Timeline of natural history

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This timeline of natural history summarizes significant geological and biological events from the formation of the Earth to the arrival of modern humans. Times are listed in millions of years, or megaanni (Ma).


Dating of the geologic record

The geologic record is the strata (layers) of rock in the planet's crust and the science of geology is much concerned with the age and origin of all rocks to determine the history and formation of Earth and to understand the forces that have acted upon it. Geologic time is the timescale used to calculate dates in the planet's geologic history from its origin (currently estimated to have been some 4,600 million years ago) to the present day.

Radiometric dating measures the steady decay of radioactive elements in an object to determine its age. It is used to calculate dates for the older part of the planet's geological record. The theory is very complicated but, in essence, the radioactive elements within an object decay to form isotopes of each chemical element. Isotopes are atoms of the element that differ in mass but share the same general properties. Geologists are most interested in the decay of isotopes carbon-14 (into nitrogen-14) and potassium-40 (into argon-40). Carbon-14 aka radiocarbon dating works for organic materials that are less than about 50,000 years old. For older periods, the potassium-argon dating process is more accurate.

Radiocarbon dating is carried out by measuring how much of the carbon-14 and nitrogen-14 isotopes are found in a material. The ratio between the two is used to estimate the material's age. Suitable materials include wood, charcoal, paper, fabrics, fossils and shells. It is assumed that rock exists in layers according to age, with older beds below later ones. This is the basis of stratigraphy.

The ages of more recent layers are calculated primarily by the study of fossils, which are remains of ancient life preserved in the rock. These occur consistently and so a theory is feasible. Most of the boundaries in recent geologic time coincide with extinctions (e.g., the dinosaurs) and with the appearances of new species (e.g., hominids).

The earliest Solar System

In the earliest Solar System history, the Sun, the planetesimals and the jovian planets were formed. The inner Solar System aggregated more slowly than the outer, so the terrestrial planets were not yet formed, including Earth and Moon.

Precambrian Supereon

Hadean Eon

Archean Eon

Eoarchean Era

Paleoarchean Era

Mesoarchean Era

Neoarchean Era

Proterozoic Eon

The Proterozoic (from c. 2500 Ma to c. 541 Ma) saw the first traces of biological activity. Fossil remains of bacteria and algae.

Paleoproterozoic Era

Siderian Period

Rhyacian Period

  • c. 2,300 Ma – Rhyacian period starts.
  • c. 2,250 Ma – Bushveld Igneous Complex forms: world's largest reserves of platinum-group metals (platinum, palladium, osmium, iridium, rhodium and ruthenium), as well as vast quantities of iron, tin, chromium, titanium and vanadium appear – formation of Transvaal Basin begins.
  • c. 2,200–1800 Ma – Continental Red Beds found, produced by iron in weathered sandstone being exposed to oxygen. Eburnean Orogeny, series of tectonic, metamorphic and plutonic events establish Eglab Shield to the north of West African Craton and Man Shield to its south – Birimian domain of West Africa established and structured.
  • c. 2,200 Ma – Iron content of ancient fossil soils shows an oxygen built up to 5–18% of current levels. [17] End of Kenoran Orogeny: invasion of Superior and Slave Provinces by basaltic dikes and sills – Wyoming and Montana arm of Superior Province experiences intrusion of 5 km thick sheet of chromite-bearing gabbroic rock as Stillwater Complex forms.
  • c. 2,100 Ma – Huronian glaciation ends. Earliest known eukaryote fossils found. Earliest multicellular organisms collectively referred to as the "Gabonionta" (Francevillian Group Fossil); Wopmay orogeny along western margin of Canadian Shield.
  • c. 2,090 Ma – Eburnean Orogeny: Eglab Shield experiences syntectonic trondhjemitic pluton intrusion of its Chegga series – most of the intrusion is in the form of a plagioclase called oligoclase.
  • 2.070 Ma – Eburnean Orogeny: asthenospheric upwelling releases large volume of post-orogenic magmas – magma events repeatedly reactivated from the Neoproterozoic to the Mesozoic.

