Micropaleontology

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Marine microfossils: (diatom, ostracod, radiolarian, sponge spicule, radiolarian, planktonic foraminiferan (two), coccolith)
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Micropaleontology (American spelling; spelled micropalaeontology in European usage) is the branch of

palaeontology) that studies microfossils
, or fossils that require the use of a microscope to see the organism, its morphology and its characteristic details.

Microfossils

μm, the entire image covers a region of approximately 1.13 by 0.69 mm
.
Main article: Microfossil

fossils that are generally between 0.001mm and 1 mm in size,[1] the study of which requires the use of light or electron microscopy. Fossils which can be studied by the naked eye or low-powered magnification, such as a hand lens, are referred to as macrofossils
.

For example, some colonial organisms, such as

Cheilostomata) have relatively large colonies
, but are classified by fine skeletal details of the small individuals of the colony.

In another example, many fossil

Nummulites
.

Microfossils are a common feature of the

spores from the vascular plants
.

In 2017, fossilized

formation of the Earth 4.54 billion years ago.[2][3][4][5] Nonetheless, life may have started even earlier, at nearly 4.5 billion years ago, as claimed by some researchers.[6][7]

Areas of study

Triticites) from the Plattsmouth Chert, Red Oak, Iowa (Permian
).

Micropaleontology can be roughly divided into four areas of study on the basis of microfossil composition: (a)

spores studied in palynology
.

This division reflects differences in the mineralogical and chemical composition of microfossil remains (and therefore in the methods of fossil recovery) rather than any strict

ecological distinctions. Most researchers in this field, known as micropaleontologists, are typically specialists in one or more taxonomic groups
.

Calcareous microfossils

See also: Calcareous nannofossils
nummulitid foraminiferans showing microspheric and megalospheric individuals; Eocene of the United Arab Emirates
; scale in mm.

Calcareous (CaCO3) microfossils include coccoliths, foraminifera, calcareous dinoflagellate cysts, and ostracods (seed shrimp).

Phosphatic microfossils

scolecodonts ("worm" jaws), Shark spines and teeth, and other Fish remains (collectively called "ichthyoliths
").

Siliceous microfossils

scolecodonts ("worm" jaws), and sponge spicules
.

Organic microfossils

The study of

fungal
remains.

Methods

Sediment or rock samples are collected from either cores or outcrops, and the microfossils they contain are extracted by a variety of physical and chemical laboratory techniques, including sieving, density separation by centrifuge or in heavy liquids, and chemical digestion of the unwanted fraction. The resulting concentrated sample of microfossils is then mounted on a slide for analysis, usually by light microscope. Taxa are then identified and counted. The enormous numbers of microfossils that a small sediment sample can often yield allows the collection of statistically robust datasets which can be subjected to multivariate analysis. A typical microfossil study will involve identification of a few hundred specimens from each sample.

Application of micropaleontology

Microfossils are specially noteworthy for their importance in

nektonic habits of some microfossils give them the bonus of appearing across a wide range of facies
or paleoenvironments, as well as having near-global distribution, making biostratigraphic correlation even more powerful and effective.

Microfossils, particularly from deep-sea sediments, also provide some of the most important records of global environmental change on long, medium or short timescales.[8] Across vast areas of the ocean floor, the shells of planktonic micro-organisms sinking from surface waters provide the dominant source of sediment, and they continuously accumulate (typically at rates of 20–50 million per million years). Study of changes in assemblages of microfossils and changes in their shell chemistry (e.g., oxygen isotope composition) are fundamental to research on climate change in the geological past.

In addition to providing an excellent tool for

archaeological
artefacts.

Micropaleontology is also a tool of

ostracods in freshwater bodies are impacted by changes in salinity and pH due to human activities. When correlated with other dating techniques, prehistoric environments can be reconstructed. Work on Lake Tanganyika provided a profile of human-induced environmental changes of a 4,000-year period.[9]

Similar work in the arid American Southwest has provided information on irrigation

canals used by prehistoric peoples from 2100 B.C. to 500 B.C.[10]
Other archaeological work in arid climates throughout the Americas has incorporated Micropaleontological analysis to build a more complete picture of prehistoric climate and human activity.

See also

References

  1. ^ Drewes, Charlie. "Discovering Devonian Microfossils" (PDF). Iowa State University. Archived from the original (PDF) on 7 January 2023. Retrieved 7 January 2023.
  2. PMID 28252057. Archived
    (PDF) from the original on 23 July 2018. Retrieved 15 February 2019.
  3. New York Times. Archived
    from the original on 2 March 2017. Retrieved 2 March 2017.
  4. ^ Ghosh, Pallab (1 March 2017). "Earliest evidence of life on Earth 'found". BBC News. Archived from the original on 2 March 2017. Retrieved 2 March 2017.
  5. ^ Dunham, Will (1 March 2017). "Canadian bacteria-like fossils called oldest evidence of life". Reuters. Archived from the original on 2 March 2017. Retrieved 1 March 2017.
  6. ^ Staff (20 August 2018). "A timescale for the origin and evolution of all of life on Earth". Phys.org. Archived from the original on 3 March 2021. Retrieved 20 August 2018.
  7. PMID 30127539
    .
  8. ISBN 978-5-02-035758-7 [1]
  9. S2CID 129499529. Archived from the original
    (PDF) on 2011-07-17.
  10. ^ M. Palacios-Fest & Owen K. Davis (2008). "8" (PDF). Las Capas: Early Irrigation and Sedentism in a Southwestern Floodplain. Center for Desert Archaeology, Tucson, Arizona, USA. pp. 197–220. Archived from the original (PDF) on 2011-07-17. {{cite book}}: |work= ignored (help)

Further reading

External links

Wikimedia Commons has media related to Microfossils.
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