Timetable of the Precambrian
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This timeline of natural history summarizes significant
geological Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other E ...
and biological events from the
formation of the Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surface ...
to the arrival of modern
human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
s. Times are listed in millions of years, or megaanni ( Ma).


Dating of the geologic record

The
geologic record The geologic record in stratigraphy, paleontology and other natural sciences refers to the entirety of the layers of rock strata. That is, deposits laid down by volcanism or by deposition of sediment derived from weathering detritus (clays, sand ...
is the strata (layers) of rock in the planet's crust and the science of
geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ea ...
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 Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares ...
measures the steady decay of
radioactive element A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transfe ...
s 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
isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numb ...
s of each
chemical element A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cannot be broken down into simpler sub ...
. Isotopes are
atom Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas, ...
s of the element that differ in
mass Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different eleme ...
but share the same general properties. Geologists are most interested in the decay of isotopes carbon-14 (into
nitrogen-14 Natural nitrogen (7N) consists of two stable isotopes: the vast majority (99.6%) of naturally occurring nitrogen is nitrogen-14, with the remainder being nitrogen-15. Fourteen radioisotopes are also known, with atomic masses ranging from 10 to 25, ...
) and
potassium-40 Potassium-40 (40K) is a radioactive isotope of potassium which has a long half-life of 1.25 billion years. It makes up about 0.012% (120 ppm) of the total amount of potassium found in nature. Potassium-40 undergoes three types of radioactive d ...
(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 Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin ...
, charcoal,
paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distrib ...
,
fabric Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, different fabric types, etc. At first, the word "textiles" only referred to woven fabrics. However, weaving is not th ...
s,
fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
s and
shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard o ...
s. 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
extinction Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
s (e.g., the
dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
s) and with the appearances of new species (e.g., hominids).


The earliest Solar System

In the earliest
Solar System The Solar System Capitalization 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 "Solar ...
history, the Sun, the
planetesimal Planetesimals are solid objects thought to exist in protoplanetary disks and debris disks. Per the Chamberlin–Moulton planetesimal hypothesis, they are believed to form out of cosmic dust grains. Believed to have formed in the Solar System a ...
s 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 Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
and
Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
. * c. 4,570 Ma – A supernova explosion (known as the primal supernova) seeds our galactic neighborhood with
heavy element upright=1.2, Crystals of osmium, a heavy metal nearly twice as dense as lead">lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead Heavy metals are generally defined as ...
s that will be incorporated into the Earth, and results in a
shock wave In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a me ...
in a dense region of the
Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ...
galaxy. The Ca-Al-rich inclusions, which formed 2 million years before the
chondrules A chondrule (from Ancient Greek χόνδρος ''chondros'', grain) is a round grain found in a chondrite. Chondrules form as molten or partially molten droplets in space before being accreted to their parent asteroids. Because chondrites repres ...
, are a key signature of a supernova explosion. * c. 4,567 ±3 Ma – Rapid collapse of
hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...
molecular cloud A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit absorption nebulae, the formation of molecules (most commonly molecular hydroge ...
, forming a third-generation Population I star, the
Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
, in a region of the
Galactic Habitable Zone In astrobiology and planetary astrophysics, the galactic habitable zone is the region of a galaxy in which life might most likely develop. The concept of a galactic habitable zone analyzes various factors, such as metallicity (the presence of elem ...
(GHZ), about 25,000 light years from the center of the
Milky Way Galaxy The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ...
. * c. 4,566 ±2 Ma – A
protoplanetary disc A protoplanetary disk is a rotating circumstellar disc of dense gas and dust surrounding a stellar evolution, young newly formed star, a T Tauri star, or Herbig Ae/Be star. The protoplanetary disk may also be considered an accretion disk for th ...
(from which Earth eventually forms) emerges around the young
Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
, which is in its
T Tauri T Tauri is a variable star in the constellation Taurus, the prototype of the T Tauri stars. It was discovered in October 1852 by John Russell Hind. T Tauri appears from Earth amongst the Hyades cluster, not far from ε Tauri, but i ...
stage. * c. 4,560–4,550 Ma – Proto-Earth forms at the outer (cooler) edge of the
habitable zone In astronomy and astrobiology, the circumstellar habitable zone (CHZ), or simply the habitable zone, is the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressure.J. F. Kast ...
of the
Solar System The Solar System Capitalization 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 "Solar ...
. 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 Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Ea ...
and
carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...
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.


Precambrian Supereon

* c. 4,533 Ma – The Precambrian (to c. 539 Ma), now termed a "supereon" but formerly an
era An era is a span of time defined for the purposes of chronology or historiography, as in the regnal eras in the history of a given monarchy, a calendar era used for a given calendar, or the geological eras defined for the history of Earth. Comp ...
, 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.


Hadean Eon

* c. 4,533 Ma – Hadean Eon, Precambrian Supereon and unofficial Cryptic era start as the
Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
system forms, possibly as a result of a glancing collision between proto-Earth and the hypothetical
protoplanet A protoplanet is a large planetary embryo that originated within a protoplanetary disc and has undergone internal melting to produce a differentiated interior. Protoplanets are thought to form out of kilometer-sized planetesimals that gravitation ...
Theia In Greek mythology, Theia (; grc, Θεία, Theía, divine, also rendered Thea or Thia), also called Euryphaessa ( grc, Εὐρυφάεσσα) "wide-shining", is one of the twelve Titans, the children of the earth goddess Gaia and the Sky deity ...
. (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 The pre-Nectarian period of the lunar geologic timescale runs from 4.533 billion years ago (the time of the initial formation of the Moon) to 3.920 billion years ago, when the Nectaris Basin was formed by a large impact. It is followed by the Necta ...
period starts. Earth was covered by a
magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...
tic ocean deep resulting from the impact energy from this and other
planetesimal Planetesimals are solid objects thought to exist in protoplanetary disks and debris disks. Per the Chamberlin–Moulton planetesimal hypothesis, they are believed to form out of cosmic dust grains. Believed to have formed in the Solar System a ...
s during the early bombardment phase, and energy released by the planetary core forming. Outgassing from crustal rocks gives Earth a reducing atmosphere of
methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Ea ...
,
nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
,
hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...
,
ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...
, and
water vapour (99.9839 °C) , - , Boiling point , , - , specific gas constant , 461.5 J/( kg·K) , - , Heat of vaporization , 2.27 MJ/kg , - , Heat capacity , 1.864 kJ/(kg·K) Water vapor, water vapour or aqueous vapor is the gaseous pha ...
, with lesser amounts of hydrogen sulfide,
carbon monoxide Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...
, then
carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...
. 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 The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between . The composition of the sol ...
sweeps the Earth-Moon system clear of debris (mainly dust and gas). End of the Early Bombardment Phase.
Basin Groups Basin Groups refers to 9 subdivisions of the lunar Pre-Nectarian geologic period. It is the second era of the Hadean. Definition The motivation for creating the Basin Groups subdivisions was to place 30 pre-Nectarian impact basins into 9 relativ ...
Era begins on Earth. * c. 4,450 Ma – 100 million years after the Moon formed, the first lunar crust, formed of lunar
anorthosite Anorthosite () is a phaneritic, intrusive igneous rock characterized by its composition: mostly plagioclase feldspar (90–100%), with a minimal mafic component (0–10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most ...
, differentiates from lower
magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...
s. The earliest Earth crust probably forms similarly out of similar material. On Earth the
pluvial In geology and climatology, a pluvial is either a modern climate characterized by relatively high precipitation or an interval of time of variable length, decades to thousands of years, during which a climate is characterized by relatively high ...
period starts, in which the Earth's crust cools enough to let oceans form. * c. 4,404 Ma – First known
mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...
, found at
Jack Hills 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 4.39 billion years ago. These zircons have enabl ...
in
Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
.
Detrital Detritus (; adj. ''detrital'' ) is particles of rock derived from pre-existing rock through weathering and erosion.Essentials of Geology, 3rd Ed, Stephen Marshak, p G-7 A fragment of detritus is called a clast.Essentials of Geology, 3rd Ed, Stephe ...
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 t ...
s show presence of a solid crust and liquid
water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...
. Latest possible date for a secondary atmosphere to form, produced by the Earth's crust
outgassing Outgassing (sometimes called offgassing, particularly when in reference to indoor air quality) is the release of a gas that was dissolved, trapped, frozen, or absorbed in some material. Outgassing can include sublimation and evaporation (which ...
, reinforced by water and possibly
organic molecule In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...
s delivered by
comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ...
impacts and carbonaceous chondrites (including type CI shown to be high in a number of amino acids and
polycyclic aromatic hydrocarbon A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings and the three-ring compounds anthracene and phenanthrene. ...
s (PAH)). * c. 4,300 Ma – Nectarian Era begins on Earth. * c. 4,250 Ma – Earliest evidence for life, based on unusually high amounts of light isotopes of carbon, a common sign of
life Life is a quality that distinguishes matter that has biological processes, such as Cell signaling, signaling and self-sustaining processes, from that which does not, and is defined by the capacity for Cell growth, growth, reaction to Stimu ...
, found in Earth's oldest mineral deposits located in the
Jack Hills 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 4.39 billion years ago. These zircons have enabl ...
of
Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
. * c. 4,100 Ma – Early Imbrian Era begins on Earth.
Late heavy bombardment The Late Heavy Bombardment (LHB), or lunar cataclysm, is a hypothesized 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 hypot ...
of the Moon (and probably of the Earth as well) by
bolide A bolide is normally taken to mean an exceptionally bright meteor, but the term is subject to more than one definition, according to context. It may refer to any large crater-forming body, or to one that explodes in the atmosphere. It can be a ...
s and asteroids, produced possibly by the
planetary migration Planetary migration occurs when a planet or other body in orbit around a star interacts with a disk of gas or planetesimals, resulting in the alteration of its orbital parameters, especially its semi-major axis. Planetary migration is the most li ...
of Neptune into the Kuiper belt as a result of
orbital resonance In celestial mechanics, orbital resonance occurs when orbiting bodies exert regular, periodic gravitational influence on each other, usually because their orbital periods are related by a ratio of small integers. Most commonly, this relationsh ...
s between
Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...
and Saturn. "Remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia. Early edition, published online before print. According to one of the researchers, "If life arose relatively quickly on Earth ... then it could be common in the
universe The universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy. The Big Bang theory is the prevailing cosmological description of the development of the universe. ...
." * c. 4,030 Ma – Acasta Gneiss of Northwest Territories, Canada, first known
oldest rock 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 ...
, or aggregate of minerals.


Archean Eon


Eoarchean Era

* c. 4,000 Ma – Archean Eon and
Eoarchean The Eoarchean (; also spelled Eoarchaean) is the first era of the Archean Eon of the geologic record. It spans 400 million years, from the end of the Hadean Eon 4 billion years ago (4000 Mya) to the start of the Paleoarchean Era 3600 Mya. Th ...
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 The Napier Mountains are a group of close set peaks, the highest being Mount Elkins, at about 2,300 meters above sea level. This mountain range is located in Enderby Land, in the claimed Australian Antarctic Territory, East Antarctica. Location ...
Orogeny forces of faulting and folding create first
metamorphic rocks 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, caus ...
. Origins of life. * c. 3,930 Ma – Possible stabilization of Canadian Shield begins * c. 3,920–3,850 Ma – Final phase of Late Heavy Bombardment * c. 3,850 Ma – Greenland apatite shows evidence of 12C enrichment, characteristic of the presence of photosynthetic life. * c. 3,850 Ma – Evidence of life: Akilia Island
graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on lar ...
off Western
Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland i ...
contains evidence of
kerogen Kerogen is solid, insoluble organic matter in sedimentary rocks. Comprising an estimated 1016 tons of carbon, it is the most abundant source of organic compounds on earth, exceeding the total organic content of living matter 10,000-fold. It ...
, of a type consistent with
photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...
. * c. 3,800 Ma – Oldest
banded iron formation Banded iron formations (also known as banded ironstone formations or BIFs) are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. They can be up to several hundred meters in thickness ...
s found. First complete continental masses or
cratons A craton (, , or ; from grc-gre, κράτος "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging and ...
, formed of
granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies under ...
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 The East European Craton (EEC) is the core of the Baltica proto- plate and consists of three crustal regions/segments: Fennoscandia to the northwest, Volgo-Uralia to the east, and Sarmatia to the south. Fennoscandia includes the Baltic Shield ( ...
begins to formfirst rocks of the
Ukrainian Shield In geology the Ukrainian Shield (or Ukrainian Crystalline Massif) is the southwest shield of the East European craton. The Ukrainian Shield and the Voronezh Massif consist of 3.2-3.8 Ga Archaean crust in the southwest and east, and 2.3-2.1 Ga ...
and
Voronezh Massif Voronezh Massif (also Voronezh Anteclise russian: Воронежская антеклиза, or Voronezh Uplift) is a tectonic anteclise in the south of the Central Russian Upland with a high occurrence of the Precambrian basement. It lies to th ...
are laid down * c. 3,750 Ma –
Nuvvuagittuq Greenstone Belt The Nuvvuagittuq Greenstone Belt (NGB; Inuktitut: ) is a sequence of metamorphosed mafic to ultramafic Volcanic rock, volcanic and associated sedimentary rocks (a greenstone belt) located on the eastern shore of Hudson Bay, 40 km southeast of ...
forms * c. 3,700 Ma –
Graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on lar ...
found to be biogenic in 3.7 billion-year-old
metasedimentary rocks In geology, metasedimentary rock is a type of metamorphic rock. Such a rock was first formed through the deposition and solidification of sediment Sediment is a naturally occurring material that is broken down by processes of weathering and e ...
discovered in
Western Greenland Kitaa, originally Vestgrønland ("West Greenland"), is a former administrative division of Greenland. It was by far the most populated of the divisions, being home to almost 90% of the total population. The divisions were de facto replaced by st ...
Stabilization of Kaapval craton begins: old tonaltic
gneiss Gneiss ( ) 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. Gneiss forms at higher temperatures a ...
es laid down


Paleoarchean Era

* c. 3,600 Ma –
Paleoarchean The Paleoarchean (), also spelled Palaeoarchaean (formerly known as early Archean), is a geologic era within the Archaean Eon. The name derives from Greek "Palaios" ''ancient''. It spans the period of time . The era is defined chronometrically a ...
Era starts. Possible assembly of the
Vaalbara Vaalbara was an Archean supercontinent consisting of the Kaapvaal Craton (now in eastern South Africa) and the Pilbara Craton (now in north-western Western Australia). E. S. Cheney derived the name from the last four letters of each craton's name ...
supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leav ...
; 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 The Pilbara Craton is an old and stable part of the continental lithosphere located in the Pilbara region of Western Australia. The Pilbara Craton is one of only two pristine Archaean 3.6–2.7 Ga (billion years ago) crusts identified on the ...
stabilizes. Formation of
Barberton greenstone belt The Barberton Greenstone Belt is situated on the eastern edge of Kaapvaal Craton in South Africa. It is known for its gold mineralisation and for its komatiites, an unusual type of ultramafic volcanic rock named after the Komati River that flows t ...
: Makhonjwa Mountains uplifts on the eastern edge of Kaapval craton, oldest mountains in Africaarea called the "genesis of life" for exceptional preservation of fossils.
Narryer Gneiss Terrane 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 ...
stabilizes: these gneisses become the "bedrock" for the formation of the
Yilgarn Craton 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 b ...
in Australianoted for the survival of the
Jack Hills 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 4.39 billion years ago. These zircons have enabl ...
where the oldest mineral, a zircon was uncovered. * c. 3,500 Ma – Lifetime of the
Last universal ancestor The last universal common ancestor (LUCA) is the most recent population from which all organisms now living on Earth share common descent—the most recent common ancestor of all current life on Earth. This includes all cellular organisms; th ...
: split between bacteria and archaea occurs as "tree of life" begins branching outvarieties of
Eubacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were amon ...
begin to radiate out globally. Fossils resembling cyanobacteria, found at Warrawoona,
Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
. * c. 3,480 Ma – Fossils of
microbial mat A microbial mat is a multi-layered sheet of microorganisms, mainly bacteria and archaea, or bacteria alone. Microbial mats grow at interfaces between different types of material, mostly on submerged or moist surfaces, but a few survive in deserts ...
found in 3.48 billion-year-old
sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...
discovered in
Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
. First appearance of stromatolitic organisms that grow at interfaces between different types of material, mostly on submerged or moist surfaces. * c. 3,460 Ma – Fossils of
bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...
in
chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a ...
. 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. 3.400 Ma – Eleven
taxa In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...
of
prokaryote A prokaryote () is a single-celled organism that lacks a nucleus and other membrane-bound organelles. The word ''prokaryote'' comes from the Greek πρό (, 'before') and κάρυον (, 'nut' or 'kernel').Campbell, N. "Biology:Concepts & Conne ...
s are preserved in the Apex Chert of the Pilbara craton in Australia. Because
chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a ...
is fine-grained
silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is ...
-rich
microcrystalline A microcrystalline material is a crystallized substance or rock that contains small crystals visible only through microscopic examination. There is little agreement on the range of crystal sizes that should be regarded as microcrystalline, but th ...
,
cryptocrystalline Cryptocrystalline is a rock texture made up of such minute crystals that its crystalline nature is only vaguely revealed even microscopically in thin section by transmitted polarized light. Among the sedimentary rocks, chert and flint are crypt ...
or microfibrious material, it preserves small fossils quite well. Stabilization of Baltic Shield begins. * c. 3.340 Ma – Johannesburg Dome forms in
South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...
: located in the central part of Kaapvaal Craton and consists of trondhjemitic and tonalitic granitic rocks intruded into mafic-ultramafic greenstonethe oldest granitoid phase recognised so far. * c. 3,300 Ma – Onset of compressional tectonics. Intrusion of granitic
plutons In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...
on the Kaapvaal Craton. * c. 3,260 Ma – One of the largest recorded impact events occurs near the
Barberton Greenstone Belt The Barberton Greenstone Belt is situated on the eastern edge of Kaapvaal Craton in South Africa. It is known for its gold mineralisation and for its komatiites, an unusual type of ultramafic volcanic rock named after the Komati River that flows t ...
, 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 The Chicxulub crater () is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is offshore near the community of Chicxulub, after which it is named. It was formed slightly over 66 million years ago when a large a ...
.


Mesoarchean Era

* c. 3,200 Ma –
Mesoarchean The Mesoarchean (, also spelled Mesoarchaean) is a geologic era in the Archean Eon, spanning , which contains the first evidence of modern-style plate subduction and expansion of microbial life. The era is defined chronometrically and is not r ...
Era starts. Onverwacht series in South Africa formcontain some of the oldest microfossils mostly spheroidal and carbonaceous alga-like bodies. * c. 3,200–2,600 Ma – Assembly of the Ur supercontinent to cover between 12 and 16% of the current
continental crust Continental crust is the layer of igneous, sedimentary, and metamorphic rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called '' sial'' be ...
. Formation of
Limpopo Belt The Limpopo Belt is located in South Africa and Zimbabwe, runs E-NE, and joins the Kaapvaal Craton to the south with the Zimbabwe Craton to the north. The belt is of high-grade metamorphic rocks that have undergone a long cycle of metamorphism and ...
. * 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 sjd, Куэлнэгк нёа̄ррк , image_name= Kola peninsula.png , image_caption= Kola Peninsula as a part of Murmansk Oblast , image_size= 300px , image_alt= , map_image= Murmansk in Russia.svg , map_caption = Location of Murmansk Oblas ...
, Karelia and northeastern
Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of B ...
. * c. 3,000 Ma – Humboldt Orogeny in Antarctica: possible formation of Humboldt Mountains in
Queen Maud Land Queen Maud Land ( no, Dronning Maud Land) is a roughly region of Antarctica claimed by Norway as a dependent territory. It borders the claimed British Antarctic Territory 20° west and the Australian Antarctic Territory 45° east. In addi ...
. 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 oreover 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, the Earth is continually wracked by hurricane-force windsthese extreme mixing influences are thought to stimulate evolutionary processes. Rise of
Stromatolites Stromatolites () or stromatoliths () are layered sedimentary formations (microbialite) that are created mainly by photosynthetic microorganisms such as cyanobacteria, sulfate-reducing bacteria, and Pseudomonadota (formerly proteobacteria). Th ...
: microbial mats become successful forming the first
reef A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock o ...
building communities on Earth in shallow warm tidal pool zones (to 1.5 Gyr).
Tanzania Craton The Tanzania Craton is an old and stable part of the continental lithosphere in central Tanzania. Some of the rocks are over 3 billion years old. Setting The Tanzania Craton forms the highest part of the East African Plateau. The craton is surr ...
forms. * c. 2,940 Ma –
Yilgarn Craton 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 b ...
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 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 (2.72 Ga) by the accretion of Neoarchaean cratons and the formation of new continental crust. ...
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 The Neoarchean (; also spelled Neoarchaean) is the last geologic era in the Archean eon that spans from 2800 to 2500 million years ago—the period being defined chronometrically and not referencing a specific level in a rock section on Ear ...
Era starts. Breakup of the
Vaalbara Vaalbara was an Archean supercontinent consisting of the Kaapvaal Craton (now in eastern South Africa) and the Pilbara Craton (now in north-western Western Australia). E. S. Cheney derived the name from the last four letters of each craton's name ...
: 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 Cratonlast 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. 2,736 Ma – Formation of the
Temagami Greenstone Belt The Temagami Greenstone Belt (TGB) is a small 2.7 billion year old greenstone belt in the Temagami region of Northeastern Ontario, Canada. It represents a feature of the Superior craton, an ancient and stable part of the Earth's lithosphere ...
in
Temagami Temagami, formerly spelled as Timagami, is a municipality in northeastern Ontario, Canada, in the Nipissing District with Lake Temagami at its heart. The Temagami region is known as ''n'Daki Menan'', the homeland of the area's First Nations c ...
,
Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...
,
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
. * c. 2,707 Ma – Blake River Megacaldera Complex begins to form in present-day
Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...
and
Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...
first known Precambrian supervolcanofirst phase results in creation of 8 km long, 40 km wide, east–west striking Misema Caldera *coalescence of at least two large mafic shield volcanoes. * c. 2,705 Ma – Major komatiite eruption, possibly globalpossible 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 Calderathick massive mafic sequences which has been inferred to be a subaqueous lava lake. * c. 2,700 Ma – Biomarkers of cyanobacteria discovered, together with steranes ( sterols of
cholesterol Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell mem ...
), associated with films of eukaryotes, in shales located beneath banded iron formation hematite beds, in Hamersley Range, Western Australia; skewed sulfur isotope ratios found in pyrites show a small rise in oxygen concentration in the atmosphere;
Sturgeon Lake Caldera Sturgeon Lake Caldera is a large extinct caldera complex in Kenora District of Northwestern Ontario, Canada. It is one of the world's best preserved mineralized Neoarchean caldera complexes, containing well-preserved mafic-intermediate pillow ...
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 The Abitibi greenstone belt is a 2,800-to-2,600-million-year-old greenstone belt that spans across the Ontario–Quebec border in Canada. It is mostly made of volcanic rocks, but also includes ultramafic rocks, mafic intrusions, granitoid rocks, ...
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. Saturation of oxygen in ocean sediments is reached as oxygen now begins to dramatically appear in Earth's atmosphere.


Proterozoic Eon

The Proterozoic (from c. 2500 Ma to c. 541 Ma) saw the first traces of biological activity.
Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
remains of
bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...
and algae.


Paleoproterozoic Era


Siderian Period

* c. 2,500 Ma – Proterozoic Eon, Paleoproterozoic Era, and Siderian Period start. Oxygen saturation in the oceans is reached:
Banded iron formations Banded iron formations (also known as banded ironstone formations or BIFs) are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. They can be up to several hundred meters in thickness a ...
form and saturate ocean floor depositswithout an oxygen sink, Earth's atmosphere becomes highly oxygenic. Great Oxygenation Event led by cyanobacteria's oxygenic photosynthesisvarious forms of Archaea and anoxic bacteria become extinct in first great extinction event on Earth.
Algoman Orogeny 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 provinc ...
or Kenoran: assembly of
Arctica Arctica or Arctida was an ancient continent which formed approximately 2.565  billion years ago in the Neoarchean era. It was made of Archaean cratons, including the Siberian Craton, with its Anabar/Aldan shields in Siberia, and the Sla ...
out of the Canadian
Laurentian Shield The Canadian Shield (french: Bouclier canadien ), also called the Laurentian Plateau, is a geologic shield, a large area of exposed Precambrian igneous and high-grade metamorphic rocks. It forms the North American Craton (or Laurentia), the an ...
and Siberian
craton A craton (, , or ; from grc-gre, κράτος "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging an ...
formation of Angaran Shield and Slave Province. * c. 2,440 Ma – Formation of
Gawler Craton The Gawler Craton covers approximately 440,000 square kilometres of central South Australia. Its Precambrian crystalline basement crustal block was cratonised ca. 1550–1450 Ma. Prior to 1550 Ma the craton comprised a number of active Proter ...
in Australia. * c. 2,400 Ma – Huronian
glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate be ...
starts, probably from oxidation of earlier methane greenhouse gas produced by burial of organic sediments of photosynthesizers. First cyanobacteria. Formation of Dharwar Craton in southern India. * c. 2,400 Ma – Dharwar Craton in southern India stabilizes.


Rhyacian Period

* c. 2,300 Ma –
Rhyacian The Rhyacian Period (; grc, ῥύαξ, translit=rhýax, meaning "stream of lava") is the second geologic period in the Paleoproterozoic Era and lasted from Mya to Mya (million years ago). Instead of being based on stratigraphy, these dates are ...
period starts. * c. 2,250 Ma –
Bushveld Igneous Complex The Bushveld Igneous Complex (BIC) is the largest layered igneous intrusion within the Earth's crust. It has been tilted and eroded forming the outcrops around what appears to be the edge of a great geological basin: the Transvaal Basin. It i ...
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 The Transvaal Basin is one of three basins of the Transvaal Supergroup on the Kaapvaal craton. The evolution of this 2.65–2.05 Ga Neoarchaean– Palaeoproterozoic basin is thought to have been derived largely from magmatism, palaeoclimate and ...
begins. * c. 2,200–1800 Ma – Continental Red Beds found, produced by iron in weathered sandstone being exposed to oxygen.
Eburnean Orogeny The Eburnean orogeny, or Eburnean cycle, was a series of tectonic, metamorphic and plutonic events in what is now West Africa during the Paleoproterozoic era about 2200–2000 million years ago. During this period the Birimian domain in West Afr ...
, series of tectonic, metamorphic and plutonic events establish Eglab Shield to the north of
West African Craton 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.Jessell M.W., Liégeo ...
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. 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 A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate be ...
ends. Earliest known eukaryote fossils found. Earliest multicellular organisms collectively referred to as the "Gabonionta" ( Francevillian Group Fossil);
Wopmay orogen The Wopmay orogen is a Paleoproterozoic orogenic belt in northern Canada which formed during the collision between the Hottah terrane (north of the Hottah Lake), a continental magmatic arc, and the Archean Slave Craton at about 1.88 Ga (bi ...
y 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

* c. 2,050 Ma –
Orosirian The Orosirian Period (; grc, ὀροσειρά, translit=oroseirá, meaning "mountain range") is the third geologic period in the Paleoproterozoic era (geology), Era and lasted from annum, Mya to Mya (million years ago). Instead of being based ...
Period starts. Significant orogeny in most continents. * c. 2,023 Ma –
Vredefort impact structure The Vredefort impact structure is the largest verified impact structure on Earth. The crater, which has since been eroded away, was around across when it was formed. The remaining structure, comprising the deformed underlying bedrock, is loca ...
forms. * c. 2,005 Ma – Glenburgh Orogeny (to c. 1,920 Ma) begins: Glenburgh Terrane in western Australia 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. 2,000 Ma – The lesser
supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leav ...
Atlantica Atlantica ( gr, Ατλαντικα; ''Atlantika'') is an ancient continent that formed during the Proterozoic about (two billion years ago, Ga) from various 2 Ga cratons located in what are now West Africa and eastern South America. The name, ...
forms. The
Oklo Oklo is a region near the town of Franceville, in the Haut-Ogooué province of the Central African country of Gabon. Several natural nuclear fission reactors were discovered in the uranium mines in the region in 1972. History Gabon was a Fren ...
natural nuclear reactor of
Gabon Gabon (; ; snq, Ngabu), officially the Gabonese Republic (french: République gabonaise), is a country on the west coast of Central Africa. Located on the equator, it is bordered by Equatorial Guinea to the northwest, Cameroon to the nort ...
produced by uranium-precipitant bacteria. First
acritarch Acritarchs are organic microfossils, known from approximately 1800 million years ago to the present. The classification is a catch all term used to refer to any organic microfossils that cannot be assigned to other groups. Their diversity refle ...
s. * c. 1,900–,880 Ma – Gunflint chert biota forms flourishes including prokaryotes like Kakabekia, Gunflintia, Animikiea and Eoastrion * c. 1,850 Ma – Sudbury impact structure.
Penokean orogeny The Penokean orogeny was a mountain-building episode that occurred in the early Proterozoic about 1.86 to 1.83 billion years ago, in the area of Lake Superior, North America. The core of this orogeny, the Churchill Craton, is composed of terranes ...
. First eukaryotes. Bacterial viruses ( bacteriophage) emerge before, or soon after, the divergence of the prokaryotic and eukaryotic lineages. * 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


Statherian Period

* c. 1,800 Ma –
Statherian The Statherian Period (; grc, σταθερός, statherós, meaning "stable, firm") is the final geologic period in the Paleoproterozoic Era and lasted from Mya to Mya (million years ago). Instead of being based on stratigraphy, these dates a ...
Period starts.
Supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leav ...
Columbia forms, one of whose fragments being
Nena Gabriele Susanne Kerner (born 24 March 1960), better known as Nena, is a German singer and songwriter who rose to international fame in 1983 as the lead vocalist of the band Nena (band), Nena with the Neue Deutsche Welle song "99 Luftballons". I ...
. Oldest
erg The erg is a unit of energy equal to 10−7joules (100 nJ). It originated in the Centimetre–gram–second system of units (CGS). It has the symbol ''erg''. The erg is not an SI unit. Its name is derived from (), a Greek word meaning 'work' o ...
s develop on several cratons Barramundi Orogeny (c. 1.8 Gyr) influences MacArthur Basin in Northern Australia. * c. 1,780 Ma – Colorado Orogeny (1.781.65 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 Australiapossible 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 beltheavily sheared orthoclase porphyroclastic granites * c. 1,650 Ma – Kararan Orogeny (1.65 Gyr) uplifts great mountains on the Gawler Craton in Southern Australiaformation of Gawler Range including picturesque Conical Hill Track and "Organ Pipes" waterfall


Mesoproterozoic Era


Calymmian Period

* c. 1,600 Ma – Mesoproterozoic Era and
Calymmian The Calymmian Period (from grc, κάλυμμα, kálymma, meaning "cover") is the first geologic period in the Mesoproterozoic Era and lasted from Mya to Mya (million years ago). Instead of being based on stratigraphy, these dates are defined ...
Period start. Platform covers expand. Major orogenic event in Australia: Isan Orogeny influences Mount Isa Block of Queenslandmajor 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 The Vishnu Basement Rocks is the name recommended for all Early Proterozoic crystalline rocks (metamorphic and igneous) exposed in the Grand Canyon region. They form the crystalline basement rocks that underlie the Bass Limestone of the Unkar G ...
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 The Ectasian Period (from grc, ἔκτασις, éktasis, meaning "extension") is the second geologic period in the Mesoproterozoic Era and lasted from Mya ago to Mya (million years ago). Instead of being based on stratigraphy, these dates ...
Period starts. Platform covers expand. Major increase in
Stromatolite Stromatolites () or stromatoliths () are layered sedimentary formations ( microbialite) that are created mainly by photosynthetic microorganisms such as cyanobacteria, sulfate-reducing bacteria, and Pseudomonadota (formerly proteobacteria). T ...
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 Chinastabilization of
Amazonian Craton The Amazonian Craton is a geologic province located in South America. It occupies a large portion of the central, north and eastern part of the continent and represents one of Earth's largest cratonic regions. The Guiana Shield and Central Braz ...
in South America
Grenville orogeny The Grenville orogeny was a long-lived Mesoproterozoic mountain-building event associated with the assembly of the supercontinent Rodinia. Its record is a prominent orogenic belt which spans a significant portion of the North American continent, f ...
(to c. 1,000 Ma) in North America: globally associated with assembly of Supercontinent Rodinia establishes Grenville Province in Eastern North Americafolded mountains from Newfoundland to North Carolina as Old Rag Mountain forms * c. 1,270 Ma – Emplacement of Mackenzie granite mafic dike swarmone of three dozen dike swarms, forms into Mackenzie Large Igneous Provinceformation 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 The Stenian Period (, from grc, στενός, stenós, meaning "narrow") is the final geologic period in the Mesoproterozoic Era and lasted from Mya to Mya (million years ago). Instead of being based on stratigraphy, these dates are defined ...
Period starts.
Red alga Red algae, or Rhodophyta (, ; ), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority ...
'' Bangiomorpha pubescens'', earliest fossil evidence for
sex Sex is the trait that determines whether a sexually reproducing animal or plant produces male or female gametes. Male plants and animals produce smaller mobile gametes (spermatozoa, sperm, pollen), while females produce larger ones ( ova, of ...
ually reproducing
organism In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and ...
. Meiosis and sexual reproduction are present in single-celled eukaryotes, and possibly in the common ancestor of all eukaryotes. 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 formedsurrounded by superocean Mirovia * c. 1,100 Ma – First dinoflagellate evolve; photosynthetic, some develop
mixotroph A mixotroph is an organism that can use a mix of different sources of energy and carbon, instead of having a single trophic mode on the continuum from complete autotrophy at one end to heterotrophy at the other. It is estimated that mixotrophs comp ...
ic habits of ingesting prey. Thus, they become the first
predators Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
, forcing
acritarchs Acritarchs are organic microfossils, known from approximately 1800 million years ago to the present. The classification is a catch all term used to refer to any organic microfossils that cannot be assigned to other groups. Their diversity refle ...
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 plateleaves behind thick layers of rock that are exposed in Wisconsin, Minnesota, Iowa and Nebraska and creates rift valley where future
Lake Superior Lake Superior in central North America is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. and the third-largest by volume, holding 10% of the world's surface fresh wa ...
develops. * c. 1,080 Ma – Musgrave Orogeny (c. 1.080 Gyr) forms
Musgrave Block The Musgrave Block (also known as the Musgrave Province) is an east-west trending belt of Proterozoic granulite-gneiss basement rocks approximately long. The Musgrave Block extends from western South Australia into Western Australia. The Musgra ...
, an east–west trending belt of granulite-gneiss basement rocksvoluminous Kulgera Suite of granite and Birksgate Complex solidify * c. 1,076 Ma – Musgrave Orogeny: Warakurna large igneous province developsintrusion 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.


Neoproterozoic Era


Tonian Period

* c. 1,000 Ma – Neoproterozoic Era and
Tonian The Tonian (from grc, τόνος, tónos, meaning "stretch") is the first geologic period of the Neoproterozoic Era. It lasted from to Mya (million years ago). Instead of being based on stratigraphy, these dates are defined by the ICS based ...
Period start.
Grenville orogeny The Grenville orogeny was a long-lived Mesoproterozoic mountain-building event associated with the assembly of the supercontinent Rodinia. Its record is a prominent orogenic belt which spans a significant portion of the North American continent, f ...
ends. First radiation of dinoflagellates and spiny
acritarch Acritarchs are organic microfossils, known from approximately 1800 million years ago to the present. The classification is a catch all term used to refer to any organic microfossils that cannot be assigned to other groups. Their diversity refle ...
sincrease in defensive systems indicate that acritarchs are responding to carnivorous habits of dinoflagellatesdecline 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 Gyr900 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 Gascoynefolding and faulting of overlying Edmund and Collier basins * c. 920 Ma – Adelaide Geosyncline laid down in central Australiaessentially a rift complex, consists of thick layer of sedimentary rock and minor volcanics deposited on Easter marginlimestones, 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 algaefirst 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 otherformation of Adamastor Ocean. * c. 800 Ma – With free oxygen levels much higher,
carbon cycle The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. Carbon is the main component of biological compounds as well as a major componen ...
is disrupted and once again glaciation becomes severebeginning 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 plantsrise 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.


Cryogenian Period

* c. 720 Ma – Cryogenian Period starts, during which Earth freezes over ( Snowball Earth or Slushball Earth) at least 3 times. The
Sturtian The Sturtian glaciation was a Snowball Earth glaciation, or perhaps multiple glaciations, during the Cryogenian Period when the Earth experienced repeated large-scale glaciations. The duration of the Sturtian glaciation has been variously defined, ...
glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate be ...
continues the process begun during Kaigasgreat ice sheets cover most of the planet stunting evolutionary development of animal and plant lifesurvival based on small pockets of heat under the ice. * c. 700 Ma – Fossils of testate Amoeba first appear: first complex metazoans leave unconfirmed biomarkersthey introduce new complex body plan architecture which allows for development of complex internal and external structures.
Worm Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes (though not always). Worms vary in size from microscopic to over in length for marine polychaete wo ...
trail impressions in China: because putative "burrows" under stromatolite mounds are of uneven width and tapering makes biological origin difficult to defendstructures imply simple feeding behaviours. Rifting of Rodinia is completed: formation of new superocean of
Panthalassa Panthalassa, also known as the Panthalassic Ocean or Panthalassan Ocean (from Greek "all" and "sea"), was the superocean that surrounded the supercontinent Pangaea, the latest in a series of supercontinents in the history of Earth. During th ...
as previous Mirovia ocean bed closesMozambique 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 Armorica or Aremorica (Gaulish: ; br, Arvorig, ) is the name given in ancient times to the part of Gaul between the Seine and the Loire that includes the Brittany Peninsula, extending inland to an indeterminate point and down the Atlantic Coast ...
: involving one or more collisions of island arcs on margin of future Gondwana, terranes of Avalonia, Armorica and Ibera are laid down * c. 650 Ma – First
Demosponges Demosponges (Demospongiae) are the most diverse class in the phylum Porifera. They include 76.2% of all species of sponges with nearly 8,800 species worldwide (World Porifera Database). They are sponges with a soft body that covers a hard, ...
appear: form first skeletons of spicules made from protein
spongin Spongin, a modified type of collagen protein, forms the fibrous skeleton of most organisms among the phylum Porifera, the sponges. It is secreted by sponge cells known as spongocytes. Spongin gives a sponge its flexibility. True spongin is found ...
and silicabrightly 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 longerevidence 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 depositslast major orogenic event of Precambrian * c. 600 Ma –
Pan-African Orogeny 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 Oro ...
begins: Arabian-Nubian Shield formed between plates separating supercontinent fragments Gondwana and PannotiaSupercontinent 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 fossil A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, ...
s, e.g.,
worm Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes (though not always). Worms vary in size from microscopic to over in length for marine polychaete wo ...
burrows, and small
bilaterally symmetrical Symmetry in biology refers to the symmetry observed in organisms, including plants, animals, fungi, and bacteria. External symmetry can be easily seen by just looking at an organism. For example, take the face of a human being which has a pla ...
animals. Earliest
arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chiti ...
s. Earliest
fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
. * c. 558 Ma Dickinsonia, a large slow moving disc-like creature, first appearsthe 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 ''Kimberella'' is an extinct genus of bilaterian known only from rocks of the Ediacaran period. The slug-like organism fed by scratching the microbial surface on which it dwelt in a manner similar to the gastropods, although its affinity with t ...
appears. * c. 550 Ma – First possible comb-jellies, sponges, corals, and anemones. * c. 550 Ma
Uluru Uluru (; pjt, Uluṟu ), also known as Ayers Rock ( ) and officially gazetted as UluruAyers Rock, is a large sandstone formation in the centre of Australia. It is in the southern part of the Northern Territory, southwest of Alice Spring ...
or Ayers Rock begins forming during the
Petermann Orogeny The Petermann Orogeny was an Australian intracontinental event that affected basement rocks of the northern Musgrave Province and Ediacaran ( Proterozoic) sediments of the (now) southern Amadeus Basin between ~550-535 Ma. The remains are seen to ...
in Australia * c. 544 Ma – The
small shelly fauna The small shelly fauna, small shelly fossils (SSF), or early skeletal fossils (ESF) are mineralized fossils, many only a few millimetres long, with a nearly continuous record from the latest stages of the Ediacaran to the end of the Early Cambri ...
first appears.


Phanerozoic Eon


Paleozoic Era


Cambrian Period

* c. Ma – beginning of the Cambrian Period, the
Paleozoic Era The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ''z ...
and the current Phanerozoic Eon. End of the Ediacaran Period, the Proterozoic Eon and the Precambrian Supereon. The Ediacaran fauna disappears, while the Cambrian explosion initiates the emergence of most forms of complex life, including
vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...
s (
fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...
),
arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chiti ...
s,
echinoderm An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the s ...
s and
molluscs Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estim ...
. Pannotia breaks up into several smaller continents:
Laurentia 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, althoug ...
,
Baltica Baltica is a paleocontinent that formed in the Paleoproterozoic and now constitutes northwestern Eurasia, or Europe north of the Trans-European Suture Zone and west of the Ural Mountains. The thick core of Baltica, the East European Craton, ...
and Gondwana. * c. 530 Ma – First
fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...
– appearance of
Myllokunmingia ''Myllokunmingia'' is a genus of basal chordate from the Lower Cambrian Maotianshan shales of China 518 to 490 mya and is thought to be a vertebrate, although this is not conclusively proven. The species M. fengjiaoa is 28 mm long and 6&n ...
* c. 525 Ma – First
graptolite Graptolites are a group of colonial animals, members of the subclass Graptolithina within the class Pterobranchia. These filter-feeding organisms are known chiefly from fossils found from the Middle Cambrian ( Miaolingian, Wuliuan) through t ...
s. * c. Ma – First
trilobite Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the ...
s. * 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 ''Haikouella'' is an agnathan chordate from the Lower Cambrian Maotianshan Shales of Chengjiang County in Yunnan Province, China. An analysis in 2015 placed ''Haikouella'' as a junior synonym of ''Yunnanozoon,'' another Maotianshan shale Cambrian ...
,
Yunnanozoon ''Yunnanozoon lividum'' (Yunnan + Greek ζῷον ''zôion'', ''lividum''; "livid animal of Yunnan") is an extinct species of possible vertebrate or chordate from the Lower Cambrian, Chengjiang biota of Yunnan province, China. It is thought o ...
and early fish like
Haikouichthys ''Haikouichthys'' is an extinct genus of craniate (animals with notochords and distinct heads) that lived 518 million years ago, during the Cambrian explosion of multicellular life. ''Haikouichthys'' had a defined skull and other characteristi ...
. * c. 514 Ma –
Paradoxides ''Paradoxides'' is a genus of large to very large trilobite found throughout the world during the Middle Cambrian period. One record-breaking specimen of ''Paradoxides davidis'', described by John William Salter in 1863, is . The cephalon was s ...
trilobites appear, the largest members of the Cambrian Trilobites. * c. 511 Ma – Earliest
crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...
s. * c. 505 Ma – Deposition of the
Burgess Shale The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At old (middle Cambrian), it is one of the earliest fo ...
– Biota includes numerous strange invertebrates and arthropods like Opabinia; First great apex predator
Anomalocaris ''Anomalocaris'' ("unlike other shrimp", or "abnormal shrimp") is an extinct genus of radiodont, an order of early-diverging stem-group arthropods. The first fossils of ''Anomalocaris'' were discovered in the ''Ogygopsis'' Shale of the Stephen F ...
dominates. * c. 490 Ma – Beginning of the
Caledonian Orogeny The Caledonian orogeny was a mountain-building era recorded in the northern parts of the British Isles, the Scandinavian Mountains, Svalbard, eastern Greenland and parts of north-central Europe. The Caledonian orogeny encompasses events that ...
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. 488 Ma – Earliest
brittle star Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locomot ...
s.


Ordovician Period

* c. Ma – Beginning of the
Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. T ...
and the end of the Cambrian Period. * c. 485 Ma – First jawless fish – radiation of Thelodont fish into the Silurian * c. 460 Ma – First
crinoid Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are ...
s evolve. * c. 450 Ma – Late Ordovician microfossils of scales indicate the earliest evidence for the existence of jawed fish or
Gnathostomata Gnathostomata (; from Greek: (') "jaw" + (') "mouth") are the jawed vertebrates. Gnathostome diversity comprises roughly 60,000 species, which accounts for 99% of all living vertebrates, including humans. In addition to opposing jaws, living ...
. * c. 450 Ma –
Plants Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclude ...
and
arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chiti ...
s colonize the land.
Shark Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachi ...
s evolve. First
horseshoe crab Horseshoe crabs are marine and brackish water arthropods of the family Limulidae and the only living members of the order Xiphosura. Despite their name, they are not true crabs or crustaceans: they are chelicerates, most closely related to ar ...
s and starfish.


Silurian Period

* c. Ma – Beginning of the Silurian and the end of the
Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. T ...
Period. * c. 433 Ma –
Great Glen The Great Glen ( gd, An Gleann Mòr ), also known as Glen Albyn (from the Gaelic "Glen of Scotland" ) or Glen More (from the Gaelic ), is a glen in Scotland running for from Inverness on the edge of Moray Firth, in an approximately straight ...
Fault begins shaping the
Scottish Highlands The Highlands ( sco, the Hielands; gd, a’ Ghàidhealtachd , 'the place of the Gaels') is a historical region of Scotland. Culturally, the Highlands and the Lowlands diverged from the Late Middle Ages into the modern period, when Lowland S ...
as the Caledonian Orogeny reaches its close. * c. 430 Ma – First appearance of
Cooksonia ''Cooksonia'' is an extinct group of primitive land plants, treated as a genus, although probably not monophyletic. The earliest ''Cooksonia'' date from the middle of the Silurian (the Wenlock epoch); the group continued to be an important comp ...
the oldest known plant to have a stem with
vascular tissue Vascular tissue is a complex conducting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue are the xylem and phloem. These two tissues transport fluid and nutrients internally. The ...
and is thus a transitional form between the primitive non-vascular bryophytes and the
vascular plants Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They ...
* c. 420 Ma – First creature took a breath of air. First ray-finned fish and land scorpions. * c. 410 Ma – First toothed fish and
nautiloid Nautiloids are a group of marine cephalopods (Mollusca) which originated in the Late Cambrian and are represented today by the living ''Nautilus'' and '' Allonautilus''. Fossil nautiloids are diverse and speciose, with over 2,500 recorded specie ...
s.


Devonian Period

* c. Ma – Beginning of the Devonian and end of the Silurian Period. First
insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...
s. * c. 419 Ma –
Old Red Sandstone The Old Red Sandstone is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the northeastern seaboard of North America. It also exte ...
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 ''Cephalaspis'' (from el, κεφαλή , 'head' and el, ἀσπίς , 'shield') is a possibly monotypic genus of extinct osteostracan agnathan vertebrate. It was a trout-sized detritivorous fish that lived in the early Devonian. Description ...
, an iconic member of the
Osteostraci The class Osteostraci (meaning "bony shells") is an extinct taxon of bony-armored jawless fish, termed "ostracoderms", that lived in what is now North America, Europe and Russia from the Middle Silurian to Late Devonian. Anatomically speaking, t ...
, appears, the most advanced of the jawless fish. Its boney armor serves as protection against the successful radiation of
Placoderms Placodermi (from Greek πλάξ 'plate' and δέρμα 'skin', literally 'plate-skinned') is a class of armoured prehistoric fish, known from fossils, which lived from the Silurian to the end of the Devonian period. Their head and thorax were ...
and as a way to live in calcium-poor fresh water environments. * c. 395 Ma – First of many modern groups, including
tetrapod Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids ( pelycosaurs, extinct t ...
s. * c. 375 Ma – Acadian Orogeny begins influencing mountain building along the Atlantic seaboard of North America. * c. 370 Ma –
Cladoselache ''Cladoselache'' is an Extinction, extinct genus of shark-like chondrichthyan (cartilaginous fish) from the Late Devonian (Famennian) of North America. It was similar in body shape to modern Lamnidae, lamnid sharks (such as Isurus, mako sharks and ...
, 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
fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes exce ...
s. The large predatory lobe-finned fish
Hyneria ''Hyneria'' is a genus of large prehistoric predatory lobe-finned fish which lived in freshwater during the Devonian period around 360 million years ago. Etymology The genus name ''Hyneria'' is a reference to the village of Hyner, Pennsylvan ...
evolves. * c. 350 Ma – First large sharks,
ratfish Chimaeras are cartilaginous fish in the order Chimaeriformes , known informally as ghost sharks, rat fish, spookfish, or rabbit fish; the last three names are not to be confused with rattails, Opisthoproctidae, or Siganidae, respectively. At o ...
and
hagfish Hagfish, of the class Myxini (also known as Hyperotreti) and order Myxiniformes , are eel-shaped, slime-producing marine fish (occasionally called slime eels). They are the only known living animals that have a skull but no vertebral column, ...
.


Carboniferous Period

* c. Ma – Beginning of the Carboniferous and the end of
Devonian Period The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, w ...
. Amphibians diversify. * c. 345 Ma –
Agaricocrinus americanus ''Agaricocrinus americanus'', the mushroom crinoid, is a species of Extinction, extinct crinoid, known only from its fossils, which are found in the U.S. states of Indiana, Tennessee and Kentucky. They date back to the Mississippian age, Lower M ...
a representative of the
Crinoids Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are ...
appears as part of a successful radiation of the echinoderms. * c. 330 Ma – First amniotes evolve. * c. 320 Ma – First
synapsid Synapsids + (, 'arch') > () "having a fused arch"; synonymous with ''theropsids'' (Greek, "beast-face") are one of the two major groups of animals that evolved from basal amniotes, the other being the sauropsids, the group that includes reptil ...
s evolve. * c. 318 Ma – First
beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
s. * c. 315 Ma – The evolution of the first reptiles. * c. 312 Ma –
Hylonomus ''Hylonomus'' (; ''hylo-'' "forest" + ''nomos'' "dweller") is an extinct genus of reptile that lived 312 million years ago during the Late Carboniferous period. It is the earliest unquestionable reptile (''Westlothiana'' is older, but in fact it ...
makes first appearance, one of the oldest reptiles found in the fossil record. * c. 306 Ma –
Diplocaulus ''Diplocaulus'' (meaning "double caul") is an extinct genus of lepospondyl amphibians which lived from the Late Carboniferous to the Late Permian of North America and Africa. ''Diplocaulus'' is by far the largest and best-known of the lepospond ...
evolves in the swamps with an unusual boomerang-like skull. * c. 305 Ma – First
diapsid Diapsids ("two arches") are a clade of sauropsids, distinguished from more primitive eureptiles by the presence of two holes, known as temporal fenestrae, in each side of their skulls. The group first appeared about three hundred million years a ...
s evolve;
Meganeura ''Meganeura'' is a genus of extinct insects from the Late Carboniferous (approximately 300 million years ago). They resembled and are related to the present-day dragonflies and damselflies, and were predatory, with their diet mainly consisting o ...
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 Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 million y ...
– the
Ural mountains The Ural Mountains ( ; rus, Ура́льские го́ры, r=Uralskiye gory, p=ʊˈralʲskʲɪjə ˈɡorɨ; ba, Урал тауҙары) or simply the Urals, are a mountain range that runs approximately from north to south through western ...
are uplifted


Permian Period

* c. Ma – End of Carboniferous and beginning of Permian Period. By this time, all continents have fused into the
supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leav ...
of
Pangaea Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 million y ...
.
Seed plant A spermatophyte (; ), also known as phanerogam (taxon Phanerogamae) or phaenogam (taxon Phaenogamae), is any plant that produces seeds, hence the alternative name seed plant. Spermatophytes are a subset of the embryophytes or land plants. They inc ...
s and conifers diversify along with
temnospondyl Temnospondyli (from Greek τέμνειν, ''temnein'' 'to cut' and σπόνδυλος, ''spondylos'' 'vertebra') is a diverse order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carbo ...
s and
pelycosaur Pelycosaur ( ) is an older term for basal or primitive Late Paleozoic synapsids, excluding the therapsids and their descendants. Previously, the term ''mammal-like reptile'' had been used, and pelycosaur was considered an order, but this is ...
s. * c. 296 Ma – Oldest known octopus fossil. * c. 295 Ma – Dimetrodon evolves. * c. 280 Ma – First
cycad Cycads are seed plants that typically have a stout and woody (ligneous) trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male o ...
s evolve. * c. 275 Ma – First
therapsid Therapsida is a major group of eupelycosaurian synapsids that includes mammals, their ancestors and relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more ...
s evolve. * c. 270 Ma –
Gorgonopsia Gorgonopsia (from the Greek Gorgon, a mythological beast, and 'aspect') is an extinct clade of sabre-toothed therapsids from the Middle to Upper Permian roughly 265 to 252 million years ago. They are characterised by a long and narrow skull, a ...
ns, the apex predators of the Late Permian, first evolve. * c. 251.4 Ma – Permian mass extinction. End of
Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last ...
Period and of the Palaeozoic Era. Beginning of
Triassic The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...
Period, the Mesozoic era and of the age of the dinosaurs.


Mesozoic Era


Triassic Period

* c. Ma – Mesozoic era and
Triassic Period The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...
begin. Mesozoic Marine Revolution begins. * c. 245 Ma – First ichthyosaurs. * c. 240 Ma – Cynodonts and
rhynchosaur Rhynchosaurs are a group of extinct herbivorous Triassic archosauromorph reptiles, belonging to the order Rhynchosauria. Members of the group are distinguished by their triangular skulls and elongated, beak like premaxillary bones. Rhynchosaurs ...
s diversify. * c. 225 Ma – First
dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
s and teleosti evolve. * c. 220 Ma – First
crocodilia Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest livi ...
ns and
flies Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced m ...
. * c. 215 Ma – First
turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked t ...
s. Long-necked sauropod dinosaurs and ''
Coelophysis ''Coelophysis'' ( traditionally; or , as heard more commonly in recent decades) is an extinct genus of coelophysid theropod dinosaur that lived approximately 228 to 201.3 million years ago during the latter part of the Triassic Period fro ...
'', one of the earliest
theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...
dinosaurs, evolve. First mammals. * c. 214 Ma -
Plateosaurus ''Plateosaurus'' (probably meaning "broad lizard", often mistranslated as "flat lizard") is a genus of plateosaurid dinosaur that lived during the Late Triassic period, around 214 to 204 million years ago, in what is now Central and Northern Eur ...
, a basal sauropodomorph or so-called “prosauropod” evolves in what is now Central and Northern Europe, Greenland and North America * c. 210 Ma – Earliest elasmosauridae.


Jurassic Period

* c. Ma – Triassic-Jurassic extinction event marks the end of Triassic and beginning of
Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...
Period. The largest dinosaurs, such as ''
Diplodocus ''Diplodocus'' (, , or ) was a genus of diplodocid sauropod dinosaurs, whose fossils were first discovered in 1877 by S. W. Williston. The generic name, coined by Othniel Charles Marsh in 1878, is a neo-Latin term derived from Greek δι ...
'' and ''
Brachiosaurus ''Brachiosaurus'' () is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about 154to 150million years ago. It was first described by American paleontologist Elmer S. Riggs in 1903 from fossils found in th ...
'' evolve during this time, as do the
carnosaurs Carnosauria is an extinct large group of predatory dinosaurs that lived during the Jurassic and Cretaceous periods. Starting from the 1990s, scientists have discovered some very large carnosaurs in the carcharodontosaurid family, such as ''Gi ...
; large, bipedal predatory dinosaurs such as ''
Allosaurus ''Allosaurus'' () is a genus of large carnosaurian theropod dinosaur that lived 155 to 145 million years ago during the Late Jurassic epoch ( Kimmeridgian to late Tithonian). The name "''Allosaurus''" means "different lizard" alludin ...
''. First specialized
pterosaur Pterosaurs (; from Greek ''pteron'' and ''sauros'', meaning "wing lizard") is an extinct clade of flying reptiles in the order, Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 ...
s and sauropods.
Ornithischian Ornithischia () is an extinct order of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek st ...
s diversify. * c. 199 Ma – First
squamata Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest order of reptiles, comprising lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. With over 10,900 species ...
evolve. Earliest lizards. * c. 190 Ma –
Pliosaur Pliosauroidea is an extinct clade of plesiosaurs, known from the earliest Jurassic to early Late Cretaceous. They are best known for the subclade Thalassophonea, which contained crocodile-like short-necked forms with large heads and massive toot ...
s evolve, along with many groups of primitive sea invertebrates. * c. 180 Ma –
Pangaea Pangaea or Pangea () was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous approximately 335 million y ...
splits into two major continents: Laurasia in the north and Gondwana in the south. * c. 176 Ma – First stegosaurs. * c. 170 Ma – First
salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...
s and
newt A newt is a salamander in the subfamily Pleurodelinae. The terrestrial juvenile phase is called an eft. Unlike other members of the family Salamandridae, newts are semiaquatic, alternating between aquatic and terrestrial habitats. Not all aqua ...
s evolve. Cynodonts go extinct. * c. 165 Ma – First
rays Ray may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), a bony or horny spine on a fin Science and mathematics * Ray (geometry), half of a line proceeding from an initial point * Ray (gra ...
and glycymeridid bivalves. * c. 164 Ma – The first gliding mammal,
volaticotherium ''Volaticotherium antiquum'' (meaning "ancient gliding beast") is an extinct, gliding, insectivorous mammal that lived in Asia during the Jurassic period, around 164 mya. It is the only member of the genus ''Volaticotherium''. The discovery of ...
, appears in the fossil record. * c. 161 Ma – First
ceratopsian Ceratopsia or Ceratopia ( or ; Greek: "horned faces") is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic ...
s. * c. 155 Ma – First
bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s and
triconodont Eutriconodonta is an order of early mammals. Eutriconodonts existed in Asia, Africa, Europe, North and South America during the Jurassic and the Cretaceous periods. The order was named by Kermack ''et al.'' in 1973 as a replacement name for the p ...
s. Stegosaurs and
theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...
s diversify. * c. 153 Ma – Earliest
pine trees A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garde ...
.


Cretaceous Period

* c. Ma – End of
Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...
and beginning of
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
Period. * c. 145 Ma – First
mantis Mantises are an order (Mantodea) of insects that contains over 2,400 species in about 460 genera in 33 families. The largest family is the Mantidae ("mantids"). Mantises are distributed worldwide in temperate and tropical habitats. They ha ...
es. * c. 140 Ma – Earliest
orb-weaver spider Orb-weaver spiders are members of the spider family (biology), family Araneidae. They are the most common group of builders of spiral wheel-shaped spider web, webs often found in gardens, fields, and forests. The English word "orb" can mean "circ ...
s evolve. * c. 130 Ma – Laurasia and Gondwana begin to split apart as the
Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
forms. First
flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
s. Earliest anglerfish. * c. 125 Ma –
Sinodelphys ''Sinodelphys'' is an extinct eutherian from the Early Cretaceous, estimated to be 125 million years old. It was discovered and described in 2003 in rocks of the Yixian Formation in Liaoning Province, China, by a team of scientists including Zhe ...
szalayi, the earliest known marsupial, evolves in China. * c. 122 Ma – Earliest
ankylosauridae Ankylosauridae () is a family of armored dinosaurs within Ankylosauria, and is the sister group to Nodosauridae. The oldest known Ankylosaurids date to around 122 million years ago and went extinct 66 million years ago during the Cretaceous–Pa ...
. * c. 115 Ma – First monotremes. * c. 110 Ma – First
hesperornithes Hesperornithes is an extinct and highly specialized group of aquatic avialans closely related to the ancestors of modern birds. They inhabited both marine and freshwater habitats in the Northern Hemisphere, and include genera such as '' Hesperorn ...
. * c. 106 Ma –
Spinosaurus ''Spinosaurus'' (; ) is a genus of spinosaurid dinosaur that lived in what now is North Africa during the Cenomanian to upper Turonian stages of the Late Cretaceous period, about 99 to 93.5 million years ago. The genus was known first f ...
evolves. * c. 100 Ma – First bees. * c. 94 Ma – First modern species of palm trees appear. * c. 90 Ma – the
Indian subcontinent The Indian subcontinent is a list of the physiographic regions of the world, physiographical region in United Nations geoscheme for Asia#Southern Asia, Southern Asia. It is situated on the Indian Plate, projecting southwards into the Indian O ...
splits from Gondwana, becoming an island
continent A continent is any of several large landmasses. Generally identified by convention rather than any strict criteria, up to seven geographical regions In geography, regions, otherwise referred to as zones, lands or territories, are areas t ...
. Ichthyosaurs go extinct.
Snake Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more j ...
s and
tick Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...
s evolve. * c. 86 Ma – First hadrosauridae. * c. 80 Ma – Australia splits from
Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest cont ...
. First
ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of ...
s. * c. 75 Ma – First
velociraptor ''Velociraptor'' (; ) is a genus of small dromaeosaurid dinosaur that lived in Asia during the Late Cretaceous epoch, about 75 million to 71 million years ago. Two species are currently recognized, although others have been assigned in the p ...
s. * c. 70 Ma –
Multituberculate Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the Middle Jurassic, a ...
s diversify. The Mosasaurus evolves. * c. 68 Ma –
Tyrannosaurus rex ''Tyrannosaurus'' is a genus of large theropod dinosaur. The species ''Tyrannosaurus rex'' (''rex'' meaning "king" in Latin), often called ''T. rex'' or colloquially ''T-Rex'', is one of the best represented theropods. ''Tyrannosaurus'' live ...
evolves. Earliest species of
Triceratops ''Triceratops'' ( ; ) is a genus of herbivorous chasmosaurine ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the Late Cretaceous period, about 68 million years ago in what is now North America. It is one ...
. Quetzalcoatlus, one of the largest flying animals to ever live, first appears in the fossil record. * c. .038 ± 0.011 Ma – Cretaceous-Paleogene extinction event at the end of the
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
Period marks the end of the
Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...
era and the age of the dinosaurs; start of the Paleogene Period and the current Cenozoic era.


Cenozoic Era


Paleogene Period

* c. 63 Ma – First
creodont Creodonta ("meat teeth") is a former order of extinct carnivorous placental mammals that lived from the early Paleocene to the late Miocene epochs in North America, Europe, Asia and Africa. Originally thought to be a single group of animals ance ...
s. * c. 62 Ma – First penguins. * c. 60 Ma – Evolution of the first primates and miacids. Flightless birds diversify. * c. 56 Ma –
Gastornis ''Gastornis'' is an extinct genus of large flightless birds that lived during the mid Paleocene to mid Eocene epochs of the Paleogene period. Fossils have been found in Europe, Asia and North America, with the remains from North America or ...
evolves. * c. 55 Ma – the island of the
Indian subcontinent The Indian subcontinent is a list of the physiographic regions of the world, physiographical region in United Nations geoscheme for Asia#Southern Asia, Southern Asia. It is situated on the Indian Plate, projecting southwards into the Indian O ...
collides with Asia, thrusting up the
Himalayas The Himalayas, or Himalaya (; ; ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the very highest, Mount Everest. Over 10 ...
and the
Tibetan Plateau The Tibetan Plateau (, also known as the Qinghai–Tibet Plateau or the Qing–Zang Plateau () or as the Himalayan Plateau in India, is a vast elevated plateau located at the intersection of Central, South and East Asia covering most of the ...
. Many modern bird groups appear. First
whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...
ancestors. First
rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are n ...
s,
lagomorph The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two living families: the Leporidae (hares and rabbits) and the Ochotonidae (pikas). The name of the order is derived from the Ancient Greek ''lagos'' (λαγ ...
s, armadillos,
sirenian The Sirenia (), commonly referred to as sea-cows or sirenians, are an order of fully aquatic, herbivorous mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters. The Sirenia currently comprise two distinct f ...
s,
proboscidean The Proboscidea (; , ) are a taxonomic order of afrotherian mammals containing one living family (Elephantidae) and several extinct families. First described by J. Illiger in 1811, it encompasses the elephants and their close relatives. From ...
s,
perissodactyl Odd-toed ungulates, mammals which constitute the taxonomic order Perissodactyla (, ), are animals—ungulates—who have reduced the weight-bearing toes to three (rhinoceroses and tapirs, with tapirs still using four toes on the front legs) o ...
s,
artiodactyl The even-toed ungulates (Artiodactyla , ) are ungulates—hoofed animals—which bear weight equally on two (an even number) of their five toes: the third and fourth. The other three toes are either present, absent, vestigial, or pointing poster ...
s, and mako sharks. Angiosperms diversify. * c. 52.5 Ma – First
passerine A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped'), which includes more than half of all bird species. Sometimes known as perching birds, passerines are distinguished from other orders of birds by th ...
(perching) birds. * c. 52 Ma – First
bat Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most ...
s. * c. 50 Ma – Africa collides with
Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago ...
, closing the
Tethys Sea The Tethys Ocean ( el, Τηθύς ''Tēthús''), also called the Tethys Sea or the Neo-Tethys, was a prehistoric ocean that covered most of the Earth during much of the Mesozoic Era and early Cenozoic Era, located between the ancient continents ...
. Divergence of
cat The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...
and
dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. Do ...
ancestors. Primates diversify.
Brontothere Brontotheriidae is a family (biology), family of extinct mammals belonging to the order Perissodactyla, the order that includes horses, rhinoceroses, and tapirs. Superficially, they looked rather like Rhinoceros, rhinos, although they were actua ...
s,
tapir Tapirs ( ) are large, herbivorous mammals belonging to the family Tapiridae. They are similar in shape to a pig, with a short, prehensile nose trunk. Tapirs inhabit jungle and forest regions of South and Central America, with one species inh ...
s, and
rhino A rhinoceros (; ; ), commonly abbreviated to rhino, is a member of any of the five extant species (or numerous extinct species) of odd-toed ungulates in the family Rhinocerotidae. (It can also refer to a member of any of the extinct species o ...
s evolve. * c. 49 Ma –
Whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...
s return to the water. * c. 45 Ma – Camels evolve in North America. * c. 40 Ma – Age of the
Catarrhini The parvorder Catarrhini , catarrhine monkeys, Old World anthropoids, or Old World monkeys, consisting of the Cercopithecoidea and apes (Hominoidea). In 1812, Geoffroy grouped those two groups together and established the name Catarrhini, "Old ...
parvorder; first
canines Canine may refer to: Zoology and anatomy * a dog-like Canid animal in the subfamily Caninae ** ''Canis'', a genus including dogs, wolves, coyotes, and jackals ** Dog, the domestic dog * Canine tooth, in mammalian oral anatomy People with the surn ...
evolve. Lepidopteran insects become recognizable.
Gastornis ''Gastornis'' is an extinct genus of large flightless birds that lived during the mid Paleocene to mid Eocene epochs of the Paleogene period. Fossils have been found in Europe, Asia and North America, with the remains from North America or ...
goes extinct.
Basilosaurus ''Basilosaurus'' (meaning "king lizard") is a genus of large, predatory, prehistoric archaeocete whale from the late Eocene, approximately 41.3 to 33.9 million years ago (mya). First described in 1834, it was the first archaeocete and prehistor ...
evolves. * c. 37 Ma – First
Nimravid Nimravidae is an extinct family of carnivorans, sometimes known as false saber-toothed cats, whose fossils are found in North America and Eurasia. Not considered to belong to the true cats (family Felidae), the nimravids are generally considered ...
s. * c. Ma – End of
Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...
, start of Oligocene epoch. * c. 35 Ma –
Grassland A grassland is an area where the vegetation is dominated by grasses ( Poaceae). However, sedge ( Cyperaceae) and rush ( Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur na ...
s first appear. Glyptodonts, ground sloths, peccaries, dogs, eagles, and hawks evolve. * c. 33 Ma – First thylacinid marsupials evolve. * c. 30 Ma –
Brontothere Brontotheriidae is a family (biology), family of extinct mammals belonging to the order Perissodactyla, the order that includes horses, rhinoceroses, and tapirs. Superficially, they looked rather like Rhinoceros, rhinos, although they were actua ...
s go extinct. Pigs evolve.
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...
separates from Antarctica, becoming an island continent. * c. 28 Ma –
Paraceratherium ''Paraceratherium'' is an extinct genus of hornless rhinoceros. It is one of the largest terrestrial mammals that has existed and lived from the early to late Oligocene epoch (34–23 million years ago). The first fossils were discovered ...
evolves. First pelicans. * c. 26 Ma – Emergence of the first true elephants. * c. 25 Ma – First deer.
Cat The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...
s evolve. * c. 24 Ma – Earliest
pinniped Pinnipeds (pronounced ), commonly known as seals, are a widely range (biology), distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammal, marine mammals. They comprise the extant taxon, extant family (biology ...
s (seals).


