fbpx
Wikipedia

Geologic time scale

October 19, 2023

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 geochronology (a scientific branch of geology that aims to determine the age of rocks). It is used primarily by Earth scientists (including geologists, paleontologists, geophysicists, geochemists, and paleoclimatologists) to describe the timing and relationships of events in geologic history. The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as lithologies, paleomagnetic properties, and fossils. The definition of standardised international units of geologic time is the responsibility of the International Commission on Stratigraphy (ICS), a constituent body of the International Union of Geological Sciences (IUGS), whose primary objective[1] is to precisely define global chronostratigraphic units of the International Chronostratigraphic Chart (ICC)[2] that are used to define divisions of geologic time. The chronostratigraphic divisions are in turn used to define geochronologic units.[2]

Geologic time scale with proportional representation of eons/eonothems and eras/erathems. Cenozoic is abbreviated to Cz. The image also shows some notable events in Earth's history and the general evolution of life. A megannus (Ma) represents one million (106) years.
Alternate representation of the geologic time scale represented as a clock. Note: the GTS is linear and not cyclic.

While some regional terms are still in use,[3] the table of geologic time presented in this article conforms to the nomenclature, ages, and colour codes set forth by the ICS.[1][4]

Principles Edit

See also: Age of Earth, History of Earth, and Geological history of Earth

The geologic time scale is a way of representing deep time based on events that have occurred throughout Earth's history, a time span of about 4.54 ± 0.05 Ga (4.54 billion years).[5] It chronologically organises strata, and subsequently time, by observing fundamental changes in stratigraphy that correspond to major geological or paleontological events. For example, the Cretaceous–Paleogene extinction event, marks the lower boundary of the Paleogene System/Period and thus the boundary between the Cretaceous and Paleogene Systems/Periods. For divisions prior to the Cryogenian, arbitrary numeric boundary definitions (Global Standard Stratigraphic Ages, GSSAs) are used to divide geologic time. Proposals have been made to better reconcile these divisions with the rock record.[6][3]

Historically, regional geologic time scales were used[3] due to the litho- and biostratigraphic differences around the world in time equivalent rocks. The ICS has long worked to reconcile conflicting terminology by standardising globally significant and identifiable stratigraphic horizons that can be used to define the lower boundaries of chronostratigraphic units. Defining chronostratigraphic units in such a manner allows for the use of global, standardised nomenclature. The ICC represents this ongoing effort.

The relative relationships of rocks for determining their chronostratigraphic positions use the overriding principles of[citation needed]:

  • Superposition – Newer rock beds will lie on top of older rock beds unless the succession has been overturned.
  • Horizontality – All rock layers were originally deposited horizontally.[note 1]
  • Lateral continuity – Originally deposited layers of rock extend laterally in all directions until either thinning out or being cut off by a different rock layer.
  • Biologic succession (where applicable) – This states that each stratum in a succession contains a distinctive set of fossils. This allows for a correlation of the stratum even when the horizon between them is not continuous.
  • Cross-cutting relationships – A rock feature that cuts across another feature must be younger than the rock it cuts across.
  • Inclusion – Small fragments of one type of rock but embedded in a second type of rock must have formed first, and were included when the second rock was forming.
  • Relationships of unconformities – Geologic features representing periods of erosion or non-deposition, indicating non-continuous sediment deposition.

Terminology Edit

See also: Stratigraphy, Chronostratigraphy, Biostratigraphy, Magnetostratigraphy, Lithostratigraphy, and Geochronology

The GTS is divided into chronostratigraphic units and their corresponding geochronologic units. These are represented on the ICC published by the ICS; however, regional terms are still in use in some areas.

Chronostratigraphy is the element of stratigraphy that deals with the relation between rock bodies and the relative measurement of geological time.[7] It is the process where distinct strata between defined stratigraphic horizons are assigned to represent a relative interval of geologic time.

A chronostratigraphic unit is a body of rock, layered or unlayered, that is defined between specified stratigraphic horizons which represent specified intervals of geologic time. They include all rocks representative of a specific interval of geologic time, and only this time span.[7] Eonothem, erathem, system, series, subseries, stage, and substage are the hierarchical chronostratigraphic units.[7]Geochronology is the scientific branch of geology that aims to determine the age of rocks, fossils, and sediments either through absolute (e.g., radiometric dating) or relative means (e.g., stratigraphic position, Paleomagnetism, stable isotope ratios).[8]

A geochronologic unit is a subdivision of geologic time. It is a numeric representation of an intangible property (time).[8] Eon, era, period, epoch, subepoch, age, and subage are the hierarchical geochronologic units.[7] Geochronometry is the field of geochronology that numerically quantifies geologic time.[8]

A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundaries of stages on the geologic time scale.[9] (Recently this has been used to define the base of a system)[10]

A Global Standard Stratigraphic Age (GSSA)[11] is a numeric only, chronologic reference point used to define the base of geochronologic units prior to the Cryogenian. These points are arbitrarily defined.[7] They are used where GSSPs have not yet been established. Research is ongoing to define GSSPs for the base of all units that are currently defined by GSSAs.

The numeric (geochronometric) representation of a geochronologic unit can, and is more often subject to change when geochronology refines the geochronometry, while the equivalent chronostratigraphic unit remains the same, and their revision is less common. For example, in early 2022 the boundary between the Ediacaran and Cambrian Periods (geochronologic units) was revised from 541 Ma to 538.8 Ma but the rock definition of the boundary (GSSP) at the base of the Cambrian, and thus the boundary between the Ediacaran and Cambrian Systems (chronostratigraphic units) has not changed, merely the geochronometry has been refined.

The numeric values on the ICC are represented by the unit Ma (megaannum) meaning "million years", i.e., 201.4 ± 0.2 Ma, the lower boundary of the Jurassic Period, is defined as 201,400,000 years old with an uncertainty of 200,000 years. Other SI prefix units commonly used by geologists are Ga (gigaannum, billion years), and ka (kiloannum, thousand years), with the latter often represented in calibrated units (before present).

Divisions of geologic time Edit

An eon is the largest (formal) geochronologic time unit and is the equivalent of a chronostratigraphic eonothem.[12] As of October 2022 there are four formally defined eons/eonothems: the Hadean, Archean, Proterozoic and Phanerozoic.[2]

An era is the second largest geochronologic time unit and is the equivalent of a chronostratigraphic erathem.[7][12] As of April 2022 there are currently ten defined eras/erathems,[2] namely the Eoarchean, Paleoarchean, Mesoarchean, Neoarchean, Paleoproterozoic, Mesoproterozoic, Neoproterozoic, Paleozoic, Mesozoic and Cenozoic, with none from the Hadean eon.

A period is a major rank below an era and above an epoch. It is the geochronologic equivalent of a chronostratigraphic system.[7][12] As of April 2022 there are currently 22 defined periods/systems.[2] As an exception two subperiods/subsystems are used for the Carboniferous Period/System.[7]

An epoch is the second smallest geochronologic unit, between a period and an age. It is the equivalent of a chronostratigraphic series.[7][12] As of April 2022 there are currently 37 defined and one informal epochs/series. There are also 11 subepochs/subseries which are all within the Neogene and Quaternary.[2] The use of subseries/subepochs as formal ranks/units in international chronostratigraphy was ratified in 2022.[13]

An age is the smallest hierarchical geochronologic unit and is the equivalent of a chronostratigraphic stage.[7][12] As of April 2022 there are currently 96 formal and five informal ages/stages.[2]

A chron is a non-hierarchical formal geochronology unit of unspecified rank and is the equivalent of a chronostratigraphic chronozone.[7] These correlate with magnetostratigraphic, lithostratigraphic, or biostratigraphic units as they are based on previously defined stratigraphic units or geologic features.

The Early and Late subdivisions are used as the geochronologic equivalents of the chronostratigraphic Lower and Upper, e.g., Early Triassic Period (geochronologic unit) is used in place of Lower Triassic Series (chronostratigraphic unit).

In essence, it is true to say that rocks representing a given chronostratigraphic unit are that chronostratigraphic unit, and the time they were laid down in is the geochronologic unit, i.e., the rocks that represent the Silurian Series are the Silurian Series and they were deposited during the Silurian Period.

