Oldest dated rocks

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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. 4,030,000,000 Years Acasta Gneiss.jpg
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.
The Moon rock "Big Bertha", collected on the 1971 Apollo 14 mission, contains an Earth meteorite that is 4 billion years old. Big Bertha sample 14321.jpg
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 Earth, as an aggregate of minerals that have not been subsequently broken down by erosion or melted, are more than 4 billion years old, formed during the Hadean Eon of Earth's geological history, and mark the start of the Archean Eon, which is defined to start with the formation of the oldest intact rocks on Earth. Meteorites that were formed in other planetary systems can pre-date Earth. Particles from the Murchison meteorite were dated in January 2020 to be 7 billion years old. [1]

Contents

Archean rocks are exposed on Earth's surface in very few places, such as in the geologic shields of Canada, Australia, and Africa. The ages of these 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 Acasta Gneiss of the Slave craton in northwestern Canada. [2] Researchers at McGill University 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, in northern Quebec; [3] the true age of these samples is still under debate, and they may actually be closer to 3.8 billion years old. [4] Older than these rocks are crystals of the mineral zircon, 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. Apollo 14 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, contained "a bit of Earth from about 4 billion years ago". The rock fragment contained quartz, feldspar, and zircon, all common on Earth, but highly uncommon on the Moon. [5] In January 2020, astronomers reported that the oldest material on Earth found so far are 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. [6] [7]

Oldest rocks by category

Oldest terrestrial material

The oldest material of terrestrial origin that has been dated is a zircon mineral of 4.404 ±0.008 Ga enclosed in a metamorphosed sandstone conglomerate in the Jack Hills of the Narryer Gneiss Terrane of Western Australia. [8] The 4.404 ±0.008 Ga zircon is a slight outlier, with the oldest consistently dated zircon falling closer to 4.35 Ga. [8] 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. [9]

The discovery of the oldest known Earth rock, found on the Moon, was reported in January 2019 by NASA scientists. Apollo 14 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 quartz, feldspar, and zircon, all common on Earth, but highly uncommon on the Moon. [5]

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 Acasta Gneiss (on the Slave Craton). The difficulty in assigning the title to one particular block of gneiss is that the gneisses are all extremely deformed, and the oldest rock may be represented by only one streak of minerals in a mylonite, 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 are 3.5 Ga old. [10]

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

Fragment of Acasta Gneiss Acasta Gneiss fragment.JPG
Fragment of Acasta Gneiss

The Acasta Gneiss in the Canadian Shield in the Northwest Territories, Canada is composed of the Archaean igneous and gneissic cores of ancient mountain chains that have been exposed in a glacial peneplain. Analyses of zircons from a felsic orthogneiss with presumed granitic protolith returned an age of 4.031 ±0.003 Ga. [2]

On September 25, 2008, researchers from McGill University, 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. [11] [12] [13] [14] 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. [4]

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 rare-earth elements) record more recent hydrothermal alteration of the zircons rather than the composition of the magma at the time of their original crystallization.[ citation needed ] 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. [15]

The main mass of NWA 11119 found in Mauritania in December 2016. It is the first, and oldest, silica-rich (andesitic to dacitic) porphyritic extrusive crustal rock with an Al-Mg age of 4564.8 (+- 0.3) Ma. Main mass of the Northwest Africa (NWA) 11119 meteorite.png
The main mass of NWA 11119 found in Mauritania in December 2016. It is the first, and oldest, silica-rich (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 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). [6] [7]

One of the oldest Martian meteorites found on Earth, Allan Hills 84001, discovered in the Allan Hills of Antarctica, has been reported to have crystallized from molten rock 4.091 billion years ago. [16]

The Genesis Rock (Lunar sample 15415), obtained from the Moon by astronauts during Apollo 15 mission, has been dated at 4.08 billion years. [17] During Apollo 16, older rocks, including Lunar sample 67215, dated at 4.46 billion years, were brought back. [18]

A volcanic meteorite Northwest Africa (NWA) 11119 found in Mauritania in December 2016 has been dated to 4.5648 ± 0.0003 billion years. [19]

See also

Related Research Articles

The Precambrian is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic Eon, which is named after Cambria, the Latinised name for Wales, where rocks from this age were first studied. The Precambrian accounts for 88% of the Earth's geologic time.

The Hadean is the first and oldest of the four known geologic eons of Earth's history, starting with the planet's formation about 4.54 Bya, now defined as Mya set by the age of the oldest solid material in the Solar System found in some meteorites about 4.567 billion years old. The supposed interplanetary collision that created the Moon occurred early in this eon. The Hadean ended 4.031 billion years ago and was succeeded by the Archean eon, with the Late Heavy Bombardment hypothesized to have occurred at the Hadean-Archean boundary.