Orosirian Period

Statherian Period

  • c. 1,800 Ma – Statherian Period starts. Supercontinent Columbia forms, one of whose fragments being Nena. Oldest ergs develop on several cratons [13] Barramundi Orogeny (c. 1.8 Gyr) influences MacArthur Basin in Northern Australia.
  • c. 1,780 Ma – Colorado Orogeny (1.78 1.65 Gyr) influences southern margin of Wyoming craton–collision of Colorado orogen and Trans-Hudson orogen with stabilized Archean craton structure
  • c. 1,770 Ma – Big Sky Orogeny (1.77 Gyr) influences southwest Montana: collision between Hearne and Wyoming cratons
  • c. 1,765 Ma – As Kimban Orogeny in Australian continent slows, Yapungku Orogeny (1.765 Gyr) begins affecting Yilgarn craton in Western Australia possible formation of Darling Fault, one of longest and most significant in Australia
  • c. 1,760 Ma – Yavapai Orogeny (1.76–1.7 Gyr) impacts mid- to south-western United States
  • c. 1,750 Ma – Gothian Orogeny (1.75–1.5 Gyr): formation of tonalitic-granodioritic plutonic rocks and calc-alkaline volcanites in the East European Craton
  • c. 1,700 Ma – Stabilization of second major continental mass, the Guiana Shield in South America
  • c. 1,680 Ma – Mangaroon Orogeny (1.68–1.62 Gyr), on the Gascoyne Complex in Western Australia: Durlacher Supersuite, granite intrusion featuring a northern (Minnie Creek) and southern belt heavily sheared orthoclase porphyroclastic granites
  • c. 1,650 Ma – Kararan Orogeny (1.65 Gyr) uplifts great mountains on the Gawler Craton in Southern Australia  formation of Gawler Range including picturesque Conical Hill Track and "Organ Pipes" waterfall

Mesoproterozoic Era

Calymmian Period

  • c. 1,600 Ma – Mesoproterozoic Era and Calymmian Period start. Platform covers expand. Major orogenic event in Australia: Isan Orogeny influences Mount Isa Block of Queensland major deposits of lead, silver, copper and zinc are laid down. Mazatzal Orogeny (to c. 1,300 Ma) influences mid- to south-western United States: Precambrian rocks of the Grand Canyon, Vishnu Schist and Grand Canyon Series, are formed establishing basement of Canyon with metamorphosed gneisses that are intruded by granites. Belt Supergroup in Montana/Idaho/BC formed in basin on edge of Laurentia.
  • c. 1,500 Ma – Supercontinent Columbia splits apart: associated with continental rifting along western margin of Laurentia, eastern India, southern Baltica, southeastern Siberia, northwestern South Africa and North China Block-formation of Ghats Province in India. First structurally complex eukaryotes (Horodyskia, colonial formamiferian?).

Ectasian Period

  • c. 1,400 Ma – Ectasian Period starts. Platform covers expand. Major increase in Stromatolite diversity with widespread blue-green algae colonies and reefs dominating tidal zones of oceans and seas
  • c. 1,300 Ma – Break-up of Columbia Supercontinent completed: widespread anorogenic magmatic activity, forming anorthosite-mangerite-charnockite-granite suites in North America, Baltica, Amazonia and North China stabilization of Amazonian Craton in South America Grenville orogeny(to c. 1,000 Ma) in North America: globally associated with assembly of Supercontinent Rodinia establishes Grenville Province in Eastern North America folded mountains from Newfoundland to North Carolina as Old Rag Mountain forms
  • c. 1,270 Ma – Emplacement of Mackenzie granite mafic dike swarm one of three dozen dike swarms, forms into Mackenzie Large Igneous Province formation of Copper Creek deposits
  • c. 1,250 Ma – Sveconorwegian Orogeny (to c. 900 Ma) begins: essentially a reworking of previously formed crust on the Baltic Shield
  • c. 1,240 Ma – Second major dike swarm, Sudbury dikes form in Northeastern Ontario around the area of the Sudbury Basin