Formal, hierarchical units of the geologic time scale (largest to smallest)
Chronostratigraphic unit (strata) Geochronologic unit (time) Time span[note 2]
Eonothem Eon Several hundred million years to two billion years
Erathem Era Tens to hundreds of millions of years
System Period Millions of years to tens of millions of years
Series Epoch Hundreds of thousands of years to tens of millions of years
Subseries Subepoch Thousands of years to millions of years
Stage Age Thousands of years to millions of years

Naming of geologic time Edit

The names of geologic time units are defined for chronostratigraphic units with the corresponding geochronologic unit sharing the same name with a change to the latter (e.g. Phanerozoic Eonothem becomes the Phanerozoic Eon). Names of erathems in the Phanerozoic were chosen to reflect major changes in the history of life on Earth: Paleozoic (old life), Mesozoic (middle life), and Cenozoic (new life). Names of systems are diverse in origin, with some indicating chronologic position (e.g., Paleogene), while others are named for lithology (e.g., Cretaceous), geography (e.g., Permian), or are tribal (e.g., Ordovician) in origin. Most currently recognised series and subseries are named for their position within a system/series (early/middle/late); however, the ICS advocates for all new series and subseries to be named for a geographic feature in the vicinity of its stratotype or type locality. The name of stages should also be derived from a geographic feature in the locality of its stratotype or type locality.[7]

Informally, the time before the Cambrian is often referred to as the Precambrian or pre-Cambrian (Supereon).[6][note 3]

Time span and etymology of eonothem/eon names
Name Time Span Duration (million years) Etymology of name
Phanerozoic 538.8 to 0 million years ago 538.8 From the Greek words φανερός (phanerós) meaning 'visible' or 'abundant', and ζωή (zoē) meaning 'life'.
Proterozoic 2,500 to 538.8 million years ago 1961.2 From the Greek words πρότερος (próteros) meaning 'former' or 'earlier', and ζωή (zoē) meaning 'life'.
Archean 4,000 to 2,500 million years ago 1500 From the Greek word αρχή (archē), meaning 'beginning, origin'.
Hadean 4,567.3 to 4,000 million years ago 567.3 From Hades, Greek: ᾍδης, translit. Háidēs, the god of the underworld (hell, the inferno) in Greek mythology.
Time span and etymology of erathem/era names
Name Time Span Duration (million years) Etymology of name
Cenozoic 66 to 0 million years ago 66 From the Greek words καινός (kainós) meaning 'new', and ζωή (zōḗ) meaning 'life'.
Mesozoic 251.9 to 66 million years ago 185.902 From the Greek words μέσο (méso) meaning 'middle', and ζωή (zōḗ) meaning 'life'.
Paleozoic 538.8 to 251.9 million years ago 286.898 From the Greek words παλιός (palaiós) meaning 'old', and ζωή (zōḗ) meaning 'life'.
Neoproterozoic 1,000 to 538.8 million years ago 461.2 From the Greek words νέος (néos) meaning 'new' or 'young', πρότερος (próteros) meaning 'former' or 'earlier', and ζωή (zōḗ) meaning 'life'.
Mesoproterozoic 1,600 to 1,000 million years ago 600 From the Greek words μέσο (méso) meaning 'middle', πρότερος (próteros) meaning 'former' or 'earlier', and ζωή (zōḗ) meaning 'life'.
Paleoproterozoic 2,500 to 1,600 million years ago 900 From the Greek words παλιός (palaiós) meaning 'old', πρότερος (próteros) meaning 'former' or 'earlier', and ζωή (zōḗ) meaning 'life'.
Neoarchean 2,800 to 2,500 million years ago 300 From the Greek words νέος (néos) meaning 'new' or 'young', and ἀρχαῖος (arkhaîos) meaning 'ancient'.
Mesoarchean 3,200 to 2,800 million years ago 400 From the Greek words μέσο (méso) meaning 'middle', and ἀρχαῖος (arkhaîos) meaning 'ancient'.
Paleoarchean 3,600 to 3,200 million years ago 400 From the Greek words παλιός (palaiós) meaning 'old', and ἀρχαῖος (arkhaîos) meaning 'ancient'.
Eoarchean 4,000 to 3,600 million years ago 400 From the Greek words Ηώς (Ēṓs) meaning 'dawn', and ἀρχαῖος (arkhaîos) meaning 'ancient'.
Time span and etymology of system/period names
Name Time Span Duration (million years) Etymology of name
Quaternary 2.6 to 0 million years ago 2.58 First introduced by Jules Desnoyers in 1829 for sediments in France's Seine Basin that appeared to be younger than Tertiary[note 4] rocks.[14]
Neogene 23 to 2.6 million years ago 20.45 Derived from the Greek words νέος (néos) meaning 'new', and γενεά (geneá) meaning 'genesis' or 'birth'.
Paleogene 66 to 23 million years ago 42.97 Derived from the Greek words παλιός (palaiós) meaning 'old', and γενεά (geneá) meaning 'genesis' or 'birth'.
Cretaceous ~145 to 66 million years ago ~79 Derived from Terrain Crétacé used in 1822 by Jean d'Omalius d'Halloy in reference to extensive beds of chalk within the Paris Basin.[15] Ultimately derived from the Latin crēta meaning chalk.
Jurassic 201.4 to 145 million years ago ~56.4 Named after the Jura Mountains. Originally used by Alexander von Humboldt as 'Jura Kalkstein' (Jura limestone) in 1799.[16] Alexandre Brongniart was the first to publish the term Jurassic in 1829.[17][18]
Triassic 251.9 to 201.4 million years ago 50.502 From the Trias of Friedrich August von Alberti in reference to a trio of formations widespread in southern Germany.
Permian 298.9 to 251.9 million years ago 46.998 Named after the historical region of Perm, Russian Empire.[19]
Carboniferous 358.9 to 298.9 million years ago 60 Means 'coal-bearing', from the Latin carbō (coal) and ferō (to bear, carry).[20]
Devonian 419.2 to 358.9 million years ago 60.3 Named after Devon, England.[21]
Silurian 443.8 to 419.2 million years ago 24.6 Named after the Celtic tribe, the Silures.[22]
Ordovician 485.4 to 443.8 million years ago 41.6 Named after the Celtic tribe, Ordovices.[23][24]
Cambrian 538.8 to 485.4 million years ago 53.4 Named for Cambria, a latinised form of the Welsh name for Wales, Cymru.[25]
Ediacaran 635 to 538.8 million years ago ~96.2 Named for the Ediacara Hills. Ediacara is possibly a corruption of the Kuyani words 'Yata Takarra' meaning hard or stony ground.[26][27]
Cryogenian 720 to 635 million years ago ~85 From the Greek words κρύος (krýos) meaning 'cold', and, γένεσις (génesis) meaning 'birth'.[3]
Tonian 1,000 to 720 million years ago ~280 From the Greek word τόνος (tónos) meaning 'stretch'.[3]
Stenian 1,200 to 1,000 million years ago 200 From the Greek word στενός (stenós) meaning 'narrow'.[3]
Ectasian 1,400 to 1,200 million years ago 200 From the Greek word ἔκτᾰσῐς (éktasis) meaning 'extension'.[3]
Calymmian 1,600 to 1,400 million years ago 200 From the Greek word κάλυμμᾰ (kálumma) meaning 'cover'.[3]
Statherian 1,800 to 1,600 million years ago 200 From the Greek word σταθερός (statherós) meaning 'stable'.[3]
Orosirian 2,050 to 1,800 million years ago 250 From the Greek word ὀροσειρά (oroseirá) meaning 'mountain range'.[3]
Rhyacian 2,300 to 2,050 million years ago 250 From the Greek word ῥύαξ (rhýax) meaning 'stream of lava'.[3]
Siderian 2,500 to 2,300 million years ago 200 From the Greek word σίδηρος (sídēros) meaning 'iron'.[3]

History of the geologic time scale Edit

See also: History of geology and History of paleontology

Early history Edit

While a modern geological time scale was not formulated until 1911[28] by Arthur Holmes, the broader concept that rocks and time are related can be traced back to (at least) the philosophers of Ancient Greece. Xenophanes of Colophon (c. 570–487 BCE) observed rock beds with fossils of shells located above the sea-level, viewed them as once living organisms, and used this to imply an unstable relationship in which the sea had at times transgressed over the land and at other times had regressed.[29] This view was shared by a few of Xenophanes' contemporaries and those that followed, including Aristotle (384–322 BCE) who (with additional observations) reasoned that the positions of land and sea had changed over long periods of time. The concept of deep time was also recognised by Chinese naturalist Shen Kuo[30] (1031–1095) and Islamic scientist-philosophers, notably the Brothers of Purity, who wrote on the processes of stratification over the passage of time in their treatises.[29] Their work likely inspired that of the 11th-century Persian polymath Avicenna (Ibn Sînâ, 980–1037) who wrote in The Book of Healing (1027) on the concept of stratification and superposition, pre-dating Nicolas Steno by more than six centuries.[29] Avicenna also recognised fossils as "petrifications of the bodies of plants and animals",[31] with the 13th-century Dominican bishop Albertus Magnus (c. 1200–1280) extending this into a theory of a petrifying fluid.[32][verification needed] These works appeared to have little influence on scholars in Medieval Europe who looked to the Bible to explain the origins of fossils and sea-level changes, often attributing these to the 'Deluge', including Ristoro d'Arezzo in 1282.[29] It was not until the Italian Renaissance when Leonardo da Vinci (1452–1519) would reinvigorate the relationships between stratification, relative sea-level change, and time, denouncing attribution of fossils to the 'Deluge':[33][29]

Of the stupidity and ignorance of those who imagine that these creatures were carried to such places distant from the sea by the Deluge...Why do we find so many fragments and whole shells between the different layers of stone unless they had been upon the shore and had been covered over by earth newly thrown up by the sea which then became petrified? And if the above-mentioned Deluge had carried them to these places from the sea, you would find the shells at the edge of one layer of rock only, not at the edge of many where may be counted the winters of the years during which the sea multiplied the layers of sand and mud brought down by the neighboring rivers and spread them over its shores. And if you wish to say that there must have been many deluges in order to produce these layers and the shells among them it would then become necessary for you to affirm that such a deluge took place every year.

These views of da Vinci remained unpublished, and thus lacked influence at the time; however, questions of fossils and their significance were pursued and, while views against Genesis were not readily accepted and dissent from religious doctrine was in some places unwise, scholars such as Girolamo Fracastoro shared da Vinci's views, and found the attribution of fossils to the 'Deluge' absurd.[29]

Establishment of primary principles Edit

Niels Stensen, more commonly known as Nicolas Steno (1638–1686), is credited with establishing four of the guiding principles of stratigraphy.[29] In De solido intra solidum naturaliter contento dissertationis prodromus Steno states:[34][35]

  • When any given stratum was being formed, all the matter resting on it was fluid and, therefore, when the lowest stratum was being formed, none of the upper strata existed.
  • ...strata which are either perpendicular to the horizon or inclined to it were at one time parallel to the horizon.
  • When any given stratum was being formed, it was either encompassed at its edges by another solid substance or it covered the whole globe of the earth. Hence, it follows that wherever bared edges of strata are seen, either a continuation of the same strata must be looked for or another solid substance must be found that kept the material of the strata from being dispersed.
  • If a body or discontinuity cuts across a stratum, it must have formed after that stratum.

