Editing Microfossil (section)

==Overview==
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A microfossil is a descriptive term applied to fossilized plants and animals whose size is just at or below the level at which the fossil can be analyzed by the naked eye. A commonly applied cutoff point between "micro" and [[macrofossil|"macro" fossils]] is 1&nbsp;mm. Microfossils may either be complete (or near-complete) organisms in themselves (such as the marine plankters [[foraminifera]] and [[coccolithophore]]s) or component parts (such as small teeth or [[palynology|spores]]) of larger animals or plants. Microfossils are of critical importance as a reservoir of [[Paleoclimatology|paleoclimate]] information, and are also commonly used by [[biostratigraphy|biostratigraphers]] to assist in the correlation of rock units.

Microfossils are found in rocks and sediments as the microscopic remains of what were once life forms such as plants, animals, fungus, protists, bacteria and archaea. Terrestrial microfossils include [[pollen]] and [[spore]]s. Marine microfossils found in [[marine sediment]]s are the most common microfossils. Everywhere in the oceans, microscopic [[Marine protists|protist organisms]] multiply prolifically, and many grow [[Protist shell|tiny skeletons]] which readily fossilise. These include [[foraminifera]], [[dinoflagellate]]s and [[radiolarian]]s. [[Palaeontologist]]s (geologists who study fossils) are interested in these microfossils because they can use them to determine how environments and climates have changed in the past, and where oil and gas can be found today.<ref name=Campbell2006>Campbell, Hamish (12 Jun 2006) [https://teara.govt.nz/en/fossils/page-7#:~:text=Microfossils%20are%20the%20remains%20of,use%20microscopes%20to%20study%20them. "Fossils - Microfossils"], ''Te Ara - the Encyclopedia of New Zealand". Accessed 11 May 2021.</ref>

Some microfossils are formed by [[colonial organism]]s such as [[Bryozoa]] (especially the [[Cheilostomata]]), which have relatively large [[colony (biology)|colonies]] but are classified by fine skeletal details of the small individuals of the colony. As another example, many fossil [[genus|genera]] of [[Foraminifera]], which are protists are known from shells (called [[Test (biology)|tests]]) that were as big as coins, such as the genus ''[[Nummulites]]''.

In 2017, fossilized [[microorganism]]s, or microfossils, were discovered in [[hydrothermal vent]] [[precipitates]] in the [[Nuvvuagittuq Greenstone Belt|Nuvvuagittuq Belt]] of Quebec, Canada that may be as old as 4.28 billion years old, the [[Earliest known life forms|oldest record of life on Earth]], suggesting "an almost instantaneous emergence of life" (in a geological time-scale), after [[Origin of water on Earth#History of water on Earth|ocean formation 4.41 billion years ago]], and not long after the [[Age of the Earth|formation of the Earth]] 4.54 billion years ago.<ref name="NAT-20170301">{{cite journal |author=Dodd, Matthew S. |author2=Papineau, Dominic |author3=Grenne, Tor |author4=slack, John F. |author5=Rittner, Martin |author6=Pirajno, Franco |author7=O'Neil, Jonathan |author8=Little, Crispin T. S. |title=Evidence for early life in Earth's oldest hydrothermal vent precipitates|journal=Nature |volume=543 |issue=7643 |pages=60–64 |date=2 March 2017 | doi=10.1038/nature21377|pmid=28252057 |bibcode=2017Natur.543...60D |url=http://eprints.whiterose.ac.uk/112179/1/ppnature21377_Dodd_for%20Symplectic.pdf |doi-access=free }}</ref><ref name="NYT-20170301">{{cite news |last=Zimmer |first=Carl |author-link=Carl Zimmer |title=Scientists Say Canadian Bacteria Fossils May Be Earth's Oldest |url=https://www.nytimes.com/2017/03/01/science/earths-oldest-bacteria-fossils.html |date=1 March 2017 |work=[[New York Times]] |access-date=2 March 2017 }}</ref><ref name="BBC-20170301">{{cite web |last=Ghosh |first=Pallab |title=Earliest evidence of life on Earth 'found |url=https://www.bbc.co.uk/news/science-environment-39117523 |work=[[BBC News]] |date=1 March 2017 |access-date=2 March 2017}}</ref><ref name="4.3b oldest">{{cite news |last1=Dunham |first1=Will |title=Canadian bacteria-like fossils called oldest evidence of life |url=http://ca.reuters.com/article/topNews/idCAKBN16858B?sp=true |archive-url=https://web.archive.org/web/20170302114728/http://ca.reuters.com/article/topNews/idCAKBN16858B?sp=true |url-status=dead |archive-date=2 March 2017 |date=1 March 2017 |publisher=[[Reuters]] |access-date=1 March 2017 }}</ref> Nonetheless, life may have started even earlier, at nearly 4.5 billion years ago, as claimed by some researchers.<ref name="PHY-20180820">{{cite web |author=Staff |title=A timescale for the origin and evolution of all of life on Earth |url=https://phys.org/news/2018-08-timescale-evolution-life-earth.html |date=20 August 2018 |work=[[Phys.org]] |access-date=20 August 2018 }}</ref><ref name="NAT-20180820">{{cite journal |last1=Betts |first1=Holly C. |last2=Putick |first2=Mark N. |last3=Clark |first3=James W. |last4=Williams |first4=Tom A. |last5=Donoghue |first5=Philip C.J. |last6=Pisani |first6=Davide |title=Integrated genomic and fossil evidence illuminates life's early evolution and eukaryote origin |date=20 August 2018 |journal=[[Nature (journal)|Nature]] |volume=2 |issue=10 |pages=1556–1562 |doi=10.1038/s41559-018-0644-x |pmid=30127539 |pmc=6152910 }}</ref>

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