Stenian Period

  • c. 1,200 Ma – Stenian Period starts. Red alga Bangiomorpha pubescens, earliest fossil evidence for sexually reproducing organism. [20] Meiosis and sexual reproduction are present in single-celled eukaryotes, and possibly in the common ancestor of all eukaryotes. [21] Supercontinent of Rodinia (1.2 Gyr–750 Ma) completed: consisting of North American, East European, Amazonian, West African, Eastern Antarctica, Australia and China blocks, largest global system yet formed surrounded by superocean Mirovia
  • c. 1,100 Ma – First dinoflagellate evolve; photosynthetic, some develop mixotrophic habits of ingesting prey. Thus, they become the first predators, forcing acritarchs to defensive strategies and leading to open "arms" race. Late Ruker (1.1–1 Gyr) and Nimrod Orogenies (1.1 Gyr) in Antarctica possibly begins: formation of Gamburtsev mountain range and Vostok Subglacial Highlands. Keweenawan Rift buckles in the south-central part of the North American plate leaves behind thick layers of rock that are exposed in Wisconsin, Minnesota, Iowa and Nebraska and creates rift valley where future Lake Superior develops.
  • c. 1,080 Ma – Musgrave Orogeny (c. 1.080 Gyr) forms Musgrave Block, an east–west trending belt of granulite-gneiss basement rocks voluminous Kulgera Suite of granite and Birksgate Complex solidify
  • c. 1,076 Ma – Musgrave Orogeny: Warakurna large igneous province develops intrusion of Giles Complex and Winburn Suite of granites and deposition of Bentley Supergroup (including Tollu and Smoke Hill Volcanics)
  • c. 1,010 Ma – Ourasphaira giraldae : multicellular organic-walled microfossils preserved in shale of the Grassy Bay Formation (Canadian Arctic) with fungal affinity. [22]

Neoproterozoic Era

Tonian Period

  • c. 1,000 Ma – Neoproterozoic Era and Tonian Period start. Grenville orogeny ends. First radiation of dinoflagellates and spiny acritarchs  increase in defensive systems indicate that acritarchs are responding to carnivorous habits of dinoflagellates decline in stromatolite reef populations begins. Rodinia starts to break up. First vaucherian algae. Rayner Orogeny as proto-India and Antarctica collide (to c. 900 Ma). Trace fossils of colonial Horodyskia (to c. 900 Ma): possible divergence between animal and plant kingdoms begins. Stabilization of Satpura Province in Northern India. Rayner Orogeny (1 Gyr 900 Ma) as India and Antarctica collide
  • c. 920 Ma – Edmundian Orogeny (c. 920–850 Ma) redefines Gascoyne Complex: consists of reactivation of earlier formed faults in the Gascoyne folding and faulting of overlying Edmund and Collier basins
  • c. 920 Ma – Adelaide Geosyncline laid down in central Australia essentially a rift complex, consists of thick layer of sedimentary rock and minor volcanics deposited on Easter margin limestones, shales and sandstones predominate
  • c. 900 Ma – Bitter Springs Formation of Australia: in addition to prokaryote assemblage of fossils, cherts include eukaryotes with ghostly internal structures similar to green algae first appearance of Glenobotrydion (900–720 Ma), among earliest plants on Earth
  • c. 830 Ma – Rift develops on Rodinia between continental masses of Australia, eastern Antarctica, India, Congo and Kalahari on one side and Laurentia, Baltica, Amazonia, West African and Rio de la Plata cratons on other formation of Adamastor Ocean.
  • c. 800 Ma – With free oxygen levels much higher, carbon cycle is disrupted and once again glaciation becomes severe beginning of second "snowball Earth" event
  • c. 750 Ma – First Protozoa appears: as creatures like Paramecium, Amoeba and Melanocyrillium evolve, first animal-like cells become distinctive from plants rise of herbivores (plant feeders) in the food chain. First Sponge-like animal: similar to early colonial foraminiferan Horodyskia, earliest ancestors of Sponges were colonial cells that circulated food sources using flagella to their gullet to be digested. Kaigas (c. 750 Ma): first thought o be a major glaciation of Earth, however, the Kaigas formation was later determined to be non-glacial. [23]