Respectively, these are the principles of superposition, original horizontality, lateral continuity, and cross-cutting relationships. From this Steno reasoned that strata were laid down in succession and inferred relative time (in Steno's belief, time from Creation). While Steno's principles were simple and attracted much attention, applying them proved challenging.[29] These basic principles, albeit with improved and more nuanced interpretations, still form the foundational principles of determining the correlation of strata relative to geologic time.

Over the course of the 18th-century geologists realised that:

  • Sequences of strata often become eroded, distorted, tilted, or even inverted after deposition
  • Strata laid down at the same time in different areas could have entirely different appearances
  • The strata of any given area represented only part of Earth's long history

Formulation of a modern geologic time scale Edit

The apparent, earliest formal division of the geologic record with respect to time was introduced by Thomas Burnet who applied a two-fold terminology to mountains by identifying "montes primarii" for rock formed at the time of the 'Deluge', and younger "monticulos secundarios" formed later from the debris of the "primarii".[36][29] This attribution to the 'Deluge', while questioned earlier by the likes of da Vinci, was the foundation of Abraham Gottlob Werner's (1749–1817) Neptunism theory in which all rocks precipitated out of a single flood.[37] A competing theory, Plutonism, was developed by Anton Moro (1687–1784) and also used primary and secondary divisions for rock units.[38][29] In this early version of the Plutonism theory, the interior of Earth was seen as hot, and this drove the creation of primary igneous and metamorphic rocks and secondary rocks formed contorted and fossiliferous sediments. These primary and secondary divisions were expanded on by Giovanni Targioni Tozzetti (1712–1783) and Giovanni Arduino (1713–1795) to include tertiary and quaternary divisions.[29] These divisions were used to describe both the time during which the rocks were laid down, and the collection of rocks themselves (i.e., it was correct to say Tertiary rocks, and Tertiary Period). Only the Quaternary division is retained in the modern geologic time scale, while the Tertiary division was in use until the early 21st century. The Neptunism and Plutonism theories would compete into the early 19th century with a key driver for resolution of this debate being the work of James Hutton (1726–1797), in particular his Theory of the Earth, first presented before the Royal Society of Edinburgh in 1785.[39][40][41] Hutton's theory would later become known as uniformitarianism, popularised by John Playfair[42] (1748–1819) and later Charles Lyell (1797–1875) in his Principles of Geology.[43][44][45] Their theories strongly contested the 6,000 year age of the Earth as suggested determined by James Ussher via Biblical chronology that was accepted at the time by western religion. Instead, using geological evidence, they contested Earth to be much older, cementing the concept of deep time.

During the early 19th century William Smith, Georges Cuvier, Jean d'Omalius d'Halloy, and Alexandre Brongniart pioneered the systematic division of rocks by stratigraphy and fossil assemblages. These geologists began to use the local names given to rock units in a wider sense, correlating strata across national and continental boundaries based on their similarity to each other. Many of the names below erathem/era rank in use on the modern ICC/GTS were determined during the early to mid-19th century.

The advent of geochronometry Edit

During the 19th century, the debate regarding Earth's age was renewed, with geologists estimating ages based on denudation rates and sedimentary thicknesses or ocean chemistry, and physicists determining ages for the cooling of the Earth or the Sun using basic thermodynamics or orbital physics.[5] These estimations varied from 15,000 million years to 0.075 million years depending on method and author, but the estimations of Lord Kelvin and Clarence King were held in high regard at the time due to their pre-eminence in physics and geology. All of these early geochronometric determinations would later prove to be incorrect.

The discovery of radioactive decay by Henri Becquerel, Marie Curie, and Pierre Curie laid the ground work for radiometric dating, but the knowledge and tools required for accurate determination of radiometric ages would not be in place until the mid-1950s.[5] Early attempts at determining ages of uranium minerals and rocks by Ernest Rutherford, Bertram Boltwood, Robert Strutt, and Arthur Holmes, would culminate in what are considered the first international geological time scales by Holmes in 1911 and 1913.[28][46][47] The discovery of isotopes in 1913[48] by Frederick Soddy, and the developments in mass spectrometry pioneered by Francis William Aston, Arthur Jeffrey Dempster, and Alfred O. C. Nier during the early to mid-20th century would finally allow for the accurate determination of radiometric ages, with Holmes publishing several revisions to his geological time-scale with his final version in 1960.[5][47][49][50]

Modern international geologic time scale Edit

The establishment of the IUGS in 1961[51] and acceptance of the Commission on Stratigraphy (applied in 1965)[52] to become a member commission of IUGS led to the founding of the ICS. One of the primary objectives of the ICS is "the establishment, publication and revision of the ICS International Chronostratigraphic Chart which is the standard, reference global Geological Time Scale to include the ratified Commission decisions".[1]

Following on from Holmes, several A Geological Time Scale books were published in 1982,[53] 1989,[54] 2004,[55] 2008,[56] 2012,[57] 2016,[58] and 2020.[59] However, since 2013, the ICS has taken responsibility for producing and distributing the ICC citing the commercial nature, independent creation, and lack of oversight by the ICS on the prior published GTS versions (GTS books prior to 2013) although these versions were published in close association with the ICS.[2] Subsequent Geologic Time Scale books (2016[58] and 2020[59]) are commercial publications with no oversight from the ICS, and do not entirely conform to the chart produced by the ICS. The ICS produced GTS charts are versioned (year/month) beginning at v2013/01. At least one new version is published each year incorporating any changes ratified by the ICS since the prior version.

The following five timelines show the geologic time scale to scale. The first shows the entire time from the formation of the Earth to the present, but this gives little space for the most recent eon. The second timeline shows an expanded view of the most recent eon. In a similar way, the most recent era is expanded in the third timeline, the most recent period is expanded in the fourth timeline, and the most recent epoch is expanded in the fifth timeline.

SiderianRhyacianOrosirianStatherianCalymmianEctasianStenianTonianCryogenianEdiacaranEoarcheanPaleoarcheanMesoarcheanNeoarcheanPaleoproterozoicMesoproterozoicNeoproterozoicPaleozoicMesozoicCenozoicHadeanArcheanProterozoicPhanerozoicPrecambrian
CambrianOrdovicianSilurianDevonianCarboniferousPermianTriassicJurassicCretaceousPaleogeneNeogeneQuaternaryPaleozoicMesozoicCenozoicPhanerozoic
PaleoceneEoceneOligoceneMiocenePliocenePleistoceneHolocenePaleogeneNeogeneQuaternaryCenozoic
GelasianCalabrian (stage)ChibanianPleistocenePleistoceneHoloceneQuaternary
GreenlandianNorthgrippianMeghalayanHolocene
Millions of Years (1st, 2nd, 3rd, and 4th)
Thousands of years (5th)

Major proposed revisions to the ICC Edit

Proposed Anthropocene Series/Epoch Edit

Main article: Anthropocene

First suggested in 2000,[60] the Anthropocene is a proposed epoch/series for the most recent time in Earth's history. While still informal, it is a widely used term to denote the present geologic time interval, in which many conditions and processes on Earth are profoundly altered by human impact.[61] As of April 2022 the Anthropocene has not been ratified by the ICS; however, in May 2019 the Anthropocene Working Group voted in favour of submitting a formal proposal to the ICS for the establishment of the Anthropocene Series/Epoch.[62] Nevertheless, the definition of the Anthropocene as a geologic time period rather than a geologic event remains controversial and difficult.[63][64][65][66]

Proposals for revisions to pre-Cryogenian timeline Edit

Shields et al. 2021 Edit

An international working group of the ICS on pre-Cryogenian chronostratigraphic subdivision have outlined a template to improve the pre-Cryogenian geologic time scale based on the rock record to bring it in line with the post-Tonian geologic time scale.[6] This work assessed the geologic history of the currently defined eons and eras of the pre-Cambrian,[note 3] and the proposals in the "Geological Time Scale" books 2004,[67] 2012,[3] and 2020.[68] Their recommend revisions[6] of the pre-Cryogenian geologic time scale were (changes from the current scale [v2022/10] are italicised):

  • Three divisions of the Archean instead of four by dropping Eoarchean, and revisions to their geochronometric definition, along with the repositioning of the Siderian into the latest Neoarchean, and a potential Kratian division in the Neoarchean.
    • Archean (4000–2450 Ma)
      • Paleoarchean (4000–3500 Ma)
      • Mesoarchean (3500–3000 Ma)
      • Neoarchean (3000–2450 Ma)
        • Kratian (no fixed time given, prior to the Siderian) – from Greek word κράτος (krátos), meaning strength.
        • Siderian (?–2450 Ma) – moved from Proterozoic to end of Archean, no start time given, base of Paleoproterozoic defines the end of the Siderian
  • Refinement of geochronometric divisions of the Proterozoic, Paleoproterozoic, repositioning of the Statherian into the Mesoproterozoic, new Skourian period/system in the Paleoproterozoic, new Kleisian or Syndian period/system in the Neoproterozoic.
    • Paleoproterozoic (2450–1800 Ma)
      • Skourian (2450–2300 Ma) – from the Greek word σκουριά (skouriá), meaning 'rust'.
      • Rhyacian (2300–2050 Ma)
      • Orosirian (2050–1800 Ma)
    • Mesoproterozoic (1800–1000 Ma)
      • Statherian (1800–1600 Ma)
      • Calymmian (1600–1400 Ma)
      • Ectasian (1400-1200 Ma)
      • Stenian (1200–1000 Ma)
    • Neoproterozoic (1000–538.8 Ma)[note 5]
      • Kleisian or Syndian (1000–800 Ma) – respectively from the Greek words κλείσιμο (kleísimo) meaning 'closure', and σύνδεση (sýndesi) meaning 'connection'.
      • Tonian (800–720 Ma)
      • Cryogenian (720–635 Ma)
      • Ediacaran (635–538.8 Ma)

Proposed pre-Cambrian timeline (Shield et al. 2021, ICS working group on pre-Cryogenian chronostratigraphy), shown to scale:[note 6]

Current ICC pre-Cambrian timeline (v2022/10), shown to scale:

Van Kranendonk et al. 2012 (GTS2012) Edit

The book, Geologic Time Scale 2012, was the last commercial publication of an international chronostratigraphic chart that was closely associated with the ICS.[2] It included a proposal to substantially revise the pre-Cryogenian time scale to reflect important events such as the formation of the solar system and the Great Oxidation Event, among others, while at the same time maintaining most of the previous chronostratigraphic nomenclature for the pertinent time span.[69] As of April 2022 these proposed changes have not been accepted by the ICS. The proposed changes (changes from the current scale [v2022/10]) are italicised:

  • Hadean Eon (4567–4030 Ma)
  • Archean Eon/Eonothem (4030–2420 Ma)
    • Paleoarchean Era/Erathem (4030–3490 Ma)
    • Mesoarchean Era/Erathem (3490–2780 Ma)
      • Vaalbaran Period/System (3490–3020 Ma) – based on the names of the Kapvaal (Southern Africa) and Pilbara (Western Australia) cratons, to reflect the growth of stable continental nuclei or proto-cratonic kernels.[57]
      • Pongolan Period/System (3020–2780 Ma) – named after the Pongola Supergroup, in reference to the well preserved evidence of terrestrial microbial communities in those rocks.[57]
    • Neoarchean Era/Erathem (2780–2420 Ma)
  • Proterozoic Eon/Eonothem (2420–538.8 Ma)[note 5]
    • Paleoproterozoic Era/Erathem (2420–1780 Ma)
      • Oxygenian Period/System (2420–2250 Ma) – named for displaying the first evidence for a global oxidising atmosphere.[57]
      • Jatulian or Eukaryian Period/System (2250–2060 Ma) – names are respectively for the Lomagundi–Jatuli δ13C isotopic excursion event spanning its duration, and for the (proposed)[72][73] first fossil appearance of eukaryotes.[57]
      • Columbian Period/System (2060–1780 Ma) – named after the supercontinent Columbia.[57]
    • Mesoproterozoic Era/Erathem (1780–850 Ma)
      • Rodinian Period/System (1780–850 Ma) – named after the supercontinent Rodinia, stable environment.[57]

Proposed pre-Cambrian timeline (GTS2012), shown to scale:

Current ICC pre-Cambrian timeline (v2022/10), shown to scale:

Table of geologic time Edit

The following table summarises the major events and characteristics of the divisions making up the geologic time scale of Earth. This table is arranged with the most recent geologic periods at the top, and the oldest at the bottom. The height of each table entry does not correspond to the duration of each subdivision of time. As such, this table is not to scale and does not accurately represent the relative time-spans of each geochronologic unit. While the Phanerozoic Eon looks longer than the rest, it merely spans ~539 million years (~12% of Earth's history), whilst the previous three eons[note 3] collectively span ~3,461 million years (~76% of Earth's history). This bias toward the most recent eon is in part due to the relative lack of information about events that occurred during the first three eons compared to the current eon (the Phanerozoic).[6][74] The use of subseries/subepochs has been ratified by the ICS.[13]

The content of the table is based on the official ICC produced and maintained by the ICS who also provide an online interactive version of this chart. The interactive version is based on a service delivering a machine-readable Resource Description Framework/Web Ontology Language representation of the time scale, which is available through the Commission for the Management and Application of Geoscience Information GeoSciML project as a service[75] and at a SPARQL end-point.[76][77]

Eonothem/
Eon 		Erathem/
Era 		System/
Period 		Series/
Epoch 		Stage/
Age 		Major events Start, million years ago
[note 7]
Phanerozoic Cenozoic
[note 4]		 Quaternary Holocene Meghalayan 4.2-kiloyear event, Austronesian expansion, increasing industrial CO2. 0.0042 *
Northgrippian 8.2-kiloyear event, Holocene climatic optimum. Sea level flooding of Doggerland and Sundaland. Sahara becomes a desert. End of Stone Age and start of recorded history. Humans finally expand into the Arctic Archipelago and Greenland. 0.0082 *
Greenlandian Climate stabilises. Current interglacial and Holocene extinction begins. Agriculture begins. Humans spread across the wet Sahara and Arabia, the Extreme North, and the Americas (mainland and the Caribbean). 0.0117 ± 0.000099 *
Pleistocene Upper/Late ('Tarantian') Eemian interglacial, last glacial period, ending with Younger Dryas. Toba eruption. Pleistocene megafauna (including the last terror birds) extinction. Humans expand into Near Oceania and the Americas. 0.129
Chibanian Mid-Pleistocene Transition occurs, high amplitude 100 ka glacial cycles. Rise of Homo sapiens. 0.774 *
Calabrian Further cooling of the climate. Giant terror birds go extinct. Spread of Homo erectus across Afro-Eurasia. 1.8 *
Gelasian Start of Quaternary glaciations and unstable climate.[78] Rise of the Pleistocene megafauna and Homo habilis. 2.58 *
Neogene Pliocene Piacenzian Greenland ice sheet develops[79] as the cold slowly intensifies towards the Pleistocene. Atmospheric O2 and CO2 content reaches present-day levels while landmasses also reach their current locations (e.g. the Isthmus of Panama joins the North and South Americas, while allowing a faunal interchange). The last non-marsupial metatherians go extinct. Australopithecus common in East Africa; Stone Age begins.[80] 3.6 *
Zanclean Zanclean flooding of the Mediterranean Basin. Cooling climate continues from the Miocene. First equines and elephantines. Ardipithecus in Africa.[80] 5.333 *
Miocene Messinian Messinian Event with hypersaline lakes in empty Mediterranean Basin. Sahara desert formation begins. Moderate icehouse climate, punctuated by ice ages and re-establishment of East Antarctic Ice Sheet. Choristoderes, the last non-crocodilian crocodylomorphs and creodonts go extinct. After separating from gorilla ancestors, chimpanzee and human ancestors gradually separate; Sahelanthropus and Orrorin in Africa. 7.246 *
Tortonian 11.63 *
Serravallian Middle Miocene climate optimum temporarily provides a warm climate.[81] Extinctions in middle Miocene disruption, decreasing shark diversity. First hippos. Ancestor of great apes. 13.82 *
Langhian 15.98 *
Burdigalian Orogeny in Northern Hemisphere. Start of Kaikoura Orogeny forming Southern Alps in New Zealand. Widespread forests slowly draw in massive amounts of CO2, gradually lowering the level of atmospheric CO2 from 650 ppmv down to around 100 ppmv during the Miocene.[82][note 8] Modern bird and mammal families become recognizable. The last of the primitive whales go extinct. Grasses become ubiquitous. Ancestor of apes, including humans.[83][84] Afro-Arabia collides with Eurasia, fully forming the Alpide Belt and closing the Tethys Ocean, while allowing a faunal interchange. At the same time, Afro-Arabia splits into Africa and West Asia. 20.44
Aquitanian 23.03 *
Paleogene Oligocene Chattian Grande Coupure extinction. Start of widespread Antarctic glaciation.[85] Rapid evolution and diversification of fauna, especially mammals (e.g. first macropods and seals). Major evolution and dispersal of modern types of flowering plants. Cimolestans, miacoids and condylarths go extinct. First neocetes (modern, fully aquatic whales) appear. 27.82 *
Rupelian 33.9 *
Eocene Priabonian Moderate, cooling climate. Archaic mammals (e.g. creodonts, miacoids, "condylarths" etc.) flourish and continue to develop during the epoch. Appearance of several "modern" mammal families. Primitive whales and sea cows diversify after returning to water. Birds continue to diversify. First kelp, diprotodonts, bears and simians. The multituberculates and leptictidans go extinct by the end of the epoch. Reglaciation of Antarctica and formation of its ice cap; End of Laramide and Sevier Orogenies of the Rocky Mountains in North America. Hellenic Orogeny begins in Greece and Aegean Sea. 37.71 *
Bartonian 41.2
Lutetian 47.8 *
Ypresian Two transient events of global warming (PETM and ETM-2) and warming climate until the Eocene Climatic Optimum. The Azolla event decreased CO2 levels from 3500 ppm to 650 ppm, setting the stage for a long period of cooling.[82][note 8] Greater India collides with Eurasia and starts Himalayan Orogeny (allowing a biotic interchange) while Eurasia completely separates from North America, creating the North Atlantic Ocean. Maritime Southeast Asia diverges from the rest of Eurasia. First passerines, ruminants, pangolins, bats and true primates. 56 *
Paleocene Thanetian Starts with Chicxulub impact and the K-Pg extinction event, wiping out all non-avian dinosaurs and pterosaurs, most marine reptiles, many other vertebrates (e.g. many Laurasian metatherians), most cephalopods (only Nautilidae and Coleoidea survived) and many other invertebrates. Climate tropical. Mammals and birds (avians) diversify rapidly into a number of lineages following the extinction event (while the marine revolution stops). Multituberculates and the first rodents widespread. First large birds (e.g. ratites and terror birds) and mammals (up to bear or small hippo size). Alpine orogeny in Europe and Asia begins. First proboscideans and plesiadapiformes (stem primates) appear. Some marsupials migrate to Australia. 59.2 *
Selandian 61.6 *
Danian 66 *
Mesozoic Cretaceous Upper/Late Maastrichtian Flowering plants proliferate (after developing many features since the Carboniferous), along with new types of insects, while other seed plants (gymnosperms and seed ferns) decline. More modern teleost fish begin to appear. Ammonoids, belemnites, rudist bivalves, sea urchins and sponges all common. Many new types of dinosaurs (e.g. tyrannosaurs, titanosaurs, hadrosaurs, and ceratopsids) evolve on land, while crocodilians appear in water and probably cause the last temnospondyls to die out; and mosasaurs and modern types of sharks appear in the sea. The revolution started by marine reptiles and sharks reaches its peak, though ichthyosaurs vanish few million years after being heavily reduced at the Bonarelli Event. Toothed and toothless avian birds coexist with pterosaurs. Modern monotremes, metatherian (including marsupials, who migrate to South America) and eutherian (including placentals, leptictidans and cimolestans) mammals appear while the last non-mammalian cynodonts die out. First terrestrial crabs. Many snails become terrestrial. Further breakup of Gondwana creates South America, Afro-Arabia, Antarctica, Oceania, Madagascar, Greater India, and the South Atlantic, Indian and Antarctic Oceans and the islands of the Indian (and some of the Atlantic) Ocean. Beginning of Laramide and Sevier Orogenies of the Rocky Mountains. Atmospheric oxygen and carbon dioxide levels similar to present day. Acritarchs disappear. Climate initially warm, but later it cools. 72.1 ± 0.2 *
Campanian 83.6 ± 0.2 *
Santonian 86.3 ± 0.5 *
Coniacian 89.8 ± 0.3 *
Turonian 93.9 *
Cenomanian 100.5 *
Lower/Early Albian ~113 *
Aptian ~121.4
Barremian ~125.77 *
Hauterivian ~132.6 *
Valanginian ~139.8
Berriasian ~145
Jurassic Upper/Late Tithonian Climate becomes humid again. Gymnosperms (especially conifers, cycads and cycadeoids) and ferns common. Dinosaurs, including sauropods, carnosaurs, stegosaurs and coelurosaurs, become the dominant land vertebrates. Mammals diversify into shuotheriids, australosphenidans, eutriconodonts, multituberculates, symmetrodonts, dryolestids and boreosphenidans but mostly remain small. First birds, lizards, snakes and turtles. First brown algae, rays, shrimps, crabs and lobsters. Parvipelvian ichthyosaurs and plesiosaurs diverse. Rhynchocephalians throughout the world. Bivalves, ammonoids and belemnites abundant. Sea urchins very common, along with crinoids, starfish, sponges, and terebratulid and rhynchonellid brachiopods. Breakup of Pangaea into Laurasia and Gondwana, with the latter also breaking into two main parts; the Pacific and Arctic Oceans form. Tethys Ocean forms. Nevadan orogeny in North America. Rangitata and Cimmerian orogenies taper off. Atmospheric CO2 levels 3–4 times the present-day levels (1200–1500 ppmv, compared to today's 400 ppmv[82][note 8]). Crocodylomorphs (last pseudosuchians) seek out an aquatic lifestyle. Mesozoic marine revolution continues from late Triassic. Tentaculitans disappear. 149.2 ± 0.9
Kimmeridgian 154.8 ± 1.0 *
Oxfordian 161.5 ± 1.0
Middle Callovian 165.3 ± 1.2
Bathonian 168.2 ± 1.3 *
Bajocian 170.9 ± 1.4 *
Aalenian 174.7 ± 1.0 *
Lower/Early Toarcian 184.2 ± 0.7 *
Pliensbachian 192.9 ± 1.0 *
Sinemurian 199.5 ± 0.3 *
Hettangian 201.4 ± 0.2 *
Triassic Upper/Late Rhaetian Archosaurs dominant on land as pseudosuchians and in the air as pterosaurs. Dinosaurs also arise from bipedal archosaurs. Ichthyosaurs and nothosaurs (a group of sauropterygians) dominate large marine fauna. Cynodonts become smaller and nocturnal, eventually becoming the first true mammals, while other remaining synapsids die out. Rhynchosaurs (archosaur relatives) also common. Seed ferns called Dicroidium remained common in Gondwana, before being replaced by advanced gymnosperms. Many large aquatic temnospondyl amphibians. Ceratitidan ammonoids extremely common. Modern corals and teleost fish appear, as do many modern insect orders and suborders. First starfish. Andean Orogeny in South America. Cimmerian Orogeny in Asia. Rangitata Orogeny begins in New Zealand. Hunter-Bowen Orogeny in Northern Australia, Queensland and New South Wales ends, (c. 260–225 Ma). Carnian pluvial event occurs around 234–232 Ma, allowing the first dinosaurs and lepidosaurs (including rhynchocephalians) to radiate. Triassic-Jurassic extinction event occurs 201 Ma, wiping out all conodonts and the last parareptiles, many marine reptiles (e.g. all sauropterygians except plesiosaurs and all ichthyosaurs except parvipelvians), all crocopodans except crocodylomorphs, pterosaurs, and dinosaurs, and many ammonoids (including the whole Ceratitida), bivalves, brachiopods, corals and sponges. First diatoms.[86] ~208.5
Norian ~227
Carnian ~237 *
Middle Ladinian ~242 *
Anisian 247.2
Lower/Early Olenekian 251.2
Induan 251.902 ± 0.024 *
Paleozoic Permian Lopingian Changhsingian Landmasses unite into supercontinent Pangaea, creating the Urals, Ouachitas and Appalachians, among other mountain ranges (the superocean Panthalassa or Proto-Pacific also forms). End of Permo-Carboniferous glaciation. Hot and dry climate. A possible drop in oxygen levels. Synapsids (pelycosaurs and therapsids) become widespread and dominant, while parareptiles and temnospondyl amphibians remain common, with the latter probably giving rise to modern amphibians in this period. In the mid-Permian, lycophytes are heavily replaced by ferns and seed plants. Beetles and flies evolve. The very large arthropods and non-tetrapod tetrapodomorphs go extinct. Marine life flourishes in warm shallow reefs; productid and spiriferid brachiopods, bivalves, forams, ammonoids (including goniatites), and orthoceridans all abundant. Crown reptiles arise from earlier diapsids, and split into the ancestors of lepidosaurs, kuehneosaurids, choristoderes, archosaurs, testudinatans, ichthyosaurs, thalattosaurs, and sauropterygians. Cynodonts evolve from larger therapsids. Olson's Extinction (273 Ma), End-Capitanian extinction (260 Ma), and Permian-Triassic extinction event (252 Ma) occur one after another: more than 80% of life on Earth becomes extinct in the lattermost, including most retarian plankton, corals (Tabulata and Rugosa die out fully), brachiopods, bryozoans, gastropods, ammonoids (the goniatites die off fully), insects, parareptiles, synapsids, amphibians, and crinoids (only articulates survived), and all eurypterids, trilobites, graptolites, hyoliths, edrioasteroid crinozoans, blastoids and acanthodians. Ouachita and Innuitian orogenies in North America. Uralian orogeny in Europe/Asia tapers off. Altaid orogeny in Asia. Hunter-Bowen Orogeny on Australian continent begins (c. 260–225 Ma), forming the New England Fold Belt. 254.14 ± 0.07 *
Wuchiapingian 259.51 ± 0.21 *
Guadalupian Capitanian 264.28 ± 0.16 *
Wordian 266.9 ± 0.4 *
Roadian 273.01 ± 0.14 *
Cisuralian Kungurian 283.5 ± 0.6
Artinskian 290.1 ± 0.26 *
Sakmarian 293.52 ± 0.17 *
Asselian 298.9 ± 0.15 *
Carboniferous
[note 9]		 Pennsylvanian
[note 10]		 Gzhelian Winged insects radiate suddenly; some (esp. Protodonata and Palaeodictyoptera) of them as well some millipedes and scorpions become very large. First coal forests (scale trees, ferns, club trees, giant horsetails, Cordaites, etc.). Higher atmospheric oxygen levels. Ice Age continues to the Early Permian. Goniatites, brachiopods, bryozoa, bivalves, and corals plentiful in the seas and oceans. First woodlice. Testate forams proliferate. Euramerica collides with Gondwana and Siberia-Kazakhstania, the latter of which forms Laurasia and the Uralian orogeny. Variscan orogeny continues (these collisions created orogenies, and ultimately Pangaea). Amphibians (e.g. temnospondyls) spread in Euramerica, with some becoming the first amniotes. Carboniferous Rainforest Collapse occurs, initiating a dry climate which favors amniotes over amphibians. Amniotes diversify rapidly into synapsids, parareptiles, cotylosaurs, protorothyridids and diapsids. Rhizodonts remained common before they died out by the end of the period. First sharks. 303.7
Kasimovian 307 ± 0.1
Moscovian 315.2 ± 0.2
Bashkirian 323.2 *
Mississippian
[note 10]		 Serpukhovian Large lycopodian primitive trees flourish and amphibious eurypterids live amid coal-forming coastal swamps, radiating significantly one last time. First gymnosperms. First holometabolous, paraneopteran, polyneopteran, odonatopteran and ephemeropteran insects and first barnacles. First five-digited tetrapods (amphibians) and land snails. In the oceans, bony and cartilaginous fishes are dominant and diverse; echinoderms (especially crinoids and blastoids) abundant. Corals, bryozoans, orthoceridans, goniatites and brachiopods (Productida, Spiriferida, etc.) recover and become very common again, but trilobites and nautiloids decline. Glaciation in East Gondwana continues from Late Devonian. Tuhua Orogeny in New Zealand tapers off. Some lobe finned fish called rhizodonts become abundant and dominant in freshwaters. Siberia collides with a different small continent, Kazakhstania. 330.9 ± 0.2
Viséan 346.7 ± 0.4 *
Tournaisian 358.9 ± 0.4 *
Devonian Upper/Late Famennian First lycopods, ferns, seed plants (seed ferns, from earlier progymnosperms), first trees (the progymnosperm Archaeopteris), and first winged insects (palaeoptera and neoptera). Strophomenid and atrypid brachiopods, rugose and tabulate corals, and crinoids are all abundant in the oceans. First fully coiled cephalopods (Ammonoidea and Nautilida, independently) with the former group very abundant (especially goniatites). Trilobites and ostracoderms decline, while jawed fishes (placoderms, lobe-finned and ray-finned bony fish, and acanthodians and early cartilaginous fish) proliferate. Some lobe finned fish transform into digited fishapods, slowly becoming amphibious. The last non-trilobite artiopods die off. First decapods (like prawns) and isopods. Pressure from jawed fishes cause eurypterids to decline and some cephalopods to lose their shells while anomalocarids vanish. "Old Red Continent" of Euramerica persists after forming in the Caledonian orogeny. Beginning of Acadian Orogeny for Anti-Atlas Mountains of North Africa, and Appalachian Mountains of North America, also the Antler, Variscan, and Tuhua orogenies in New Zealand. A series of extinction events, including the massive Kellwasser and Hangenberg ones, wipe out many acritarchs, corals, sponges, molluscs, trilobites, eurypterids, graptolites, brachiopods, crinozoans (e.g. all cystoids), and fish, including all placoderms and ostracoderms. 372.2 ± 1.6 *
Frasnian 382.7 ± 1.6 *
Middle Givetian 387.7 ± 0.8 *
Eifelian 393.3 ± 1.2 *
Lower/Early Emsian 407.6 ± 2.6 *
Pragian 410.8 ± 2.8 *
Lochkovian 419.2 ± 3.2 *
Silurian Pridoli Ozone layer thickens. First vascular plants and fully terrestrialised arthropods: myriapods, hexapods (including insects), and arachnids. Eurypterids diversify rapidly, becoming widespread and dominant. Cephalopods continue to flourish. True jawed fishes, along with ostracoderms, also roam the seas. Tabulate and rugose corals, brachiopods (Pentamerida, Rhynchonellida, etc.), cystoids and crinoids all abundant. Trilobites and molluscs diverse; graptolites not as varied. Three minor extinction events. Some echinoderms go extinct. Beginning of Caledonian Orogeny (collision between Laurentia, Baltica and one of the formerly small Gondwanan terranes) for hills in England, Ireland, Wales, Scotland, and the Scandinavian Mountains. Also continued into Devonian period as the Acadian Orogeny, above (thus Euramerica forms). Taconic Orogeny tapers off. Icehouse period ends late in this period after starting in Late Ordovician. Lachlan Orogeny on Australian continent tapers off. 423 ± 2.3 *
Ludlow Ludfordian 425.6 ± 0.9 *
Gorstian 427.4 ± 0.5 *
Wenlock Homerian 430.5 ± 0.7 *
Sheinwoodian 433.4 ± 0.8 *
Llandovery Telychian 438.5 ± 1.1 *
Aeronian 440.8 ± 1.2 *
Rhuddanian 443.8 ± 1.5 *
Ordovician Upper/Late Hirnantian The Great Ordovician Biodiversification Event occurs as plankton increase in number: invertebrates diversify into many new types (especially brachiopods and molluscs; e.g. long straight-shelled cephalopods like the long lasting and diverse Orthocerida). Early corals, articulate brachiopods (Orthida, Strophomenida, etc.), bivalves, cephalopods (nautiloids), trilobites, ostracods, bryozoans, many types of echinoderms (blastoids, cystoids, crinoids, sea urchins, sea cucumbers, and star-like forms, etc.), branched graptolites, and other taxa all common. Acritarchs still persist and common. Cephalopods become dominant and common, with some trending toward a coiled shell. Anomalocarids decline. Mysterious tentaculitans appear. First eurypterids and ostracoderm fish appear, the latter probably giving rise to the jawed fish at the end of the period. First uncontroversial terrestrial fungi and fully terrestrialised plants. Ice age at the end of this period, as well as a series of mass extinction events, killing off some cephalopods and many brachiopods, bryozoans, echinoderms, graptolites, trilobites, bivalves, corals and conodonts. 445.2 ± 1.4 *
Katian 453 ± 0.7 *
Sandbian 458.4 ± 0.9 *
Middle Darriwilian 467.3 ± 1.1 *
Dapingian 470 ± 1.4 *
Lower/Early Floian
(formerly Arenig) 		477.7 ± 1.4 *
Tremadocian 485.4 ± 1.9 *
Cambrian Furongian Stage 10 Major diversification of (fossils mainly show bilaterian) life in the Cambrian Explosion as oxygen levels increase. Numerous fossils; most modern animal phyla (including arthropods, molluscs, annelids, echinoderms, hemichordates and chordates) appear. Reef-building archaeocyathan sponges initially abundant, then vanish. Stromatolites replace them, but quickly fall prey to the Agronomic revolution, when some animals started burrowing through the microbial mats (affecting some other animals as well). First artiopods (including trilobites), priapulid worms, inarticulate brachiopods (unhinged lampshells), hyoliths, bryozoans, graptolites, pentaradial echinoderms (e.g. blastozoans, crinozoans and eleutherozoans), and numerous other animals. Anomalocarids are dominant and giant predators, while many Ediacaran fauna die out. Crustaceans and molluscs diversify rapidly. Prokaryotes, protists (e.g., forams), algae and fungi continue to present day. First vertebrates from earlier chordates. Petermann Orogeny on the Australian continent tapers off (550–535 Ma). Ross Orogeny in Antarctica. Delamerian Orogeny (c. 514–490 Ma) on Australian continent. Some small terranes split off from Gondwana. Atmospheric CO2 content roughly 15 times present-day (Holocene) levels (6000 ppm compared to today's 400 ppm)[82][note 8] Arthropods and streptophyta start colonising land. 3 extinction events occur 517, 502 & 488 Ma, the first and last of which wipe out many of the anomalocarids, artiopods, hyoliths, brachiopods, molluscs, and conodonts (early jawless vertebrates). ~489.5
Jiangshanian ~494 *
Paibian ~497 *
Miaolingian Guzhangian ~500.5 *
Drumian ~504.5 *
Wuliuan ~509
Series 2 Stage 4 ~514
Stage 3 ~521
Terreneuvian Stage 2 ~529
Fortunian 538.8 ± 0.2 *
Proterozoic Neoproterozoic Ediacaran Good fossils of primitive animals. Ediacaran biota flourish worldwide in seas, possibly appearing after an explosion, possibly caused by a large-scale oxidation event.[87] First vendozoans (unknown affinity among animals), cnidarians and bilaterians. Enigmatic vendozoans include many soft-jellied creatures shaped like bags, disks, or quilts (like Dickinsonia). Simple trace fossils of possible worm-like Trichophycus, etc.Taconic Orogeny in North America. Aravalli Range orogeny in Indian subcontinent. Beginning of Pan-African Orogeny, leading to the formation of the short-lived Ediacaran supercontinent Pannotia, which by the end of the period breaks up into Laurentia, Baltica, Siberia and Gondwana. Petermann Orogeny forms on Australian continent. Beardmore Orogeny in Antarctica, 633–620 Ma. Ozone layer forms. An increase in oceanic mineral levels. ~635 *
Cryogenian Possible "Snowball Earth" period. Fossils still rare. Late Ruker / Nimrod Orogeny in Antarctica tapers off. First uncontroversial animal fossils. First hypothetical terrestrial fungi[88] and streptophyta.[89] ~720
Tonian Final assembly of Rodinia supercontinent occurs in early Tonian, with breakup beginning c. 800 Ma. Sveconorwegian orogeny ends. Grenville Orogeny tapers off in North America. Lake Ruker / Nimrod Orogeny in Antarctica, 1,000 ± 150 Ma. Edmundian Orogeny (c. 920–850 Ma), Gascoyne Complex, Western Australia. Deposition of Adelaide Superbasin and Centralian Superbasin begins on Australian continent. First hypothetical animals (from holozoans) and terrestrial algal mats. Many endosymbiotic events concerning red and green algae occur, transferring plastids to ochrophyta (e.g. diatoms, brown algae), dinoflagellates, cryptophyta, haptophyta, and euglenids (the events may have begun in the Mesoproterozoic)[90] while the first retarians (e.g. forams) also appear: eukaryotes diversify rapidly, including algal, eukaryovoric and biomineralised forms. Trace fossils of simple multi-celled eukaryotes. 1000 [note 11]
Mesoproterozoic Stenian Narrow highly metamorphic belts due to orogeny as Rodinia forms, surrounded by the Pan-African Ocean. Sveconorwegian orogeny starts. Late Ruker / Nimrod Orogeny in Antarctica possibly begins. Musgrave Orogeny (c. 1,080–), Musgrave Block, Central Australia. Stromatolites decline as algae proliferate. 1200 [note 11]
Ectasian Platform covers continue to expand. Algal colonies in the seas. Grenville Orogeny in North America. Columbia breaks up. 1400 [note 11]
Calymmian Platform covers expand. Barramundi Orogeny, McArthur Basin, Northern Australia, and Isan Orogeny, c. 1,600 Ma, Mount Isa Block, Queensland. First archaeplastidans (the first eukaryotes with plastids from cyanobacteria; e.g. red and green algae) and opisthokonts (giving rise to the first fungi and holozoans). Acritarchs (remains of marine algae possibly) start appearing in the fossil record. 1600 [note 11]
Paleoproterozoic Statherian First uncontroversial eukaryotes: protists with nuclei and endomembrane system. Columbia forms as the second undisputed earliest supercontinent. Kimban Orogeny in Australian continent ends. Yapungku Orogeny on Yilgarn craton, in Western Australia. Mangaroon Orogeny, 1,680–1,620 Ma, on the Gascoyne Complex in Western Australia. Kararan Orogeny (1,650 Ma), Gawler Craton, South Australia. Oxygen levels drop again. 1800 [note 11]
Orosirian The atmosphere becomes much more oxygenic while more cyanobacterial stromatolites appear. Vredefort and Sudbury Basin asteroid impacts. Much orogeny. Penokean and Trans-Hudsonian Orogenies in North America. Early Ruker Orogeny in Antarctica, 2,000–1,700 Ma. Glenburgh Orogeny, Glenburgh Terrane, Australian continent c. 2,005–1,920 Ma. Kimban Orogeny, Gawler craton in Australian continent begins. 2050 [note 11]
Rhyacian Bushveld Igneous Complex forms. Huronian glaciation. First hypothetical eukaryotes. Multicellular Francevillian biota. Kenorland disassembles. 2300 [note 11]
Siderian Great Oxidation Event (due to cyanobacteria) increases oxygen. Sleaford Orogeny on Australian continent, Gawler Craton 2,440–2,420 Ma. 2500 [note 11]
Archean Neoarchean Stabilization of most modern cratons; possible mantle overturn event. Insell Orogeny, 2,650 ± 150 Ma. Abitibi greenstone belt in present-day Ontario and Quebec begins to form, stabilises by 2,600 Ma. First uncontroversial supercontinent, Kenorland, and first terrestrial prokaryotes. 2800 [note 11]
Mesoarchean First stromatolites (probably colonial phototrophic bacteria, like cyanobacteria). Oldest macrofossils. Humboldt Orogeny in Antarctica. Blake River Megacaldera Complex begins to form in present-day Ontario and Quebec, ends by roughly 2,696 Ma. 3200 [note 11]
Paleoarchean Prokaryotic archaea (e.g. methanogens) and bacteria (e.g. cyanobacteria) diversify rapidly, along with early viruses. First known phototrophic bacteria. Oldest definitive microfossils. First microbial mats. Oldest cratons on Earth (such as the Canadian Shield and the Pilbara Craton) may have formed during this period.[note 12] Rayner Orogeny in Antarctica. 3600 [note 11]
Eoarchean First uncontroversial living organisms: at first protocells with RNA-based genes around 4000 Ma, after which true cells (prokaryotes) evolve along with proteins and DNA-based genes around 3800 Ma. The end of the Late Heavy Bombardment. Napier Orogeny in Antarctica, 4,000 ± 200 Ma. 4000 [note 11]
Hadean Formation of protolith of the oldest known rock (Acasta Gneiss) c. 4,031 to 3,580 Ma.[91][92] Possible first appearance of plate tectonics. First hypothetical life forms. End of the Early Bombardment Phase. Oldest known mineral (Zircon, 4,404 ± 8 Ma).[93] Asteroids and comets bring water to Earth, forming the first oceans. Formation of Moon (4,510 Ma), probably from a giant impact. Formation of Earth (4,543 to 4,540 Ma) 4567.3 ± 0.16 [note 11]

