View source for Physics:Oldest dated rocks

{{short description|Includes rocks over 4 billion years old from the Hadean Eon}}
[[Image:4,030,000,000 Years Acasta Gneiss.jpg|thumb|right|200px|A sample of gneiss from the site of the Earth's oldest dated rocks (the Acasta River area of Canada). This sample has been dated at 4.03 billion years old.]]
[[File:Big Bertha sample 14321.jpg|thumb|The Moon rock "Big Bertha", collected on the 1971 Apollo 14 mission, contains an Earth meteorite that is 4 billion years old.]]
The '''oldest dated rocks''' formed on [[Astronomy:Earth|Earth]], as an [[Earth:Aggregate (geology)|aggregate]] of minerals that have not been subsequently broken down by [[Earth:Erosion|erosion]] or melted, are more than 4 billion years old, formed during the [[Earth:Hadean|Hadean]] [[Earth:Eon (geology)|Eon]] of [[Earth:Geological history of Earth|Earth's geological history]]. Meteorites that were formed in other [[Astronomy:Planetary system|planetary system]]s can pre-date Earth. Particles from the [[Biology:Murchison meteorite|Murchison meteorite]] were dated in January 2020 to be 7 billion years old.<ref>{{Cite news |last=Lyons |first=Suzannah |title=Grains of stardust found in meteorite that landed in Victoria |website=ABC News (Australia) - Science|date=13 January 2020 |url=https://www.abc.net.au/news/science/2020-01-14/earths-oldest-stardust-found-in-murchison-meteorite/11863486 }}</ref>

Hadean [[Earth:Rock (geology)|rock]]s are exposed on Earth's surface in very few places, such as in the [[Earth:Shield (geology)|geologic shield]]s of [[Place:Canadian Shield|Canada]], [[Earth:Australia (continent)|Australia]], and [[Earth:Africa|Africa]]. The ages of these [[Earth:Felsic|felsic]] rocks are generally between 2.5 and 3.8 billion years. The approximate ages have a margin of error of millions of years. In 1999, the oldest known rock on Earth was dated to 4.031 ±0.003 billion years, and is part of the [[Earth:Acasta Gneiss|Acasta Gneiss]] of the Slave craton in northwestern Canada.<ref name="Bowring">{{cite journal | doi = 10.1007/s004100050465 | title = Priscoan (4.00–4.03 Ga) orthogneisses from northwestern Canada | year = 1999 | author = Bowring, Samuel A. | journal = Contributions to Mineralogy and Petrology | volume = 134 | issue = 1 | page = 3 | bibcode=1999CoMP..134....3B | last2 = Williams | first2 = Ian S.| s2cid = 128376754 }}</ref> Researchers at McGill University found a rock with a very old model age for extraction from the [[Earth:Mantle (geology)|mantle]] (3.8 to 4.28 billion years ago) in the Nuvvuagittuq greenstone belt on the coast of Hudson Bay, in northern Quebec;<ref>{{Cite web |title=Oldest Rocks on Earth Found |last=Thompson |first=Andrea |work=Live Science |date=25 September 2008 |url=https://www.livescience.com/2896-oldest-rocks-earth.html }}</ref> the true age of these samples is still under debate, and they may actually be closer to 3.8 billion years old.<ref name="Wilde">[https://www.newscientist.com/article/dn14818-discovery-of-worlds-oldest-rocks-challenged-.html Discovery of world's oldest rocks challenged]</ref> Older than these rocks are crystals of the mineral [[Chemistry:Zircon|zircon]], which can survive the disaggregation of their parent rock and be found and dated in younger rock formations.

