An alternative to exotic spore or pollen addition in quantitative microfossil studies

Uncertainties in availability and formulation of exotic microfossils (e.g., Lycopodium spp., Eucalyptus spp.) to be added to microfossil preparations may be resolved by the use of plastic microspheres (25.0 ± 1.0 μm), which are unaffected by standard pollen preparative treatments (KOH, HCl, HF, acetolysis, and organic solvents). The microspheres are sensitive to strongly oxidizing treatments (e.g., Schulze's reagent, H 2 O 2 : H 2 SO 4 reflux for diatom preparation) but can be added following digestion of organic material.Preparation of microsphere suspensions in a suitable electrolyte (e.g., NaCl – formic acid – water) permits calibration by Coulter counter of suitable dilutions (e.g., 5000 ± 100 mL −1 ) for delivery by "Tipet" volumetric flasks.The uniformity and distinctive appearance of the microspheres not only facilitate recognition but also provide a constant reference for both size (25 μm) and volume 8180 μm 3 ), as well as a reference standard for computerized microfossil scanning.The microspheres are inert (vinyl-coated styrene polymer), featureless, opaque, available in a variety of sizes, and of a density (SG = 1.3) similar to those of pollen grains.A stainless steel volumetric sediment sampler (0.5–5.0 cm 3 ) that facilitates subsampling in core or bulk samples is described.