Non-Earth based geologic time scales Edit

Main articles: Lunar geologic timescale, Martian geologic timescale, and Geology of Venus

Some other planets and satellites in the Solar System have sufficiently rigid structures to have preserved records of their own histories, for example, Venus, Mars and the Earth's Moon. Dominantly fluid planets, such as the gas giants, do not comparably preserve their history. Apart from the Late Heavy Bombardment, events on other planets probably had little direct influence on the Earth, and events on Earth had correspondingly little effect on those planets. Construction of a time scale that links the planets is, therefore, of only limited relevance to the Earth's time scale, except in a Solar System context. The existence, timing, and terrestrial effects of the Late Heavy Bombardment are still a matter of debate.[note 13]

Lunar (selenological) time scale Edit

The geologic history of Earth's Moon has been divided into a time scale based on geomorphological markers, namely impact cratering, volcanism, and erosion. This process of dividing the Moon's history in this manner means that the time scale boundaries do not imply fundamental changes in geological processes, unlike Earth's geologic time scale. Five geologic systems/periods (Pre-Nectarian, Nectarian, Imbrian, Eratosthenian, Copernican), with the Imbrian divided into two series/epochs (Early and Late) were defined in the latest Lunar geologic time scale.[94] The Moon is unique in the Solar System in that it is the only other body from which we have rock samples with a known geological context.

Early ImbrianLate ImbrianPre-NectarianNectarianEratosthenianCopernican period
Millions of years before present


Martian geologic time scale Edit

The geological history of Mars has been divided into two alternate time scales. The first time scale for Mars was developed by studying the impact crater densities on the Martian surface. Through this method four periods have been defined, the Pre-Noachian (~4,500–4,100 Ma), Noachian (~4,100–3,700 Ma), Hesperian (~3,700–3,000 Ma), and Amazonian (~3,000 Ma to present).[95][96]

NoachianNoachianHesperianAmazonian (Mars)
Martian time periods (millions of years ago)

A second time scale based on mineral alteration observed by the OMEGA spectrometer on-board the Mars Express. Using this method, three periods were defined, the Phyllocian (~4,500–4,000 Ma), Theiikian (~4,000–3,500 Ma), and Siderikian (~3,500 Ma to present).[97]

See also Edit

Notes Edit

  1. ^ It is now known that not all sedimentary layers are deposited purely horizontally, but this principle is still a useful concept.
  2. ^ Time spans of geologic time units vary broadly, and there is no numeric limitation on the time span they can represent. They are limited by the time span of the higher rank unit they belong to, and to the chronostratigraphic boundaries they are defined by.
  3. ^ a b c Precambrian or pre-Cambrian is an informal geological term for time before the Cambrian period
  4. ^ a b The Tertiary is a now obsolete geologic system/period spanning from 66 Ma to 2.6 Ma. It has no exact equivalent in the modern ICC, but is approximately equivalent to the merged Palaeogene and Neogene systems/periods.
  5. ^ a b Geochronometric date for the Ediacaran has been adjusted to reflect ICC v2022/10 as the formal definition for the base of the Cambrian has not changed.
  6. ^ Kratian time span is not given in the article. It lies within the Neoarchean, and prior to the Siderian. The position shown here is an arbitrary division.
  7. ^ The dates and uncertainties quoted are according to the International Commission on Stratigraphy International Chronostratigraphic chart (v2023/06). A * indicates boundaries where a Global Boundary Stratotype Section and Point has been internationally agreed.
  8. ^ a b c d For more information on this, see Atmosphere of Earth#Evolution of Earth's atmosphere, Carbon dioxide in the Earth's atmosphere, and climate change. Specific graphs of reconstructed CO2 levels over the past ~550, 65, and 5 million years can be seen at File:Phanerozoic Carbon Dioxide.png, File:65 Myr Climate Change.png, File:Five Myr Climate Change.png, respectively.
  9. ^ The Mississippian and Pennsylvanian are official sub-systems/sub-periods.
  10. ^ a b This is divided into Lower/Early, Middle, and Upper/Late series/epochs
  11. ^ a b c d e f g h i j k l m Defined by absolute age (Global Standard Stratigraphic Age).
  12. ^ The age of the oldest measurable craton, or continental crust, is dated to 3,600–3,800 Ma.
  13. ^ Not enough is known about extra-solar planets for worthwhile speculation.

