of single-celled "algae". The exact structure
of sporopollenin is still uncertain, but according to some authors, it may
be a beta-caratenoid, xanthophyll and fatty-acid polymer. Other types of
chiton-like material are present in scolecodonts, fungal spores, organic
walls of foraminifera, and chitinozoans.
The highly resistent composition of palynomorphs is what allows them to be
preserved in most sedimentary environments, and what enables their
extraction from most lithologies using chemical techinques which would
obliterate most other fossils.
Processing
IMPORTANT NOTE: Palynological processing often involves corrosive,
poisonous, and just plain dangerous chemicals. DO NOT try this yourself
without a completely-equipped lab with fume hood and protective gear, and
direct supervision by someone who has already performed the techniques.
The information presented here is highly summarized, and should not
be considered complete or safe as presented.
The exact technique used for palynological sample processing varies depending
upon the nature of the sample, but all involve the separation and
concentration of organic material, often from rock or sediment dominated
by minerals.
Unconsolidated sediment
Siliclastic and carbonate rocks
Organic-rich rocks (e.g., coal)
References
Barss, M.S. and Williams, G.L., 1973. Palynology and nannofossil processing
techniques. Geological Survey of Canada Paper 73-26, p.1-25.
Authorship
Andrew MacRae, email: