Where are microfossils found?
This table summarizes some of the contexts where our lab and others have recovered terrestrial and freshwater microfossils. Working with these data require an understanding of the following assumptions.
This table summarizes some of the contexts where our lab and others have recovered terrestrial and freshwater microfossils. Working with these data require an understanding of the following assumptions.
- Recovery is often dependent on preservation, and preservation can change over time. Thus, the absence of a microfossil may not be indicative of the absence of that organism on the landscape or artifact. One of the challenges of this kind of research is determining whether you have a biased or unbiased record.
Because microfossil composition varies, conditions ideal for fossil preservation also vary. It is often the case that sediments with good pollen preservation exhibit poor phytolith preservation, and vice versa. Calcium oxalates and fecal spherulites easily dissolve in rain water, but they can be protected from dissolution when encased in organic tissues. Starch granules can mineralize or be protected from microbial decay by binding to charged clay particles. Phytoliths can withstand oxidative conditions, but dissolve over time when exposed to alkaline (high pH) lake water or soil pore water. Pollen can survive acidic, neutral, and alkaline conditions, but does not preserve well under oxidative conditions.