The oldest dated rocks formed on

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

, as an aggregate of

minerals In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): M ...

that have not been subsequently broken down by

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

or melted, are more than 4 billion years old, formed during the

Hadean The Hadean ( ) is the first and oldest of the four geologic eons of Earth's history, starting with the planet's formation about 4.6 billion years ago (estimated 4567.30 ± 0.16 million years ago set by the age of the oldest solid material ...

Eon of Earth's geological history, and mark the start of the

Archean The Archean ( , also spelled Archaean or Archæan), in older sources sometimes called the Archaeozoic, is the second of the four geologic eons of Earth's history of Earth, history, preceded by the Hadean Eon and followed by the Proterozoic and t ...

Eon, which is defined to start with the formation of the oldest intact rocks on Earth. Archean rocks are exposed on Earth's surface in very few places, such as in the geologic shields of

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, and

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

. The ages of these

felsic In geology, felsic is a grammatical modifier, modifier describing igneous rocks that are relatively rich in elements that form feldspar and quartz.Marshak, Stephen, 2009, ''Essentials of Geology,'' W. W. Norton & Company, 3rd ed. It is contrasted ...

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

Acasta Gneiss The Acasta Gneiss Complex, also called the Acasta Gneiss, is a body of felsic to Ultramafic rock, ultramafic Archean Basement (geology), basement rocks, gneisses, that form the northwestern edge of the Slave craton, Slave Craton in the Northwes ...

of the Slave Craton in northwestern Canada. Researchers at

McGill University McGill University (French: Université McGill) is an English-language public research university in Montreal, Quebec, Canada. Founded in 1821 by royal charter,Frost, Stanley Brice. ''McGill University, Vol. I. For the Advancement of Learning, ...

found a rock with a very old model age for extraction from the mantle (3.8 to 4.28 billion years ago) in the Nuvvuagittuq greenstone belt on the coast of

Hudson Bay Hudson Bay, sometimes called Hudson's Bay (usually historically), is a large body of Saline water, saltwater in northeastern Canada with a surface area of . It is located north of Ontario, west of Quebec, northeast of Manitoba, and southeast o ...

, in northern

Quebec Quebec is Canada's List of Canadian provinces and territories by area, largest province by area. Located in Central Canada, the province shares borders with the provinces of Ontario to the west, Newfoundland and Labrador to the northeast, ...

; the true age of these samples is still under debate, and they may actually be closer to 3.8 billion years old.Discovery of world's oldest rocks challenged
/ref> Older than these rocks are crystals of the mineral

zircon Zircon () is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is Zr SiO4. An empirical formula showing some of th ...

, which can survive the disaggregation of their parent rock and be found and dated in younger rock formations. In January 2019, NASA scientists reported the discovery of the oldest known Earth rock, found on the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

Apollo 14 Apollo 14 (January 31February 9, 1971) was the eighth crewed mission in the United States Apollo program, the third to Moon landing, land on the Moon, and the first to land in the Geology of the Moon#Highlands, lunar highlands. It was the las ...

astronauts returned several rocks from the Moon and, later, scientists determined that a fragment from a rock nicknamed Big Bertha, which had been chosen by astronaut

Alan Shepard Alan Bartlett Shepard Jr. (November 18, 1923 – July 21, 1998) was an American astronaut. In 1961, he became the second person and the first American to travel into space and, in 1971, he became the List of Apollo astronauts#Apollo astr ...

, contained "a bit of Earth from about 4 billion years ago". The rock fragment contained

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

feldspar Feldspar ( ; sometimes spelled felspar) is a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagiocl ...

, and zircon, all common on Earth, but highly uncommon on the Moon. Pre-solar grains in

meteorites A meteorite is a rock that originated in outer space and has fallen to the surface of a planet or moon. When the original object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheri ...

are older than the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...

, with some grains extracted from the

Murchison meteorite The Murchison meteorite is a meteorite that fell in Australia in 1969 near Murchison, Victoria. It belongs to the carbonaceous chondrite class, a group of meteorites rich in organic compounds. Due to its mass (over ) and the fact that it was ...

claimed to be 7 billion years old.

Oldest rocks by category

Oldest terrestrial material

The oldest material of terrestrial origin that has been dated is a

mineral of 4.404 ±0.008 Ga enclosed in a

metamorphosed Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causi ...

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

conglomerate in the Jack Hills of the Narryer Gneiss terrane of

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

. The 4.404 ±0.008 Ga zircon is a slight outlier, with the oldest consistently dated zircon falling closer to 4.35 Ga. This zircon is part of a population of zircons within the metamorphosed conglomerate, which is believed to have been deposited about 3.060 Ga, which is the age of the youngest detrital zircon in the rock. Recent developments in 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. The discovery of the oldest known Earth rock, found on the Moon, was reported in January 2019 by NASA scientists.

astronauts returned several rocks from the Moon and, later, scientists determined that a fragment from one of the rocks, nicknamed Big Bertha, contained "a bit of Earth from about 4 billion years ago". The rock fragment contained

, and

, all common on Earth, but highly uncommon on the Moon.

