Foraminifera - Uses of Forams

Uses of Forams

Because of their diversity, abundance, and complex morphology, fossil foraminiferal assemblages are useful for biostratigraphy, and can accurately give relative dates to rocks. The oil industry relies heavily on microfossils such as forams to find potential oil deposits.

Calcareous fossil Foraminifera are formed from elements found in the ancient seas they lived in. Thus they are very useful in paleoclimatology and paleoceanography. They can be used to reconstruct past climate by examining the stable isotope ratios of oxygen, and the history of the carbon cycle and oceanic productivity by examining the stable isotope ratios of carbon; see δ18O and δ13C. Geographic patterns seen in the fossil records of planktonic forams are also used to reconstruct ancient ocean currents. Because certain types of Foraminifera are found only in certain environments, they can be used to figure out the kind of environment under which ancient marine sediments were deposited.

For the same reasons they make useful biostratigraphic markers, living foraminiferal assemblages have been used as bioindicators in coastal environments, including indicators of coral reef health. Because calcium carbonate is susceptible to dissolution in acidic conditions, Foraminifera may be particularly affected by changing climate and ocean acidification.

Foraminifera have many uses in petroleum exploration and are used routinely to interpret the ages and paleoenvironments of sedimentary strata in oil wells. Agglutinated fossil Foraminifera buried deeply in sedimentary basins can be used to estimate thermal maturity, which is a key factor for petroleum generation. The Foraminiferal Colouration Index (FCI) is used to quantify colour changes and estimate burial temperature. FCI data is particularly useful in the early stages of petroleum generation (~100°C).

Foraminifera can also be utilised in archaeology in the provenancing of some stone raw material types. Some stone types, such as limestone, are commonly found to contain fossilised Foraminifera. The types and concentrations of these fossils within a sample of stone can be used to match that sample to a source known to contain the same "fossil signature".