Cryogenian Period

  • c. 720 Ma – Cryogenian Period starts, during which Earth freezes over (Snowball Earth or Slushball Earth) at least 3 times. The Sturtian glaciation continues the process begun during Kaigas great ice sheets cover most of the planet stunting evolutionary development of animal and plant life survival based on small pockets of heat under the ice.
  • c. 700 Ma – Fossils of testate Amoeba first appear: first complex metazoans leave unconfirmed biomarkers they introduce new complex body plan architecture which allows for development of complex internal and external structures. Worm trail impressions in China: because putative "burrows" under stromatolite mounds are of uneven width and tapering makes biological origin difficult to defend structures imply simple feeding behaviours. Rifting of Rodinia is completed: formation of new superocean of Panthalassa as previous Mirovia ocean bed closes Mozambique mobile belt develops as a suture between plates on Congo-Tanzania craton
  • c. 660 Ma – As Sturtian glaciers retreat, Cadomian orogeny (660–540 Ma) begins on north coast of Armorica: involving one or more collisions of island arcs on margin of future Gondwana, terranes of Avalonia, Armorica and Iberia are laid down
  • c. 650 Ma – First Demosponges appear: form first skeletons of spicules made from protein spongin and silica brightly coloured these colonial creatures filter feed since they lack nervous, digestive or circulatory systems and reproduce both sexually and asexually
  • c. 650 Ma – Final period of worldwide glaciation, Marinoan (650–635 Ma) begins: most significant "snowball Earth" event, global in scope and longer evidence from Diamictite deposits in South Australia laid down on Adelaide Geosyncline

Ediacaran Period

  • c. 635 Ma – Ediacaran period begins. End of Marinoan Glaciation: last major "snowball Earth" event as future ice ages will feature less overall ice coverage of the planet
  • c. 633 Ma – Beardmore Orogeny (to c. 620 Ma) in Antarctica: reflection of final break-up of Rodinia as pieces of the supercontinent begin moving together again to form Pannotia
  • c. 620 Ma – Timanide Orogeny (to c. 550 Ma) affects northern Baltic Shield: gneiss province divided into several north–south trending segments experiences numerous metasedimentary and metavolcanic deposits last major orogenic event of Precambrian
  • c. 600 Ma – Pan-African Orogeny begins: Arabian-Nubian Shield formed between plates separating supercontinent fragments Gondwana and Pannotia  Supercontinent Pannotia (to c. 500 Ma) completed, bordered by Iapetus and Panthalassa oceans. Accumulation of atmospheric oxygen allows for the formation of ozone layer: prior to this, land-based life would probably have required other chemicals to attenuate ultraviolet radiation enough to permit colonization of the land
  • c. 575 Ma – First Ediacaran-type fossils.
  • c. 565 Ma  Charnia, a frond-like organism, first evolves.
  • c. 560 Ma – Trace fossils, e.g., worm burrows, and small bilaterally symmetrical animals. Earliest arthropods. Earliest fungi.
  • c. 558 Ma  Dickinsonia, a large slow moving disc-like creature, first appears the discovery of fat molecules in its tissues make it the first confirmed true metazoan animal of the fossil record.
  • c. 555 Ma – The first possible mollusk Kimberella appears.
  • c. 550 Ma – First possible comb-jellies, sponges, corals, and anemones.
  • c. 550 Ma  Uluru or Ayers Rock begins forming during the Petermann Orogeny in Australia
  • c. 544 Ma – The small shelly fauna first appears.

Phanerozoic Eon

Paleozoic Era

Cambrian Period

Ordovician Period

Silurian Period

Devonian Period

  • c. 419.2± 3.2 Ma – Beginning of the Devonian and end of the Silurian Period. First insects.
  • c. 419 Ma – Old Red Sandstone sediments begin being laid in the North Atlantic region including Britain, Ireland, Norway and in the west along the northeastern seaboard of North America. It also extends northwards into Greenland and Svalbard.
  • c. 415 Ma – Cephalaspis, an iconic member of the Osteostraci, appears, the most advanced of the jawless fish. Its boney armor serves as protection against the successful radiation of Placoderms and as a way to live in calcium-poor fresh water environments.
  • c. 395 Ma – First of many modern groups, including tetrapods.
  • c. 375 Ma – Acadian Orogeny begins influencing mountain building along the Atlantic seaboard of North America.
  • c. 370 Ma – Cladoselache, an early shark, first appears.
  • c. 363 Ma – Vascular plants begin to create the earliest stable soils on land.
  • c. 360 Ma – First crabs and ferns. The large predatory lobe-finned fish Hyneria evolves.
  • c. 350 Ma – First large sharks, ratfish and hagfish.