In January 2019, [[Organization:NASA|NASA scientists]] reported the discovery of the oldest known Earth rock, found on the [[Astronomy:Moon|Moon]]. [[Engineering:Apollo 14|Apollo 14]] astronauts returned several rocks from the Moon and, later, scientists determined that a fragment from a rock nicknamed [[Astronomy:Big Bertha (lunar sample)|Big Bertha]], which had been chosen by astronaut Alan Shepard, contained "a bit of Earth from about 4 billion years ago". The rock fragment contained [[Chemistry:Quartz|quartz]], [[Chemistry:Feldspar|feldspar]], and zircon, all common on Earth, but highly uncommon on the Moon.<ref name="NASA-20190124" /> In January 2020, astronomers reported that the oldest material on Earth found so far are [[Biology:Murchison meteorite|Murchison meteorite]] particles that have been determined to be 7 billion years old, billions of years older than the 4.54 billion years age of Earth itself.<ref name="LS-20200113">{{cite news |last=Weisberger |first=Mindy |title=7 Billion-Year-Old Stardust Is Oldest Material Found on Earth - Some of these ancient grains are billions of years older than our sun. |url=https://www.livescience.com/oldest-material-on-earth.html |date=13 January 2020 |work=Live Science |access-date=13 January 2020 }}</ref><ref name="PNAS-20200113">{{cite journal |author=Heck, Philipp R. |display-authors=et al. |title=Lifetimes of interstellar dust from cosmic ray exposure ages of presolar silicon carbide |date=13 January 2020 |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=117 |issue=4 |pages=1884–1889 |doi=10.1073/pnas.1904573117 |pmid=31932423 |pmc=6995017 |bibcode=2020PNAS..117.1884H |doi-access=free }}</ref>

==Oldest rocks by category==
{{See|Hadean zircon}}
{{Life timeline}}
===Oldest terrestrial material===
The oldest material of terrestrial origin that has been [[Physics:Radiometric dating|dated]] is a [[Chemistry:Zircon|zircon]] mineral of 4.404 ±0.008 Ga enclosed in a [[Earth:Metamorphism|metamorphosed]] [[Earth:Sandstone|sandstone]] [[Earth:Conglomerate (geology)|conglomerate]] in the Jack Hills of the [[Earth:Narryer Gneiss Terrane|Narryer Gneiss Terrane]] of Western Australia.<ref name=wilde/> The 4.404 ±0.008 Ga zircon is a slight outlier, with the oldest consistently dated zircon falling closer to 4.35 Ga.<ref name=wilde>{{cite journal | last1=Wilde | first1=Simon A. | last2=Valley | first2=John W. | last3=Peck | first3=William H. | last4=Graham | first4=Colin M. | title=Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago (letter) | journal=Nature | volume=409 | issue=6817 | year=2001 | issn=0028-0836 | doi=10.1038/35051550 | pages=175–178 | pmid=11196637 | s2cid=4319774 | url=http://www.geology.wisc.edu/%7Evalley/zircons/Wilde2001Nature.pdf | archive-url=https://web.archive.org/web/20060901140950/http://www.geology.wisc.edu/%7Evalley/zircons/Wilde2001Nature.pdf | archive-date=1 September 2006 | access-date=20 December 2006 | url-status=bot: unknown }}</ref> This zircon is part of a population of zircons within the metamorphosed conglomerate, which is believed to have been deposited about 3.060&nbsp;Ga, which is the age of the youngest detrital zircon in the rock. Recent developments in [[Engineering:Atom probe|atom-probe tomography]] have led to a further constraint on the age of the oldest continental zircon, with the most recent age quoted as 4.374 ±0.006 Ga.<ref>{{cite journal | last1=Valley | first1=John W. | last2=Cavosie | first2=Aaron J. | last3=Ushikubo | first3=Takayuki | last4=Reinhard | first4=David A. | last5=Lawrence | first5=Daniel F. | last6=Larson | first6=David J. | last7=Clifton | first7=Peter H. | last8=Kelly | first8=Thomas F. | last9=Wilde | first9=Simon A. | last10=Moser | first10=Desmond E. | last11=Spicuzza | first11=Michael J. | title=Hadean age for a post-magma-ocean zircon confirmed by atom-probe tomography | journal=Nature Geoscience | volume=7 | issue=3 | date=23 February 2014 | issn=1752-0894 | doi=10.1038/ngeo2075 | pages=219–223| bibcode=2014NatGe...7..219V }}</ref>

The discovery of the oldest known Earth rock, found on the Moon, was reported in January 2019 by [[Organization:NASA|NASA scientists]]. [[Engineering:Apollo 14|Apollo 14]] astronauts returned several rocks from the Moon and, later, scientists determined that a fragment from one of the rocks, nicknamed [[Astronomy:Big Bertha (lunar sample)|Big Bertha]], contained "a bit of Earth from about 4 billion years ago". The rock fragment contained [[Chemistry:Quartz|quartz]], [[Chemistry:Feldspar|feldspar]], and [[Chemistry:Zircon|zircon]], all common on Earth, but highly uncommon on the Moon.<ref name="NASA-20190124">{{cite news |author=[[Organization:Universities Space Research Association|Universities Space Research Association]] (USRA) |title=Earth's Oldest Rock Found on the Moon |url=https://solarsystem.nasa.gov/news/820/earths-oldest-rock-found-on-the-moon/ |date=24 January 2019 |work=[[Organization:NASA|NASA]] |access-date=25 January 2019 }}</ref>