Neogene Period

* c. Ma – Neogene Period and
Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
epoch begin * c. 22 Ma – First hyenas. * c. 20 Ma – Giraffes and
giant anteater The giant anteater (''Myrmecophaga tridactyla'') is an insectivorous mammal native to Central and South America. It is one of four living species of anteaters, of which it is the largest member. The only extant member of the genus ''Myrmecophag ...
s evolve. * c. 18–12 Ma – estimated age of the '' Hominidae''/'' Hylobatidae'' (great apes vs. gibbons) split. * c. 16 Ma – The
hippopotamus The hippopotamus ( ; : hippopotamuses or hippopotami; ''Hippopotamus amphibius''), also called the hippo, common hippopotamus, or river hippopotamus, is a large semiaquatic mammal native to sub-Saharan Africa. It is one of only two extan ...
evolves. * c. 15 Ma – First
mastodon A mastodon ( 'breast' + 'tooth') is any proboscidean belonging to the extinct genus ''Mammut'' (family Mammutidae). Mastodons inhabited North and Central America during the late Miocene or late Pliocene up to their extinction at the end of th ...
s,
bovid The Bovidae comprise the biological family of cloven-hoofed, ruminant mammals that includes cattle, bison, buffalo, antelopes, and caprines. A member of this family is called a bovid. With 143 extant species and 300 known extinct species, ...
s, and kangaroos. Australian megafauna diversify. * c. 11 Ma – Estimated date for the origin of the modern
Yangtze The Yangtze or Yangzi ( or ; ) is the longest river in Asia, the third-longest in the world, and the longest in the world to flow entirely within one country. It rises at Jari Hill in the Tanggula Mountains (Tibetan Plateau) and flows ...
river. * c. 10 Ma – Insects diversify. First large horses. Camels cross from America to Asia. * c. 6.5 Ma – First members of the Hominini tribe. * c. 6 Ma –
Australopithecine Australopithecina or Hominina is a subtribe in the tribe Hominini. The members of the subtribe are generally ''Australopithecus'' (cladistically including the genera ''Homo'', '' Paranthropus'', and ''Kenyanthropus''), and it typically includ ...
s diversify. * c. 5.96–5.33 Ma –
Messinian Salinity Crisis The Messinian salinity crisis (MSC), also referred to as the Messinian event, and in its latest stage as the Lago Mare event, was a geological event during which the Mediterranean Sea went into a cycle of partial or nearly complete desiccation (d ...
: the precursor of the current Strait of Gibraltar closes repeatedly, leading to a partial desiccation and strong increase in salinity of the
Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...
. * c. 5.4–6.3 Ma – Estimated age of the ''
Homo ''Homo'' () is the genus that emerged in the (otherwise extinct) genus '' Australopithecus'' that encompasses the extant species ''Homo sapiens'' ( modern humans), plus several extinct species classified as either ancestral to or closely relat ...
/ Pan'' (human vs. chimpanzee)
split Split(s) or The Split may refer to: Places * Split, Croatia, the largest coastal city in Croatia * Split Island, Canada, an island in the Hudson Bay * Split Island, Falkland Islands * Split Island, Fiji, better known as Hạfliua Arts, entertai ...
. * c. 5.5 Ma – Appearance of the genus ''
Ardipithecus ''Ardipithecus'' is a genus of an extinct hominine that lived during the Late Miocene and Early Pliocene epochs in the Afar Depression, Ethiopia. Originally described as one of the earliest ancestors of humans after they diverged from the chimp ...
'' * 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 Aswan (, also ; ar, أسوان, ʾAswān ; cop, Ⲥⲟⲩⲁⲛ ) is a city in Southern Egypt, and is the capital of the Aswan Governorate. Aswan is a busy market and tourist centre located just north of the Aswan Dam on the east bank of the ...
. The modern
Nile The Nile, , Bohairic , lg, Kiira , Nobiin: Áman Dawū is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered the longest ...
starts filling this sea branch with sediments, slowly creating the Nile Valley. * c. Ma –
Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Nimravid Nimravidae is an extinct family of carnivorans, sometimes known as false saber-toothed cats, whose fossils are found in North America and Eurasia. Not considered to belong to the true cats (family Felidae), the nimravids are generally considered ...
s go extinct. * c. 5.0 Ma – The Colorado Plateau reaches its present height, and the course of the
Colorado River The Colorado River ( es, Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and northern Mexico. The river drains an expansive, arid watershed that encompasses parts of seven U.S. s ...
becomes close to the present one. * c. 4.8 Ma – The
mammoth A mammoth is any species of the extinct elephantid genus ''Mammuthus'', one of the many genera that make up the order of trunked mammals called proboscideans. The various species of mammoth were commonly equipped with long, curved tusks an ...
appears. * c. 4.2 Ma – appearance of the genus ''
Australopithecus ''Australopithecus'' (, ; ) is a genus of early hominins that existed in Africa during the Late Pliocene and Early Pleistocene. The genus ''Homo'' (which includes modern humans) emerged within ''Australopithecus'', as sister to e.g. ''Austral ...
'' * c. 4 Ma – First
zebra Zebras (, ) (subgenus ''Hippotigris'') are African equines with distinctive black-and-white striped coats. There are three living species: the Grévy's zebra (''Equus grevyi''), plains zebra (''E. quagga''), and the mountain zebra (''E. zebr ...
s. * c. 3 Ma – Isthmus of Panama joins North and South America. Great American Interchange.
Cat The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...
s,
condor Condor is the common name for two species of New World vultures, each in a monotypic genus. The name derives from the Quechua ''kuntur''. They are the largest flying land birds in the Western Hemisphere. They are: * The Andean condor (''Vu ...
s,
raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the common raccoon to distinguish it from other species, is a mammal native to North America. It is the largest of the procyonid family, having a body length of , and a body weight of ...
s and
camelid Camelids are members of the biological family Camelidae, the only currently living family in the suborder Tylopoda. The seven extant members of this group are: dromedary camels, Bactrian camels, wild Bactrian camels, llamas, alpacas, vicuñas, ...
s move south; armadillos, hummingbirds, and opossums move north. * c. 2.7 Ma – Paranthropus evolves. * c. 2.6 Ma – The current
ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gre ...
begins.


Quaternary Period

* c. Ma – start of the
Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...
epoch, the Stone Age and the current Quaternary Period; emergence of the genus ''
Homo ''Homo'' () is the genus that emerged in the (otherwise extinct) genus '' Australopithecus'' that encompasses the extant species ''Homo sapiens'' ( modern humans), plus several extinct species classified as either ancestral to or closely relat ...
''.
Smilodon ''Smilodon'' is a genus of the extinct machairodont subfamily of the felids. It is one of the most famous prehistoric mammals and the best known saber-toothed cat. Although commonly known as the saber-toothed tiger, it was not closely rela ...
, the best known of the sabre-toothed cats, appears. * c. 2.4 Ma – The Amazon River takes its present shape in South America. * c. 2.0–1.5 Ma – The basin of the
Congo River The Congo River ( kg, Nzâdi Kôngo, french: Fleuve Congo, pt, Rio Congo), formerly also known as the Zaire River, is the second longest river in Africa, shorter only than the Nile, as well as the second largest river in the world by discharge ...
acquires its present shape. * c. 1.9 Ma – Oldest known '' Homo erectus'' fossils. This species might be evolved some time before, up to c. 2 Ma ago. * c. 1.7 Ma –
Australopithecine Australopithecina or Hominina is a subtribe in the tribe Hominini. The members of the subtribe are generally ''Australopithecus'' (cladistically including the genera ''Homo'', '' Paranthropus'', and ''Kenyanthropus''), and it typically includ ...
s go extinct. * c. 1.8–0.8 Ma – colonisation of Eurasia by '' Homo erectus''. * c. 1.5 Ma – earliest possible evidence of the controlled use of
fire Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction products. At a certain point in the combustion reaction, called the ignition point, flames a ...
by '' Homo erectus'' * c. 1.2 Ma –
Homo antecessor ''Homo antecessor'' (Latin "pioneer man") is an extinct species of archaic human recorded in the Spanish Sierra de Atapuerca, a productive archaeological site, from 1.2 to 0.8 million years ago during the Early Pleistocene. Populations of this ...
evolves. Paranthropus dies out. * c. 0.79 Ma – earliest demonstrable evidence of the controlled use of
fire Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction products. At a certain point in the combustion reaction, called the ignition point, flames a ...
by '' Homo erectus'' * c. 0.7 Ma – last reversal of the
earth's magnetic field Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic ...
* 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. * c. 0.64 Ma – Yellowstone caldera erupts * c. 0.6 Ma –
Homo heidelbergensis ''Homo heidelbergensis'' (also ''H. sapiens heidelbergensis''), sometimes called Heidelbergs, is an extinct species or subspecies of archaic human which existed during the Middle Pleistocene. It was subsumed as a subspecies of '' H. erectus'' i ...
evolves. * c. 0.5 Ma – First
brown bear The brown bear (''Ursus arctos'') is a large bear species found across Eurasia and North America. In North America, the populations of brown bears are called grizzly bears, while the subspecies that inhabits the Kodiak Islands of Alaska is ...
s. * c. 0.315 Ma – Middle Paleolithic begins. Appearance of ''
Homo sapiens Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
'' in
Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...


Etymology of period names


Visual summary


See also

*
Astronomical chronology Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest ...
** Age of the Earth **
Age of the universe In physical cosmology, the age of the universe is the time elapsed since the Big Bang. Astronomers have derived two different measurements of the age of the universe: a measurement based on direct observations of an early state of the universe, ...
*
Chronological dating Chronological dating, or simply dating, is the process of attributing to an object or event a date in the past, allowing such object or event to be located in a previously established chronology. This usually requires what is commonly known as a "d ...
, archaeological chronology **
Absolute dating Absolute dating is the process of determining an age on a specified chronology in archaeology and geology. Some scientists prefer the terms chronometric or calendar dating, as use of the word "absolute" implies an unwarranted certainty of accuracy ...
**
Relative dating Relative dating is the science of determining the relative order of past events (i.e., the age of an object in comparison to another), without necessarily determining their absolute age (i.e., estimated age). In geology, rock or superficial dep ...
**
Phase (archaeology) In archaeology, a phase refers to the logical reduction of contexts recorded during excavation to nearly contemporary archaeological horizons that represent a distinct "phase" of previous land use. These often but not always will be a representati ...
**
Archaeological association This page is a glossary of archaeology, the study of the human past from material remains. A B C D E F ...
*
Geochronology Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is ...
** Future of the Earth **
Geologic time scale The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochr ...
**
Geological history of Earth Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ea ...
**
Plate reconstruction :''This article describes techniques; for a history of the movement of tectonic plates, see Geological history of Earth.'' Plate reconstruction is the process of reconstructing the positions of tectonic plates relative to each other (relative moti ...
**
Plate tectonics Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large ...
** Thermochronology ** Timeline of natural history ***
Detailed logarithmic timeline This timeline shows the whole history of the universe, the Earth, and mankind in one table. Each row is defined in ''years ago'', that is, years before the present date, with the earliest times at the top of the chart. In each table cell on the r ...
*** Terasecond and longer ***
Timeline of the far future While the future cannot be predicted with certainty, present understanding in various scientific fields allows for the prediction of some far-future events, if only in the broadest outline. These fields include astrophysics, which studies how ...
**
List of geochronologic names This is a list of official and unofficial names for time spans in the geologic timescale and units of chronostratigraphy. Since many of the smallest subdivisions of the geologic timescale were in the past defined on regional lithostratigraphic unit ...
* General **
Consilience In science and history, consilience (also convergence of evidence or concordance of evidence) is the principle that evidence from independent, unrelated sources can "converge" on strong conclusions. That is, when multiple sources of evidence are ...
, evidence from independent, unrelated sources can "converge" on strong conclusions


References

{{reflist, 30em


External links


Art of the Nature Timelines on Wikipedia
Natural history Natural history
Natural Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...
Mass extinction timelines * natural history