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 akaradiocarbon 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).
In the earliest Solar System history, the Sun, the planetesimals and the giant 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.
c. 4,570 Ma – A supernova explosion (known as the primal supernova) seeds our galactic neighborhood with heavy elements that will be incorporated into the Earth, and results in a shock wave in a dense region of the Milky Way galaxy. The Ca-Al-rich inclusions, which formed 2 million years before the chondrules,[1] are a key signature of a supernova explosion.
c. 4,566 ±2 Ma – A protoplanetary disc (from which Earth eventually forms) emerges around the young Sun, which is in its T Tauri stage.
c. 4,560–4,550 Ma – Proto-Earth forms at the outer (cooler) edge of the habitable zone of the Solar System. At this stage the solar constant of the Sun was only about 73% of its current value, but liquid water may have existed on the surface of the Proto-Earth, probably due to the greenhouse warming of high levels of methane and carbon dioxide present in the atmosphere. Early bombardment phase begins: because the solar neighbourhood is rife with large planetoids and debris, Earth experiences a number of giant impacts that help to increase its overall size.
c. 4,533 Ma – The Precambrian (to c. 539 Ma[3]), now termed a "supereon" but formerly an era, is split into three geological time intervals called eons: Hadean, Archaean and Proterozoic. The latter two are sub-divided into several eras as currently defined. In total, the Precambrian comprises some 85% of geological time from the formation of Earth to the time when creatures first developed exoskeletons (i.e., hard outer parts) and thereby left abundant fossil remains.
c. 4,533 Ma – Hadean Eon, Precambrian Supereon and unofficial Cryptic era start as the Earth–Moon system forms, possibly as a result of a glancing collision between proto-Earth and the hypothetical protoplanetTheia (the Earth was considerably smaller than now, before this impact). This impact vaporized a large amount of the crust, and sent material into orbit around Earth, which lingered as rings, similar to those of Saturn, for a few million years, until they coalesced to become the Moon. The Moon geology pre-Nectarian period starts. Earth was covered by a magmatic ocean 200 kilometres (120 mi) deep resulting from the impact energy from this and other planetesimals during the early bombardment phase, and energy released by the planetary core forming. Outgassing from crustal rocks gives Earth a reducing atmosphere of methane, nitrogen, hydrogen, ammonia, and water vapour, with lesser amounts of hydrogen sulfide, carbon monoxide, then carbon dioxide. With further full outgassing over 1000–1500 K, nitrogen and ammonia become lesser constituents, and comparable amounts of methane, carbon monoxide, carbon dioxide, water vapour, and hydrogen are released.
c. 4,500 Ma – Sun enters main sequence: a solar wind sweeps the Earth-Moon system clear of debris (mainly dust and gas). End of the Early Bombardment Phase. Basin Groups Era begins on Earth.
c. 4,450 Ma – 100 million years after the Moon formed, the first lunar crust, formed of lunar anorthosite, differentiates from lower magmas. The earliest Earth crust probably forms similarly out of similar material. On Earth the pluvial period starts, in which the Earth's crust cools enough to let oceans form.
c. 4,031 Ma – Archean Eon and Eoarchean Era start. Possible first appearance of plate tectonic activity in the Earth's crust as plate structures may have begun appearing. Possible beginning of Napier Mountains Orogeny forces of faulting and folding create first metamorphic rocks. Origins of life.
c. 3,800 Ma – Oldest banded iron formations found.[9] First complete continental masses or cratons, formed of granite blocks, appear on Earth. Occurrence of initial felsic igneous activity on eastern edge of Antarctic craton as first great continental mass begins to coalesce. East European Craton begins to form – first rocks of the Ukrainian Shield and Voronezh Massif are laid down
c. 3,600 Ma – Paleoarchean Era starts. Possible assembly of the Vaalbarasupercontinent; oldest cratons on Earth (such as the Canadian Shield, East European Craton and Kaapval) begin growing as a result of crustal disturbances along continents coalescing into Vaalbara – Pilbara Craton stabilizes. Formation of Barberton greenstone belt: Makhonjwa Mountains uplifts on the eastern edge of Kaapval craton, oldest mountains in Africa – area called the "genesis of life" for exceptional preservation of fossils. Narryer Gneiss Terrane stabilizes: these gneisses become the "bedrock" for the formation of the Yilgarn Craton in Australia – noted for the survival of the Jack Hills where the oldest mineral, a zircon was uncovered.
c. 3,460 Ma – Fossils of bacteriainchert.[citation needed]Zimbabwe Craton stabilizes from the suture of two smaller crustal blocks, the Tokwe Segment to the south and the Rhodesdale Segment or Rhodesdale gneiss to the north.
c. 3.340 Ma – Johannesburg Dome forms in South Africa: located in the central part of Kaapvaal Craton and consists of trondhjemitic and tonalitic granitic rocks intruded into mafic-ultramafic greenstone – the oldest granitoid phase recognised so far.
c. 3,260 Ma – One of the largest recorded impact events occurs near the Barberton Greenstone Belt, when a 58 km (36 mi) asteroid leaves a crater almost 480 km (300 mi) across – two and a half times larger in diameter than the Chicxulub crater.[14]
Mesoarchean Era
c. 3,200 Ma – Mesoarchean Era starts. Onverwacht series in South Africa form – contain some of the oldest microfossils mostly spheroidal and carbonaceous alga-like bodies.
c. 3,100 Ma – Fig Tree Formation: second round of fossilizations including Archaeosphaeroides barbertonensis and Eobacterium. Gneiss and greenstone belts in the Baltic Shield are laid down in Kola Peninsula, Karelia and northeastern Finland.
c. 3,000 Ma – Humboldt Orogeny in Antarctica: possible formation of Humboldt MountainsinQueen Maud Land. Photosynthesizing cyanobacteria evolve; they use water as a reducing agent, thereby producing oxygen as a waste product. The oxygen initially oxidizes dissolved iron in the oceans, creating iron ore – over time oxygen concentration in the atmosphere slowly rises, acting as a poison for many bacteria. As Moon is still very close to Earth and causes tides 1,000 feet (305 m) high[citation needed], the Earth is continually wracked by hurricane-force winds – these extreme mixing influences are thought to stimulate evolutionary processes. Rise of Stromatolites: microbial mats become successful forming the first reef building communities on Earth in shallow warm tidal pool zones (to 1.5 Gyr). Tanzania Craton forms.
c. 2,940 Ma – Yilgarn Craton of western Australia forms by the accretion of a multitude of formerly present blocks or terranes of existing continental crust.
c. 2,900 Ma – Assembly of the Kenorland supercontinent, based upon the core of the Baltic shield, formed at c.3100 Ma. Narryer Gneiss Terrane (including Jack Hills) of Western Australia undergoes extensive metamorphism.
Neoarchean Era
c. 2,800 Ma – Neoarchean Era starts. Breakup of the Vaalbara: Breakup of supercontinent Ur as it becomes a part of the major supercontinent Kenorland. Kaapvaal and Zimbabwe cratons join together.
c. 2,770 Ma – Formation of Hamersley Basin on the southern margin of Pilbara Craton – last stable submarine-fluviatile environment between the Yilgarn and Pilbara prior to rifting, contraction and assembly of the intracratonic Gascoyne Complex.
c. 2,750 Ma – Renosterkoppies Greenstone Belt forms on the northern edge of the Kaapvaal Craton.
c. 2,705 Ma – Major komatiite eruption, possibly global[13] – possible mantle overturn event.
c. 2,704 Ma – Blake River Megacaldera Complex: second phase results in creation of 30 km long, 15 km wide northwest–southeast trending New Senator Caldera – thick massive mafic sequences which has been inferred to be a subaqueous lava lake.
c. 2,700 Ma – Biomarkers of cyanobacteria discovered, together with steranes (sterolsofcholesterol), associated with films of eukaryotes, in shales located beneath banded iron formation hematite beds, in Hamersley Range, Western Australia;[15] skewed sulfur isotope ratios found in pyrites show a small rise in oxygen concentration in the atmosphere;[16]Sturgeon Lake Caldera forms in Wabigoon greenstone belt – contains well preserved homoclinal chain of greenschist facies, metamorphosed intrusive, volcanic and sedimentary layers (Mattabi pyroclastic flow considered third most voluminous eruptive event); stromatolites of Bulawayo series in Zimbabwe form – first verified reef community on Earth.
c. 2,696 Ma – Blake River Megacaldera Complex: third phase of activity constructs classic east-northeast striking Noranda Caldera which contains a 7-to-9-km-thick succession of mafic and felsic rocks erupted during five major series of activity. Abitibi greenstone belt in present-day Ontario and Quebec begins to form: considered world's largest series of Archean greenstone belts, appears to represent a series of thrusted subterranes.
c. 2,690 Ma – Formation of high pressure granulites in the Limpopo Central Region.
c. 2,650 Ma – Insell Orogeny: occurrence of a very high grade discrete tectonothermal event (a UHT metamorphic event).
c. 2,600 Ma – Oldest known giant carbonate platform.[13] Saturation of oxygen in ocean sediments is reached as oxygen now begins to dramatically appear in Earth's atmosphere.
c. 2,400 Ma – Huronianglaciation starts, probably from oxidation of earlier methane greenhouse gas produced by burial of organic sediments of photosynthesizers. Formation of Dharwar Craton in southern India.
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. 2,090 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
c. 2,050 Ma – Orosirian Period starts. Significant orogeny in most continents.
c. 2,005 Ma – Glenburgh Orogeny (to c. 1,920 Ma) begins: Glenburgh TerraneinwesternAustralia begins to stabilize during period of substantial granite magmatism and deformation; Halfway Gneiss and Moogie Metamorphics result. Dalgaringa Supersuite (to c. 1,985 Ma), comprising sheets, dykes and viens of mesocratic and leucocratic tonalite, stabilizes.
c. 1,830 Ma – Capricorn Orogeny (1.83–1.78 Gyr) stabilizes central and northern Gascoyne Complex: formation of pelitic and psammitic schists known as Morrissey Metamorphics and depositing Pooranoo Metamorphics an amphibolite facies
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. 1,680 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 SouthernAustralia – formation of Gawler Range including picturesque Conical Hill Track and "Organ Pipes" waterfall
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 algaBangiomorpha 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. 1,000 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 to 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 EarthorSlushball Earth) at least 3 times. The Sturtianglaciation 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 skeletonsofspicules 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. 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. 518 Ma – Chengjiang biota flourishes – Maotianshan Shales reveal numerous invertebrates and arthropods that appear in the Burgess shales suggesting their range is global and includes a number of chordates including Haikouella, Yunnanozoon and early fish like Haikouichthys.
c. 514 Ma – Paradoxides trilobites appear, the largest members of the Cambrian Trilobites.
c. 490 Ma – Beginning of the Caledonian Orogeny as three continents and terranes of Laurentia, Baltica and Avalonia collide resulting in mountain-building recorded in the northern parts of Ireland and Britain, the Scandinavian Mountains, Svalbard, eastern Greenland and parts of north-central Europe.
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. 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
c. 214 Ma - Plateosaurus, a basal sauropodomorph or so-called "prosauropod" evolves in what is now Central and Northern Europe, Greenland and North America
c. 68 Ma – Tyrannosaurus rex evolves. Earliest species of Triceratops. Quetzalcoatlus, one of the largest flying animals to ever live, first appears in the fossil record.
c. 62 Ma – Fall in sea level and the retreat of inland seas completes the emergence of North America; First penguins appear – Genus Crossvallia, the earliest known birds suited to an aquatic lifestyle, alongside Kupoupou appear in the fossil record of Antarctica (from the Cross Valley Formation on Seymour Island) and New Zealand (Takatika Grit formation of the Chatham Islands); Pelagornithidae or bony-toothed birds, group of large seabirds noted for tooth-like points on their beak's edges first appear – Pseudoteeth of pelagornithids do not seem to have had serrated or otherwise specialized cutting edges and were useful to hold prey for swallowing whole and would have consisted of soft-bodied organisms like Cephalopods; .
c. 60 Ma – Evolution of the first primates and miacids. Flightless birds diversify.
c. 5.33 Ma – Zanclean flood: the Strait of Gibraltar opens for the last (and current) time and water from the Atlantic Sea fills again the Mediterranean Sea basin. The deep canyon carved by the Eonile during the Messinian Salinity Crisis is filled with seawater up to at least Aswan. The modern Nile starts filling this sea branch with sediments, slowly creating the Nile Valley.
c. 5.333 Ma – Pliocene epoch begins. First tree sloths. First large vultures. Nimravids go extinct.
c. 5.0 Ma – The Colorado Plateau reaches its present height, and the course of the Colorado River becomes close to the present one.
c. 0.7 Ma: oldest archaic hominins that broke away from the modern human lineage that were found to have inserted into the Sub-Saharan African population genome approximately 35,000 years ago.[24]
This was initially deemed the "fourth" period after the now-obsolete "primary", "secondary" and "tertiary" periods.
Visual summary
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.
Consilience, evidence from independent, unrelated sources can "converge" on strong conclusions
References
^Amelin, Yuri, Alexander N. Krot, Ian D. Hutcheon, & Alexander A. Ulyanov, "Lead Isotopic Ages of Chondrules and Calcium-Aluminum-Rich Inclusions" (Science, 6 September 2002: Vol. 297. no. 5587, pp. 1678–83)
^"Stratigraphic Chart 2022"(PDF). International Stratigraphic Commission. February 2022. Archived(PDF) from the original on 2 April 2022. Retrieved 25 April 2022.
^Taylor, G. Jeffrey (2006), "Wandering Gas Giants and Lunar Bombardment: Outward migration of Saturn might have triggered a dramatic increase in the bombardment rate on the Moon 3.9 billion years ago, an idea testable with lunar samples" [1]Archived 2018-01-01 at the Wayback Machine
^Mojzis, S, et al. (1996), "Evidence for Life on Earth before 3800 million years ago", (Nature, 384)
^Czaja, Andrew D.; Johnson, Clark M.; Beard, Brian L.; Roden, Eric E.; Li, Weiqiang; Moorbath, Stephen (February 2013). "Biological Fe oxidation controlled deposition of banded iron formation in the ca. 3770Ma Isua Supracrustal Belt (West Greenland)". Earth and Planetary Science Letters. 363: 192–203. Bibcode:2013E&PSL.363..192C. doi:10.1016/j.epsl.2012.12.025.
^Yoko Ohtomo; Takeshi Kakegawa; Akizumi Ishida; Toshiro Nagase; Minik T. Rosing (8 December 2013). "Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks". Nature Geoscience. 7 (1): 25–28. Bibcode:2014NatGe...7...25O. doi:10.1038/ngeo2025.
^Butterfield, NJ. (2000). "Bangiomorpha pubescens n. gen., n. sp.: implications for the evolution of sex, multicellularity and the Mesoproterozoic/Neoproterozoic radiation of eukaryotes". Paleobiology. 26 (3): 386–404. doi:10.1666/0094-8373(2000)026<0386:BPNGNS>2.0.CO;2. S2CID36648568.
^Rooney, A. D.; Strauss, J. V.; Brandon, A. D.; MacDonald, F. A. (2015). "A Cryogenian chronology: Two long-lasting synchronous Neoproterozoic glaciations". Geology. 43 (5): 459. Bibcode:2015Geo....43..459R. doi:10.1130/G36511.1.