Carboniferous Period

  • c. 358.9± 0.4 Ma – Beginning of the Carboniferous and the end of Devonian Period. Amphibians diversify.
  • c. 345 Ma – Agaricocrinus americanus a representative of the Crinoids appears as part of a successful radiation of the echinoderms.
  • c. 330 Ma – First amniotes evolve.
  • c. 320 Ma – First synapsids evolve.
  • c. 318 Ma – First beetles.
  • c. 315 Ma – The evolution of the first reptiles.
  • c. 312 Ma – Hylonomus makes first appearance, one of the oldest reptiles found in the fossil record.
  • c. 306 Ma – Diplocaulus evolves in the swamps with an unusual boomerang-like skull.
  • c. 305 Ma – First diapsids evolve; Meganeura a giant dragonfly dominates the skies.
  • c. 300 Ma – Last great period of mountain building episodes in Europe and North America in response to the final suturing together of the supercontinent Pangaea – the Ural mountains are uplifted

Permian Period

Mesozoic Era

Triassic Period

Jurassic Period

Cretaceous Period

Cenozoic Era

Paleogene Period

Neogene Period

Quaternary Period

Etymology of period names

Period Started Root wordMeaningReason for name
Siderian c. 2500 Ma Greek siderosironref. the banded iron formations
Rhyacian c. 2300 MaGk. rhyax lava flowmuch lava flowed
Orosirian c. 2050 MaGk. oroseiramountain rangemuch orogeny in this period's latter half
Statherian c. 1800 MaGk. statherossteadycontinents became stable cratons
Calymmian c. 1600 MaGk. calymmacover platform covers developed or expanded
Ectasian c. 1400 MaGk. ectasisextension platform covers expanded
Stenian c. 1200 MaGk. stenosnarrowmuch orogeny, which survives as narrow metamorphic belts
Tonian c. 1000 MaGk. tonosstretchThe continental crust stretched as Rodinia broke up
Cryogenian c. 720 MaGk. cryogenicos cold-makingIn this period all the Earth froze over
Ediacaran c. 635 Ma Ediacara Hills stony groundplace in Australia where the Ediacaran biota fossils were found
Cambrian c. 538.8 Ma Latin Cambria Wales ref. to the place in Great Britain where Cambrian rocks are best exposed
Ordovician c. 485.4 Ma Celtic Ordovices Tribe in north Wales, where the rocks were first identified
Silurian c. 443.8 MaCtc. Silures Tribe in south Wales, where the rocks were first identified
Devonian c. 419.2 Ma Devon County in England in which rocks from this period were first identified
Carboniferous c. 358.9 MaLt. carbocoalGlobal coal beds were laid in this period
Permian c. 298.9 Ma Perm Krai Region in Russia where rocks from this period were first identified
Triassic c. 251.902 MaLt. triastriadIn Germany this period forms three distinct layers
Jurassic c. 201.4 Ma Jura Mountains Mountain range in the Alps in which rocks from this period were first identified
Cretaceous c. 145 MaLt. cretachalkMore chalk formed in this period than any other
Paleogene c. 66 MaGk. palaiogenos"ancient born"
Neogene c. 23.03 MaGk. neogenos"new born"
Quaternary c. 2.58 MaLt. quaternarius"fourth"This was initially deemed the "fourth" period after the now-obsolete "primary", "secondary" and "tertiary" periods.

Visual summary

Nature timespiral horizontal layout white background.png
The history of nature from the Big Bang to the present day with notable events annotated. Every billion years (Ga) is represented by 90 degrees of rotation of the spiral. The last 500 million years are represented in a 90-degree stretch for more detail on our recent history.

