What is micropaleontology?

Micropaleontology is the field of study dealing with small fossils that are best studied with a microscope. Microfossils include a wide variety of microscopic remains of single-celled organisms, plants, and animals.

Types of Microfossils

Some are from microscopic plant-like organisms; some are from microscopic animal-like organisms; some are from land plants; some are from marine creatures.

Foraminifera Foraminifera are tiny, amoeba-like single-celled organisms that commonly have shells. They are characterized by thread-like extensions of their protoplasm called reticulating pseudopodia. They typically live in marine environments, some types on the bottom (benthic) and some in the water column (planktic). Their shells may be preserved in sediments and thus provide a record of past environments. Many species are also useful biostratigraphic indicators, which provide en estimate of a sediment's age. More information is available at the University of California Museum of Paleontology web site.

OstracodaOstracodes are small, bivalved crustaceans that may range from a fraction of a millimeter to many millimeters in size. They have a long geologic history, ranging back into the Paleozoic Era, with a wide variety of species occupying a wide range of environments, from oceans to bays to lakes to soils. Their shells are readily fossilized, making them useful for biostratigraphy and paleoenvironmental analyses. More information is available at the University of California Museum of Paleontology web site.

ConodontsConodonts are small, tooth-like phosphatic microfossils found in sedimentary rocks from the Paleozoic Era (and earliest Mesozoic Era). They are thought to be produced by an extinct jawless chordate that had some resemblance to eels. They are valuable biostratigraphic indicators; in addition, their color may be used to indicate the thermal history of s sedimentary rock. More information is available at the University College London web site.

Pollen and Spores Pollen and spores provide a record of plant life in the past. Pollen are tiny grains produced by seed plants that contain the male reproductive cells of the plant. The organic-walled remains of pollen grains can be preserved in sediments and fossilized. Spores of non-seed producing plants such as ferns may also be preserved as organic-walled fossils. Because these types of grains may be produced in abundance by some land plants, palynology (the study of pollen, spores, and other organic-walled microfossils) can be useful for biostratigraphy and climate reconstruction, particularly in non-marine sediments. More information is available at the University of Arizona web site.

NannofossilsNannofossils are the hard parts of single-celled golden-brown algae. These hard parts are extremely small calcite plates (called coccoliths) that are secreted by the algae as it grows. Calcareous nannofossils can be very abundant in the sediments at the bottom of the oceans of today and the past. More information is available at the US Geological Survey web page on nannofossils. DinoflagellatesDinoflagellates are a group of single-celled, flagellated algae, some of which are preserved as organic-walled microfossils; as such, they are included in the field of palynology. Dinoflagellates mostly live in marine environments Their fossils are useful for biostratigraphy and interpretation of coastal and oceanic paleoenvironments. More information is available at University of California Museum of Paleontology web site.
RadiolariaRadiolaria are minute, amoeba-like single-celled planktonic marine organisms that have intricate shells usually made of opaline silica. Their shells in ocean bottom sediments provide a useful record of climate and oceanography. More information is available at the web site radiolaria.org. OthersThere are a number of other useful microfossil groups studied by micropaleontologists - diatoms, silicoflagellates, chitinozoans, among them. A search engine should yield a number of sites with helpful information.

How Microfossils Are Used

Microfossils are an important tool for understanding the age and environment of deposition of sedimentary rocks. Because of their small size, they may occur in great numbers in small samples, such as those collected from oil wells, making them very useful in petroleum exploration and production.

Some useful web sites that explain applications of micropaleontolgy include:


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The North American Micropaleontology Section of SEPM