===Earth's oldest rock formation===
The oldest outcropping rock formation is, depending on the latest research, either part of the Isua Greenstone Belt, [[Earth:Narryer Gneiss Terrane|Narryer Gneiss Terrane]], Nuvvuagittuq Greenstone Belt, Napier Complex, or the [[Earth:Acasta Gneiss|Acasta Gneiss]] (on the [[Earth:Slave Craton|Slave Craton]]). The difficulty in assigning the title to one particular block of gneiss is that the [[Earth:Gneiss|gneiss]]es are all extremely deformed, and the oldest rock may be represented by only one streak of minerals in a [[Earth:Mylonite|mylonite]], representing a layer of sediment or an old [[Earth:Dike (geology)|dike]]. This may be difficult to find or map; hence, the oldest dates yet resolved are as much generated by luck in sampling as by understanding the rocks themselves.

It is thus premature to claim that any of these rocks, or indeed that of other formations of Hadean gneisses, is the oldest formations or rocks on Earth; doubtless, new analyses will continue to change conceptions of the structure and nature of these ancient continental fragments.

Nevertheless, the oldest cratons on Earth include the Kaapvaal Craton, the Western Gneiss Terrane of the [[Earth:Yilgarn Craton|Yilgarn Craton]] (~2.9 – >3.2 Ga), the [[Earth:Pilbara Craton|Pilbara Craton]] (~3.4 Ga), and portions of the Canadian Shield (~2.4 – >3.6 Ga). Parts of Dharwar Craton in India are greater than 3.0 Ga. The oldest dated rocks of the [[Place:Baltic Shield|Baltic Shield]] are 3.5 Ga old.<ref>{{Cite journal|first1=Tapani|last1=Mutanen|first2=Hannu|last2=Huhma|title=The 3.5 Ga Siurua trondhjemite gneiss in the Archaean Pudasjärvi Granulite Belt, northern Finland|journal=Bulletin of the Geological Society of Finland|url=https://www.geologinenseura.fi/sites/geologinenseura.fi/files/mutanenhuhma.pdf|volume=75|year=2003|issue=1–2|pages=51–68|doi=10.17741/bgsf/75.1-2.004}}</ref>

Other old formations include the Saglek Gneiss Complex, dated at 3.8-3.9 Ga; the Anshan Area, dated at 3.8 Ga; the Itsaq (Isua) Gneiss Complex, dated at 3.7-3.8 Ga; and the Ancient Gneiss Complex, dated at 3.6 Ga.

===Oldest rock on Earth===
[[File:Acasta Gneiss fragment.JPG|thumb|left|150px|Fragment of Acasta Gneiss]]
The [[Earth:Acasta Gneiss|Acasta Gneiss]] in the Canadian Shield in the [[Earth:Northwest Territories|Northwest Territories]], Canada is composed of the [[Earth:Archean|Archaean]] igneous and [[Earth:Gneiss|gneiss]]ic cores of ancient mountain chains that have been exposed in a [[Earth:Glacier|glacial]] [[Earth:Peneplain|peneplain]]. Analyses of zircons from a felsic orthogneiss with presumed granitic protolith returned an age of 4.031 ±0.003 Ga.<ref name="Bowring"/>