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.

<span class="mw-page-title-main">Proterozoic</span> Third eon of the geologic timescale, last eon of the Precambrian Supereon

The Proterozoic is the third of the four geologic eons of Earth's history, spanning the time interval from 2500 to 538.8 Mya, the longest eon of the Earth's geologic time scale. It is preceded by the Archean and followed by the Phanerozoic, and is the most recent part of the Precambrian "supereon".

<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">Paleoarchean</span> Second era of the Archean Eon

The Paleoarchean, also spelled Palaeoarchaean, is a geologic era within the Archean Eon. The name derives from Greek "Palaios" ancient. It spans the period of time 3,600 to 3,200 million years ago. The era is defined chronometrically and is not referenced to a specific level of a rock section on Earth. The earliest confirmed evidence of life comes from this era, and Vaalbara, one of Earth's earliest supercontinents, may have formed during this era.

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

The Yilgarn Craton is a large craton that constitutes the bulk 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">Geology of Australia</span> Overview of the geology of Australia

The geology of Australia includes virtually all known rock types, spanning a geological time period of over 3.8 billion years, including some of the oldest rocks on earth. Australia is a continent situated on the Indo-Australian Plate.

<span class="mw-page-title-main">Oldest dated rocks</span> Includes rocks over 4 billion years old from the Hadean Eon

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. 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.

The Pan-African orogeny was a series of major Neoproterozoic orogenic events which related to the formation of the supercontinents Gondwana and Pannotia about 600 million years ago. This orogeny is also known as the Pan-Gondwanan or Saldanian Orogeny. The Pan-African orogeny and the Grenville orogeny are the largest known systems of orogenies on Earth. The sum of the continental crust formed in the Pan-African orogeny and the Grenville orogeny makes the Neoproterozoic the period of Earth's history that has produced most continental crust.

<span class="mw-page-title-main">Vaalbara</span> Archaean supercontinent from about 3.6 to 2.7 billion years ago

Vaalbara is a hypothetical Archean supercontinent consisting of the Kaapvaal Craton and the Pilbara Craton. E. S. Cheney derived the name from the last four letters of each craton's name. The two cratons consist of crust dating from 2.7 to 3.6 Gya, which would make Vaalbara one of Earth's earliest supercontinents.

<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.

<span class="mw-page-title-main">Laurentia</span> A large continental craton that forms the ancient geological core of the North American continent

Laurentia or the North American Craton is a large continental craton that forms the ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, although originally it also included the cratonic areas of Greenland and also the northwestern part of Scotland, known as the Hebridean Terrane. During other times in its past, Laurentia has been part of larger continents and supercontinents and itself consists of many smaller terranes assembled on a network of Early Proterozoic orogenic belts. Small microcontinents and oceanic islands collided with and sutured onto the ever-growing Laurentia, and together formed the stable Precambrian craton seen today.

The West African Craton (WAC) is one of the five cratons of the Precambrian basement rock of Africa that make up the African Plate, the others being the Kalahari craton, Congo craton, Saharan Metacraton and Tanzania Craton. Cratons themselves are tectonically inactive, but can occur near active margins, with the WAC extending across 14 countries in Western Africa, coming together in the late Precambrian and early Palaeozoic eras to form the African continent. It consists of two Archean centers juxtaposed against multiple Paleoproterozoic domains made of greenstone belts, sedimentary basins, regional granitoid-tonalite-trondhjemite-granodiorite (TTG) plutons, and large shear zones. The craton is overlain by Neoproterozoic and younger sedimentary basins. The boundaries of the WAC are predominantly defined by a combination of geophysics and surface geology, with additional constraints by the geochemistry of the region. At one time, volcanic action around the rim of the craton may have contributed to a major global warming event.