<span class="mw-page-title-main">Kenorland</span> Hypothetical Neoarchaean supercontinent from about 2.8 billion years ago

Kenorland was one of the earliest known supercontinents on Earth. It is thought to have formed during the Neoarchaean Era c. 2.72 billion years ago by the accretion of Neoarchaean cratons and the formation of new continental crust. It comprised what later became Laurentia, Baltica, Western Australia and Kalaharia.

<span class="mw-page-title-main">Eoarchean</span> First era of the Archean Eon

The Eoarchean is the first era of the Archean Eon of the geologic record. It spans 431 million years, from the end of the Hadean Eon 4031 Mya to the start of the Paleoarchean Era 3600 Mya. The beginnings of life on Earth have been dated to this era and evidence of archaea and cyanobacteria date to 3500 Mya, comparatively shortly after the Eoarchean. At that time, the atmosphere was without oxygen and the pressure values ranged from 10 to 100 bar.

<span class="mw-page-title-main">Acasta Gneiss</span> Metamorphic rock unit in Canada

The Acasta Gneiss Complex, also called the Acasta Gneiss, is a body of felsic to ultramafic Archean basement rocks, gneisses, that form the northwestern edge of the Slave Craton in the Northwest Territories, Canada, about 300 km (190 mi) north of Yellowknife, Canada. This geologic complex consists largely of tonalitic and granodioritic gneisses and lesser amounts of mafic and ultramafic gneisses. It underlies and is largely concealed by thin, patchy cover of Quaternary glacial sediments over an area of about 13,000 km2 (5,000 sq mi). The Acasta Gneiss Complex contains fragments of the oldest known crust and record of more than a billion years of magmatism and metamorphism. The Acasta Gneiss Complex is exposed in a set of anticlinoriums within the foreland fold and thrust belt of the Paleoproterozoic Wopmay Orogen.

<span class="mw-page-title-main">Jack Hills</span> Range of hills in Western Australia

The Jack Hills are a range of hills in Mid West Western Australia. They are best known as the source of the oldest material of terrestrial origin found to date: Hadean zircons that formed around 4.404 billion years ago. These zircons have enabled deeper research into the conditions on Earth in the Hadean eon. In 2015, "remains of biotic life" were found in 4.1 billion-year-old rocks there. According to one of the researchers, "If life arose relatively quickly on Earth ...then it could be common in the universe."

<span class="mw-page-title-main">Narryer Gneiss Terrane</span> Geological complex of ancient rocks in Western Australia

The Narryer Gneiss Terrane is a geological complex in Western Australia that is composed of a tectonically interleaved and polydeformed mixture of granite, mafic intrusions and metasedimentary rocks in excess of 3.3 billion years old, with the majority of the Narryer Gneiss Terrane in excess of 3.6 billion years old. The rocks have experienced multiple metamorphic events at amphibolite or granulite conditions, resulting in often complete destruction of original igneous or sedimentary (protolith) textures. Importantly, it contains the oldest known samples of the Earth's crust: samples of zircon from the Jack Hills portion of the Narryer Gneiss have been radiometrically dated at 4.4 billion years old, although the majority of zircon crystals are about 3.6-3.8 billion years old.

<span class="mw-page-title-main">Yilgarn Craton</span> Large craton in Western Australia

The Yilgarn Craton is a large craton that constitutes a major part of the Western Australian land mass. It is bounded by a mixture of sedimentary basins and Proterozoic fold and thrust belts. Zircon grains in the Jack Hills, Narryer Terrane have been dated at ~4.27 Ga, with one detrital zircon dated as old as 4.4 Ga.

<span class="mw-page-title-main">Isua Greenstone Belt</span> Archean greenstone belt in southwestern Greenland

The Isua Greenstone Belt is an Archean greenstone belt in southwestern Greenland, aged between 3.7 and 3.8 billion years. The belt contains variably metamorphosed mafic volcanic and sedimentary rocks, and is the largest exposure of Eoarchaean supracrustal rocks on Earth. Due to its age and low metamorphic grade relative to many Eoarchaean rocks, the Isua Greenstone Belt has become a focus for investigations on the emergence of life and the style of tectonics that operated on the early Earth.

Early Earth is loosely defined as encompassing Earth in its first one billion years, or gigayear (Ga, 109 y), from its initial formation in the young Solar System at about 4.55 Ga to some time in the Archean eon in approximately 3.5 Ga. On the geologic time scale, this comprises all of the Hadean eon, starting with the formation of the Earth about 4.6 billion years ago, and the Eoarchean, starting 4 billion years ago, and part of the Paleoarchean era, starting 3.6 billion years ago, of the Archean eon.