Earth's oldest rock formation

The oldest outcropping rock formation is, depending on the latest research, either part of the Isua Greenstone Belt, Narryer Gneiss terrane, Nuvvuagittuq Greenstone Belt, Napier Complex, or the

(on the Slave Craton). The difficulty in assigning the title to one particular block of gneiss is that the

gneiss Gneiss (pronounced ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. This rock is formed under p ...

es are all extremely deformed, and the oldest rock may be represented by only one streak of minerals in a

mylonite Mylonite is a fine-grained, compact metamorphic rock produced by dynamic recrystallization of the constituent minerals resulting in a reduction of the grain size of the rock. Mylonites can have many different mineralogical compositions; it is a ...

, representing a layer of sediment or an old 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 Yilgarn craton (~2.9 – >3.2 Ga), the 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

Baltic Shield The Baltic Shield (or Fennoscandian Shield) is a segment of the Earth's crust belonging to the East European craton, East European Craton, representing a large part of Fennoscandia, northwestern Russia and the northern Baltic Sea. It is composed ...

are 3.5 Ga old. 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

The

in the Canadian Shield in the

Northwest Territories The Northwest Territories is a federal Provinces and territories of Canada, territory of Canada. At a land area of approximately and a 2021 census population of 41,070, it is the second-largest and the most populous of Provinces and territorie ...

, Canada is composed of the Archaean

igneous Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial ...

and

ic cores of ancient mountain chains that have been exposed in a

glacial A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

peneplain. Analyses of zircons from a felsic orthogneiss with presumed granitic protolith returned an age of 4.031 ±0.003 Ga. On September 25, 2008, researchers from

Carnegie Institution for Science The Carnegie Institution for Science, also known as Carnegie Science and the Carnegie Institution of Washington, is an organization established to fund and perform scientific research in the United States. This institution is headquartered in W ...

and UQAM announced that a rock formation, the Nuvvuagittuq greenstone belt, exposed on the eastern shore of

in northern

had a Sm–Nd model age for extraction from the mantle of 4.28 billion years.McGill University press release
Oldest rocks on Earth found
/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.

Hadean Zircons from the Jack Hills of Western Australian

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

rare-earth element The rare-earth elements (REE), also called the rare-earth metals or rare earths, and sometimes the lanthanides or lanthanoids (although scandium and yttrium, which do not belong to this series, are usually included as rare earths), are a set o ...

s) record more recent

hydrothermal alteration Metasomatism (from the Greek μετά ''metá'' "change" and σῶμα ''sôma'' "body") is the chemical alteration of a Rock (geology), rock by hydrothermal and other fluids. It is traditionally defined as metamorphism which involves a change in t ...

of the zircons rather than the composition of the magma at the time of their original crystallization. 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 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.

Non-terrestrial rocks

One of the oldest

Martian meteorite A Martian meteorite is a rock that formed on Mars, was ejected from the planet by an impact event, and traversed interplanetary space before landing on Earth as a meteorite. , 277 meteorites had been classified as Martian, less than half a perce ...

s found on Earth,

Allan Hills 84001 Allan Hills 84001 (ALH84001) is a fragment of a Martian meteorite that was found in the Allan Hills in Antarctica on December 27, 1984, by a team of American meteorite hunters from the ANSMET project. Like other members of the shergottite– n ...

has been measured to have crystallized from molten rock 4.091 billion years ago. The

Genesis Rock The Genesis Rock (sample 15415) is a sample of Moon rock retrieved by Apollo 15 astronauts James Irwin and David Scott in 1971 during the second lunar extravehicular activity, EVA, at Spur (lunar crater), Spur crater on Earth's Moon. With a mass ...

(Lunar sample 15415), obtained from the

by astronauts during

Apollo 15 Apollo 15 (July 26August 7, 1971) was the ninth crewed mission in the Apollo program and the fourth Moon landing. It was the first List of Apollo missions#Alphabetical mission types, J mission, with a longer stay on the Moon and a greate ...

mission, has been dated at 4.08 billion years. During

Apollo 16 Apollo 16 (April 1627, 1972) was the tenth human spaceflight, crewed mission in the United States Apollo program, Apollo space program, administered by NASA, and the fifth and penultimate to Moon landing, land on the Moon. It was the second o ...

, older rocks, including Lunar sample 67215, dated at 4.46 billion years, were brought back. Some types of meteorite are older than the Earth, having formed in the early Solar System, before the planet formation process was completed. The meteorite Northwest Africa 11119 (NWA 11119) has been dated to 4.5648 ± 0.0003 billion years. Some solid inclusions within meteorites are older than the surrounding rock. Calcium-aluminium rich inclusions (CAIs) in meteorites are the oldest solids that formed in the

, so are conventionally used to set its formation date as 4567.30 ± 0.16 Myr. Pre-solar grains are even older; they formed in the

interstellar medium The interstellar medium (ISM) is the matter and radiation that exists in the outer space, space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as cosmic dust, dust and cosmic rays. It f ...

and pre-date the formation of the Solar System. Some pre-solar grains extracted from the

have been claimed to be 7 billion years old.

References

Bibliography

Zircons are Forever
* * 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. 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
2

External links

Abstract and full text of the results from O'Neil's research, published by ''Science''
{{portal bar, Earth sciences, Geology, Science Petrology Radiometric dating