On September 25, 2008, researchers from McGill University, [[Organization:Carnegie Institution for Science|Carnegie Institution for Science]] and UQAM announced that a rock formation, the Nuvvuagittuq greenstone belt, exposed on the eastern shore of Hudson Bay in northern Quebec had a Sm–Nd model age for extraction from the mantle of 4.28 billion years.<ref name="4.28">{{cite journal | doi = 10.1126/science.1161925 |date=Sep 2008 |author1=O'Neil, J |author2=Carlson, Rw |author3=Francis, D |author4=Stevenson, Rk | title = Neodymium-142 evidence for Hadean mafic crust | volume = 321 | issue = 5897 | pages = 1828–31 | pmid = 18818357 | journal = Science|bibcode = 2008Sci...321.1828O |s2cid=206514655 }}</ref><ref name="McGill Greenstone Press release" >[https://www.mcgill.ca/newsroom/news/item/?item_id=102000 McGill University press release] {{Closed access}}</ref><ref name="MSNBC Oldest Rocks found">[http://www.nbcnews.com/id/26890176 Oldest rocks on Earth found]</ref><ref>http://www.sciencemag.org/cgi/reprint/321/5897/1828.pdf {{Dead link|date=January 2022|fix-attempted=yes}}</ref> However, it is argued that the actual age of formation of this rock, as opposed to the extraction of its magma from the mantle, is likely closer to 3.8 billion years, according to Simon Wilde of the Institute for Geoscience Research in Australia.<ref name="Wilde"/>

===2008 microprobe research===
The zircons from the Western Australian Jack Hills returned an age of 4.404 billion years, interpreted to be the age of crystallization. These zircons also show another feature; their oxygen isotopic composition has been interpreted to indicate that more than 4.4 billion years ago there was already water on the surface of Earth. The importance and accuracy of these interpretations is currently the subject of scientific debate. It may be that the oxygen isotopes and other compositional features (the [[Chemistry:Rare-earth element|rare-earth element]]s) record more recent hydrothermal alteration of the zircons rather than the composition of the magma at the time of their original crystallization.{{Citation needed|date=November 2007}} In a paper published in the journal ''Earth and Planetary Science Letters'', a team of scientists suggest that rocky continents and liquid water existed at least 4.3 billion years ago and were subjected to heavy weathering by an acrid climate. Using an [[Physics:Sensitive high-resolution ion microprobe|ion microprobe]] to analyze isotope ratios of the element lithium in zircons from the Jack Hills in Western Australia, and comparing these chemical fingerprints to lithium compositions in zircons from continental crust and primitive rocks similar to Earth's mantle, they found evidence that the young planet already had the beginnings of continents, relatively cool temperatures and liquid water by the time the Australian zircons formed.<ref>[http://newswise.com/articles/view/541751/ Newswise: Ancient Mineral Shows Early Earth Climate Tough on Continents]. Retrieved June 15, 2008.</ref>
[[File:Main mass of the Northwest Africa (NWA) 11119 meteorite.png|thumb|The main mass of NWA 11119 found in Mauritania in December 2016. It is the first, and oldest, silica-rich ([[Earth:Andesite|andesitic]] to dacitic) porphyritic extrusive crustal rock with an Al–Mg age of 4564.8 (± 0.3) Ma.]]

=== Non-terrestrial rocks ===
Meteorites can be even older; in January 2020, astronomers reported that the oldest material on Earth found so far are [[Biology:Murchison meteorite|Murchison meteorite]] particles that have been determined to be 7 billion years old, 2.5 billion years older than the Sun itself (which formed about 4.56 billion years ago).<ref name="LS-20200113"/><ref name="PNAS-20200113"/>

One of the oldest [[Astronomy:Martian meteorite|Martian meteorite]]s found on Earth, [[Astronomy:Allan Hills 84001|Allan Hills 84001]], discovered in the Allan Hills of [[Earth:Antarctica|Antarctica]], has been reported to have crystallized from molten rock 4.091 billion years ago.<ref name="age3">{{Cite journal|last1=Lapen|first1=T. J.|year=2010|title=A Younger Age for ALH84001 and Its Geochemical Link to Shergottite Sources in Mars|journal=Science|volume=328|issue=5976|pages=347–351|doi=10.1126/science.1185395|pmid=20395507|bibcode = 2010Sci...328..347L |last2=Righter|first2=M.|last3=Brandon|first3=A. D.|last4=Debaille|first4=V.|last5=Beard|first5=B. L.|last6=Shafer|first6=J. T.|last7=Peslier|first7=A. H.|s2cid=17601709|display-authors=1}}</ref>