<span class="mw-page-title-main">Slave Craton</span> Archaean craton in the north-western Canadian Shield, in Northwest Territories and Nunavut

The Slave Craton is an Archaean craton in the north-western Canadian Shield, in Northwest Territories and Nunavut. The Slave Craton includes the 4.03 Ga-old Acasta Gneiss which is one of the oldest dated rocks on Earth. Covering about 300,000 km2 (120,000 sq mi), it is a relatively small but well-exposed craton dominated by ~2.73–2.63 Ga greenstones and turbidite sequences and ~2.72–2.58 Ga plutonic rocks, with large parts of the craton underlain by older gneiss and granitoid units. The Slave Craton is one of the blocks that compose the Precambrian core of North America, also known as the palaeocontinent Laurentia.

<span class="mw-page-title-main">Kaapvaal Craton</span> Archaean craton, possibly part of the Vaalbara supercontinent

The Kaapvaal Craton, along with the Pilbara Craton of Western Australia, are the only remaining areas of pristine 3.6–2.5 Ga crust on Earth. Similarities of rock records from both these cratons, especially of the overlying late Archean sequences, suggest that they were once part of the Vaalbara supercontinent.

Supracrustal rocks are rocks that were deposited on the existing basement rocks of the crust, hence the name. They may be further metamorphosed from both sedimentary and volcanic rocks.

<span class="mw-page-title-main">Nuvvuagittuq Greenstone Belt</span> Geologic sequence in Quebec, Canada

The Nuvvuagittuq Greenstone Belt is a sequence of metamorphosed mafic to ultramafic volcanic and associated sedimentary rocks located on the eastern shore of Hudson Bay, 40 km southeast of Inukjuak, Quebec. These rocks have undergone extensive metamorphism, and represent some of the oldest surface rocks on Earth.

<span class="mw-page-title-main">Late Heavy Bombardment</span> Hypothesized astronomical event

The Late Heavy Bombardment (LHB), or lunar cataclysm, is a hypothesized astronomical event thought to have occurred approximately 4.1 to 3.8 billion years (Ga) ago, at a time corresponding to the Neohadean and Eoarchean eras on Earth. According to the hypothesis, during this interval, a disproportionately large number of asteroids and comets collided into the terrestrial planets and their natural satellites of the inner Solar System, including Mercury, Venus, Earth and Mars. These came from both post-accretion and planetary instability-driven populations of impactors. Although it used to be widely accepted, it remained difficult to provide an overwhelming amount of evidence for the hypothesis. However, recent re-appraisal of the cosmo-chemical constraints indicates that there was likely no late spike in the bombardment rate.

<span class="mw-page-title-main">Eoarchean geology</span> Study of the oldest crustal fragments on Earth

Eoarchean geology is the study of the oldest preserved crustal fragments of Earth during the Eoarchean era from 4.031 to 3.6 billion years ago. Major well-preserved rock units dated Eoarchean are known from three localities, the Isua Greenstone Belt in Southwest Greenland, the Acasta Gneiss in the Slave Craton in Canada, and the Nuvvuagittuq Greenstone Belt in the eastern coast of Hudson Bay in Quebec. From the dating of rocks in these three regions scientists suggest that plate tectonics could go back as early as Eoarchean.

The geology of Central African Republic (CAR) is part of the broader geology of Africa. CAR occupies a swath of ancient rocks, dating back billions of years that record significant aspects of Earth history and yield minerals vital to the country's small economy.

<span class="mw-page-title-main">Hadean zircon</span> Oldest-surviving crustal material from the Earths earliest geological time period

Hadean zircon is the oldest-surviving crustal material from the Earth's earliest geological time period, the Hadean eon, about 4 billion years ago. Zircon is a mineral that is commonly used for radiometric dating because it is highly resistant to chemical changes and appears in the form of small crystals or grains in most igneous and metamorphic host rocks.

<span class="mw-page-title-main">Eastern Block of the North China Craton</span>

The Eastern Block of the North China Craton is one of the Earth's oldest pieces of continent. It is separated from the Western Block by the Trans-North China Orogen. It is situated in northeastern China and North Korea. The Block contains rock exposures older than 2.5 billion years. It serves as an ideal place to study how the crust was formed in the past and the related tectonic settings.