A paleocontinent or palaeocontinent is a distinct area of continental crust that existed as a major landmass in the geological past. There have been many different landmasses throughout Earth's time. They range in sizes, some are just a collection of small microcontinents while others are large conglomerates of crust. As time progresses and sea levels rise and fall more crust can be exposed making way for larger landmasses. The continents of the past shaped the evolution of organisms on Earth and contributed to the climate of the globe as well. As landmasses break apart, species are separated and those that were once the same now have evolved to their new climate. The constant movement of these landmasses greatly determines the distribution of organisms on Earth's surface. This is evident with how similar fossils are found on completely separate continents. Also, as continents move, mountain building events (orogenies) occur, causing a shift in the global climate as new rock is exposed and then there is more exposed rock at higher elevations. This causes glacial ice expansion and an overall cooler global climate. The movement of the continents greatly affects the overall dispersal of organisms throughout the world and the trend in climate throughout Earth's history. Examples include Laurentia, Baltica and Avalonia, which collided together during the Caledonian orogeny to form the Old Red Sandstone paleocontinent of Laurussia. Another example includes a collision that occurred during the late Pennsylvanian and early Permian time when there was a collision between the two continents of Tarimsky and Kirghiz-Kazakh. This collision was caused because of their askew convergence when the paleoceanic basin closed.

<span class="mw-page-title-main">Algoman orogeny</span> Late Archaean episode of mountain building in what is now North America

The Algoman orogeny, known as the Kenoran orogeny in Canada, was an episode of mountain-building (orogeny) during the Late Archean Eon that involved repeated episodes of continental collisions, compressions and subductions. The Superior province and the Minnesota River Valley terrane collided about 2,700 to 2,500 million years ago. The collision folded the Earth's crust and produced enough heat and pressure to metamorphose the rock. Blocks were added to the Superior province along a 1,200 km (750 mi) boundary that stretches from present-day eastern South Dakota into the Lake Huron area. The Algoman orogeny brought the Archean Eon to a close, about 2,500 million years ago; it lasted less than 100 million years and marks a major change in the development of the Earth's crust.

<span class="mw-page-title-main">East Antarctic Shield</span> Cratonic rock body which makes up most of the continent Antarctica

The East Antarctic Shield or Craton is a cratonic rock body that covers 10.2 million square kilometers or roughly 73% of the continent of Antarctica. The shield is almost entirely buried by the East Antarctic Ice Sheet that has an average thickness of 2200 meters but reaches up to 4700 meters in some locations. East Antarctica is separated from West Antarctica by the 100–300 kilometer wide Transantarctic Mountains, which span nearly 3,500 kilometers from the Weddell Sea to the Ross Sea. The East Antarctic Shield is then divided into an extensive central craton that occupies most of the continental interior and various other marginal cratons that are exposed along the coast.

<span class="mw-page-title-main">Tectonic evolution of the Aravalli Mountains</span> Overview article

The Aravalli Mountain Range is a northeast-southwest trending orogenic belt in the northwest part of India and is part of the Indian Shield that was formed from a series of cratonic collisions. The Aravalli Mountains consist of the Aravalli and Delhi fold belts, and are collectively known as the Aravalli-Delhi orogenic belt. The whole mountain range is about 700 km long. Unlike the much younger Himalayan section nearby, the Aravalli Mountains are believed much older and can be traced back to the Proterozoic Eon. They are arguably the oldest geological feature on Earth. The collision between the Bundelkhand craton and the Marwar craton is believed to be the primary mechanism for the development of the mountain range.

<span class="mw-page-title-main">Geology of the Democratic Republic of the Congo</span>

The geology of the Democratic Republic of the Congo is extremely old, on the order of several billion years for many rocks. The country spans the Congo Craton: a stable section of ancient continental crust, deformed and influenced by several different mountain building orogeny events, sedimentation, volcanism and the geologically recent effects of the East Africa Rift System in the east. The country's complicated tectonic past have yielded large deposits of gold, diamonds, coltan and other valuable minerals.

The Superior Craton is a stable crustal block covering Quebec, Ontario, and southeast Manitoba in Canada, and northern Minnesota in the United States. It is the biggest craton among those formed during the Archean period. A craton is a large part of the Earth's crust that has been stable and subjected to very little geological changes over a long time. The size of Superior Craton is about 1,572,000 km2. The craton underwent a series of events from 4.3 to 2.57 Ga. These events included the growth, drifting and deformation of both oceanic and continental crusts.


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