9.5: Microfossils
Major Microfossil Groups
Microfossils are fossils that are less then 2 mm in size and require the aid of a microscope to study. Many taxonomic groups are represented in the microfossil record but here we will focus on some of the common mineralized microfossil groups. These include foraminifera , radiolarians , diatoms , ostracods , and conodonts . These microfossils are important tools for biostratigraphy and paleoclimatology. Other notable nonmineralized microfossils include spores and pollen .
Foraminifera
Foraminifera are an Order of single celled protista that have an extensive fossil record. These organism are aquatic and live inside a shell referred to as a test. Classification of the foraminifera genera is based on shell mineralogy, shell morphology, and internal shell structure. Foraminifera with shells composed of calcium carbonate are more readily preserved than organic (chitin) based groups and make up the bulk of the foraminifera fossil record. Some common fossil forming Genera are Textulariids, Fusulinids, Miliolids, Rotaliids, and Globigerinids. For more information please visit the Digital Atlas of Ancient Life's foraminifera webpage .
Most foraminifera are marine but there are a few freshwater varieties. The group ranges from the Cambrian to the present.