The Genesis Rock (Lunar sample 15415), obtained from the [[Astronomy:Moon|Moon]] by astronauts during [[Engineering:Apollo 15|Apollo 15]] mission, has been dated at 4.08 billion years.<ref name="NASA-2011">{{cite web |last=Meyer |first=C. |title=Lunar Sample Compendium - 15415 Ferroan Anorthosite |url=http://curator.jsc.nasa.gov/lunar/lsc/15415.pdf |year=2011 |work=[[Organization:NASA|NASA]] |access-date=July 24, 2017 }}</ref> During [[Engineering:Apollo 16|Apollo 16]], older rocks, including Lunar sample 67215, dated at 4.46 billion years, were brought back.<ref>{{cite journal | last1=Norman | first1=Marc D. | last2=Borg | first2=Lars E. | last3=Nyquist | first3=Lawrence E. | last4=Bogard | first4=Donald D. | title=Chronology, geochemistry, and petrology of a ferroan noritic anorthosite clast from Descartes breccia 67215: Clues to the age, origin, structure, and impact history of the lunar crust | journal=Meteoritics & Planetary Science | publisher=Wiley | volume=38 | issue=4 | year=2003 | issn=1086-9379 | doi=10.1111/j.1945-5100.2003.tb00031.x |doi-access=free| pages=645–661| bibcode=2003M&PS...38..645N }} [http://www.psrd.hawaii.edu/April04/lunarAnorthosites.html Summary]</ref>

A volcanic meteorite Northwest Africa (NWA) 11119 found in Mauritania in December 2016 has been dated to 4.5648 ± 0.0003 billion years.<ref name=Srinivasan>{{cite journal |last1=Srinivasan |first1=Poorna |last2=Dunlap |first2=Daniel R |last3=Agee |first3=Carl B|last4=Wadhwa |first4=Meenakshi |author4-link=Meenakshi Wadhwa |last5=Coleff |first5=Daniel |last6=Ziegler |first6=Karen |last7=Zeigler  |first7=Ryan |last8=McCubbin |first8=Francis M.|date=2 August 2018 |title=Silica-rich volcanism in the early solar system dated at 4.565 Ga |journal=Nature Communications  |volume=9 |issue=1 |pages=3036 |doi=10.1038/s41467-018-05501-0  |pmid=30072693 |pmc=6072707 |bibcode=2018NatCo...9.3036S }} {{open access}}</ref>

==See also==
* {{annotated link|Earth:Age of Earth}}
* {{annotated link|Biology:Earliest known life forms}}
* {{annotated link|Earth:History of Earth}}
* Nature timeline

==References==
{{reflist|colwidth=30em}}

==Bibliography==
* [http://www.geology.wisc.edu/zircon/zircon_home.html Zircons are Forever] {{Webarchive|url=https://web.archive.org/web/20070412195510/http://www.geology.wisc.edu/zircon/zircon_home.html |date=2007-04-12 }}
* {{cite web |url=http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17201 | archive-url=https://web.archive.org/web/20061001054409/http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17201 | url-status=dead | archive-date=2006-10-01 | title=Western Australia's Jack Hills | work=[[Astronomy:NASA Earth Observatory|NASA Earth Observatory]] newsroom | access-date=2006-04-28}}
* Bowring, S.A., and Williams, I.S., 1999. Priscoan (4.00–4.03 Ga) orthogneisses from northwestern Canada. Contributions to Mineralogy and Petrology, v. 134, 3–16.
* Stern, R.A., Bleeker, W., 1998. Age of the world's oldest rocks refined using Canada's SHRIMP. the Acasta gneiss complex, Northwest Territories, Canada. Geoscience Canada, v. 25, pp.&nbsp;27–31
* Yu A., Lee C-D and Halliday, A. N.''Lutetium-Hafnium and Uranium-Lead Systematics of Early-Middle Archean Single Zircon Grains'', Ninth Annual Goldschmidt Conference. [http://www.lpi.usra.edu/meetings/gold99/pdf/7202.pdf 2]

==External links==
*[http://records.viu.ca/~earles/zircon-jan01.htm Very old Australian zircons with a story to tell] {{Webarchive|url=https://web.archive.org/web/20090627143131/http://records.viu.ca/~earles/zircon-jan01.htm |date=2009-06-27 }}
*[https://web.archive.org/web/20061210111551/http://www.nmnh.si.edu/paleo/geotime/main/hadean4.html On the Acasta Gneiss]
*[http://www.sciencemag.org/cgi/content/abstract/321/5897/1828 Abstract and full text of the results from O'Neil's research, published by Science]

[[Category:Petrology]]
[[Category:Radiometric dating]]

{{Sourceattribution|Oldest dated rocks}}