<span class="mw-page-title-main">Dharwar Craton</span> Part of the Indian Shield in south India

The Dharwar Craton is an Archean continental crust craton formed between 3.6-2.5 billion years ago (Ga), which is located in southern India and considered as the oldest part of the Indian peninsula.

References

  1. ↑ Lyons, Suzannah (13 January 2020). "Grains of stardust found in meteorite that landed in Victoria". ABC News (Australia) - Science.
  2. 1 2 Bowring, Samuel A.; Williams, Ian S. (1999). "Priscoan (4.00–4.03 Ga) orthogneisses from northwestern Canada". Contributions to Mineralogy and Petrology. 134 (1): 3. Bibcode:1999CoMP..134....3B. doi:10.1007/s004100050465. S2CID   128376754.
  3. ↑ Thompson, Andrea (25 September 2008). "Oldest Rocks on Earth Found". Live Science.
  4. 1 2 Discovery of world's oldest rocks challenged
  5. 1 2 Universities Space Research Association (USRA) (24 January 2019). "Earth's Oldest Rock Found on the Moon". NASA . Retrieved 25 January 2019.
  6. 1 2 Weisberger, Mindy (13 January 2020). "7 Billion-Year-Old Stardust Is Oldest Material Found on Earth - Some of these ancient grains are billions of years older than our sun". Live Science . Retrieved 13 January 2020.
  7. 1 2 Heck, Philipp R.; et al. (13 January 2020). "Lifetimes of interstellar dust from cosmic ray exposure ages of presolar silicon carbide". Proceedings of the National Academy of Sciences of the United States of America . 117 (4): 1884–1889. Bibcode:2020PNAS..117.1884H. doi: 10.1073/pnas.1904573117 . PMC   6995017 . PMID   31932423.
  8. 1 2 Wilde, Simon A.; Valley, John W.; Peck, William H.; Graham, Colin M. (2001). "Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago (letter)" (PDF). Nature. 409 (6817): 175–178. doi:10.1038/35051550. ISSN   0028-0836. PMID   11196637. S2CID   4319774. Archived from the original on 1 September 2006. Retrieved 20 December 2006.{{cite journal}}: CS1 maint: bot: original URL status unknown (link)
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  10. ↑ Mutanen, Tapani; Huhma, Hannu (2003). "The 3.5 Ga Siurua trondhjemite gneiss in the Archaean Pudasjärvi Granulite Belt, northern Finland" (PDF). Bulletin of the Geological Society of Finland. 75 (1–2): 51–68. doi:10.17741/bgsf/75.1-2.004.
  11. ↑ O'Neil, J; Carlson, Rw; Francis, D; Stevenson, Rk (Sep 2008). "Neodymium-142 evidence for Hadean mafic crust". Science. 321 (5897): 1828–31. Bibcode:2008Sci...321.1828O. doi:10.1126/science.1161925. PMID   18818357. S2CID   206514655.
  12. ↑ McGill University press release Closed Access logo transparent.svg
  13. ↑ Oldest rocks on Earth found
  14. ↑ http://www.sciencemag.org/cgi/reprint/321/5897/1828.pdf [ permanent dead link ]
  15. ↑ Newswise: Ancient Mineral Shows Early Earth Climate Tough on Continents. Retrieved June 15, 2008.
  16. ↑ Lapen, T. J.; et al. (2010). "A Younger Age for ALH84001 and Its Geochemical Link to Shergottite Sources in Mars". Science . 328 (5976): 347–351. Bibcode:2010Sci...328..347L. doi:10.1126/science.1185395. PMID   20395507. S2CID   17601709.
  17. ↑ Meyer, C. (2011). "Lunar Sample Compendium - 15415 Ferroan Anorthosite" (PDF). NASA . Retrieved July 24, 2017.
  18. ↑ Norman, Marc D.; Borg, Lars E.; Nyquist, Lawrence E.; Bogard, Donald D. (2003). "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". Meteoritics & Planetary Science. 38 (4). Wiley: 645–661. Bibcode:2003M&PS...38..645N. doi: 10.1111/j.1945-5100.2003.tb00031.x . ISSN   1086-9379. Summary
  19. ↑ Srinivasan, Poorna; Dunlap, Daniel R; Agee, Carl B; Wadhwa, Meenakshi; Coleff, Daniel; Ziegler, Karen; Zeigler, Ryan; McCubbin, Francis M. (2 August 2018). "Silica-rich volcanism in the early solar system dated at 4.565 Ga". Nature Communications. 9 (1): 3036. Bibcode:2018NatCo...9.3036S. doi:10.1038/s41467-018-05501-0. PMC   6072707 . PMID   30072693. Open Access logo PLoS transparent.svg

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