References Edit

  1. ^ a b c "Statues & Guidelines". International Commission on Stratigraphy. Retrieved 5 April 2022.
  2. ^ a b c d e f g h i Cohen, K.M.; Finney, S.C.; Gibbard, P.L.; Fan, J.-X. (1 September 2013). "The ICS International Chronostratigraphic Chart". Episodes (updated ed.). 36 (3): 199–204. doi:10.18814/epiiugs/2013/v36i3/002. ISSN 0705-3797. S2CID 51819600.
  3. ^ a b c d e f g h i j k l m Van Kranendonk, Martin J.; Altermann, Wladyslaw; Beard, Brian L.; Hoffman, Paul F.; Johnson, Clark M.; Kasting, James F.; Melezhik, Victor A.; Nutman, Allen P. (2012), "A Chronostratigraphic Division of the Precambrian", The Geologic Time Scale, Elsevier, pp. 299–392, doi:10.1016/b978-0-444-59425-9.00016-0, ISBN 978-0-444-59425-9, retrieved 5 April 2022
  4. ^ "International Commission on Stratigraphy". International Geological Time Scale. Retrieved 5 June 2022.
  5. ^ a b c d Dalrymple, G. Brent (2001). "The age of the Earth in the twentieth century: a problem (mostly) solved". Special Publications, Geological Society of London. 190 (1): 205–221. Bibcode:2001GSLSP.190..205D. doi:10.1144/GSL.SP.2001.190.01.14. S2CID 130092094.
  6. ^ a b c d e Shields, Graham A.; Strachan, Robin A.; Porter, Susannah M.; Halverson, Galen P.; Macdonald, Francis A.; Plumb, Kenneth A.; de Alvarenga, Carlos J.; Banerjee, Dhiraj M.; Bekker, Andrey; Bleeker, Wouter; Brasier, Alexander (2022). "A template for an improved rock-based subdivision of the pre-Cryogenian timescale". Journal of the Geological Society. 179 (1): jgs2020–222. Bibcode:2022JGSoc.179..222S. doi:10.1144/jgs2020-222. ISSN 0016-7649. S2CID 236285974.
  7. ^ a b c d e f g h i j k l "Chapter 9. Chronostratigraphic Units". stratigraphy.org. International Commission on Stratigraphy. Retrieved 2 April 2022.
  8. ^ a b c "Chapter 3. Definitions and Procedures". stratigraphy.org. International Commission on Stratigraphy. Retrieved 2 April 2022.
  9. ^ "Global Boundary Stratotype Section and Points". stratigraphy.org. International Commission on Stratigraphy. Retrieved 2 April 2022.
  10. ^ Knoll, Andrew; Walter, Malcolm; Narbonne, Guy; Christie-Blick, Nicholas (2006). "The Ediacaran Period: a new addition to the geologic time scale". Lethaia. 39 (1): 13–30. doi:10.1080/00241160500409223.
  11. ^ Remane, Jürgen; Bassett, Michael G; Cowie, John W; Gohrbandt, Klaus H; Lane, H Richard; Michelsen, Olaf; Naiwen, Wang; the cooperation of members of ICS (1 September 1996). "Revised guidelines for the establishment of global chronostratigraphic standards by the International Commission on Stratigraphy (ICS)". Episodes. 19 (3): 77–81. doi:10.18814/epiiugs/1996/v19i3/007. ISSN 0705-3797.
  12. ^ a b c d e Michael Allaby (2020). A dictionary of geology and earth sciences (Fifth ed.). Oxford. ISBN 978-0-19-187490-1. OCLC 1137380460.{{cite book}}: CS1 maint: location missing publisher (link)
  13. ^ a b Aubry, Marie-Pierre; Piller, Werner E.; Gibbard, Philip L.; Harper, David A. T.; Finney, Stanley C. (1 March 2022). "Ratification of subseries/subepochs as formal rank/units in international chronostratigraphy". Episodes. 45 (1): 97–99. doi:10.18814/epiiugs/2021/021016. ISSN 0705-3797. S2CID 240772165.
  14. ^ Desnoyers, J. (1829). "Observations sur un ensemble de dépôts marins plus récents que les terrains tertiaires du bassin de la Seine, et constituant une formation géologique distincte; précédées d'un aperçu de la nonsimultanéité des bassins tertiares" [Observations on a set of marine deposits [that are] more recent than the tertiary terrains of the Seine basin and [that] constitute a distinct geological formation; preceded by an outline of the non-simultaneity of tertiary basins]. Annales des Sciences Naturelles (in French). 16: 171–214, 402–491. From p. 193: "Ce que je désirerais ... dont il faut également les distinguer." (What I would desire to prove above all is that the series of tertiary deposits continued – and even began in the more recent basins – for a long time, perhaps after that of the Seine had been completely filled, and that these later formations – Quaternary (1), so to say – should not retain the name of alluvial deposits any more than the true and ancient tertiary deposits, from which they must also be distinguished.) However, on the very same page, Desnoyers abandoned the use of the term "Quaternary" because the distinction between Quaternary and Tertiary deposits wasn't clear. From p. 193: "La crainte de voir mal comprise ... que ceux du bassin de la Seine." (The fear of seeing my opinion in this regard be misunderstood or exaggerated, has made me abandon the word "quaternary", which at first I had wanted to apply to all deposits more recent than those of the Seine basin.)
  15. ^ d'Halloy, d'O., J.-J. (1822). "Observations sur un essai de carte géologique de la France, des Pays-Bas, et des contrées voisines" [Observations on a trial geological map of France, the Low Countries, and neighboring countries]. Annales des Mines. 7: 353–376.{{cite journal}}: CS1 maint: multiple names: authors list (link) From page 373: "La troisième, qui correspond à ce qu'on a déja appelé formation de la craie, sera désigné par le nom de terrain crétacé." (The third, which corresponds to what was already called the "chalk formation", will be designated by the name "chalky terrain".)
  16. ^ Humboldt, Alexander von (1799). Ueber die unterirdischen Gasarten und die Mittel ihren Nachtheil zu vermindern: ein Beytrag zur Physik der praktischen Bergbaukunde (in German). Vieweg.
  17. ^ Brongniart, Alexandre (1770-1847) Auteur du texte (1829). Tableau des terrains qui composent l'écorce du globe ou Essai sur la structure de la partie connue de la terre . Par Alexandre Brongniart,... (in French).
  18. ^ Ogg, J.G.; Hinnov, L.A.; Huang, C. (2012), "Jurassic", The Geologic Time Scale, Elsevier, pp. 731–791, doi:10.1016/b978-0-444-59425-9.00026-3, ISBN 978-0-444-59425-9, retrieved 1 May 2022
  19. ^ Murchison; Murchison, Sir Roderick Impey; Verneuil; Keyserling, Graf Alexander (1842). On the Geological Structure of the Central and Southern Regions of Russia in Europe, and of the Ural Mountains. Print. by R. and J.E. Taylor.
  20. ^ Phillips, John (1835). Illustrations of the Geology of Yorkshire: Or, A Description of the Strata and Organic Remains: Accompanied by a Geological Map, Sections and Plates of the Fossil Plants and Animals ... J. Murray.
  21. ^ Sedgwick, A.; Murchison, R. I. (1 January 1840). "XLIII.--On the Physical Structure of Devonshire, and on the Subdivisions and Geological Relations of its older stratified Deposits, &c". Transactions of the Geological Society of London. s2-5 (3): 633–703. doi:10.1144/transgslb.5.3.633. ISSN 2042-5295. S2CID 128475487.
  22. ^ Murchison, Roderick Impey (1835). "VII. On the silurian system of rocks". The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science. 7 (37): 46–52. doi:10.1080/14786443508648654. ISSN 1941-5966.
  23. ^ Lapworth, Charles (1879). "I.—On the Tripartite Classification of the Lower Palæozoic Rocks". Geological Magazine. 6 (1): 1–15. Bibcode:1879GeoM....6....1L. doi:10.1017/S0016756800156560. ISSN 0016-7568. S2CID 129165105.
  24. ^ Bassett, Michael G. (1 June 1979). "100 Years of Ordovician Geology". Episodes. 2 (2): 18–21. doi:10.18814/epiiugs/1979/v2i2/003. ISSN 0705-3797.
  25. ^ Chisholm, Hugh, ed. (1911). "Cambria" . Encyclopædia Britannica (11th ed.). Cambridge University Press.
  26. ^ Butcher, Andy (26 May 2004). . LISTSERV 16.0 - AUSTRALIAN-LINGUISTICS-L Archives. Archived from the original on 23 October 2007. Retrieved 19 July 2011.
  27. ^ "Place Details: Ediacara Fossil Site – Nilpena, Parachilna, SA, Australia". Department of Sustainability, Environment, Water, Population and Communities. Australian Heritage Database. Commonwealth of Australia. from the original on 3 June 2011. Retrieved 19 July 2011.
  28. ^ a b Holmes, Arthur (9 June 1911). "The association of lead with uranium in rock-minerals, and its application to the measurement of geological time". Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character. 85 (578): 248–256. Bibcode:1911RSPSA..85..248H. doi:10.1098/rspa.1911.0036. ISSN 0950-1207.
  29. ^ a b c d e f g h i j k Fischer, Alfred G.; Garrison, Robert E. (2009). "The role of the Mediterranean region in the development of sedimentary geology: a historical overview". Sedimentology. 56 (1): 3–41. Bibcode:2009Sedim..56....3F. doi:10.1111/j.1365-3091.2008.01009.x. S2CID 128604255.
  30. ^ Sivin, Nathan (1995). Science in ancient China : researches and reflections. Variorum. ISBN 0-86078-492-4. OCLC 956775994.
  31. ^ Adams, Frank D. (1938). The Birth and Development of the Geological Sciences. Williams & Wilkins. ISBN 0-486-26372-X. OCLC 165626104.
  32. ^ Rudwick, M. J. S. (1985). The meaning of fossils : episodes in the history of palaeontology. Chicago: University of Chicago Press. ISBN 0-226-73103-0. OCLC 11574066.
  33. ^ McCurdy, Edward (1938). The notebooks of Leonardo da Vinci. New York: Reynal & Hitchcock. OCLC 2233803.
  34. ^ Steno, Nicolaus (1669). Nicolai Stenonis de solido intra solidvm natvraliter contento dissertationis prodromvs ad serenissimvm Ferdinandvm II ... (in Latin). W. Junk.
  35. ^ Kardel, Troels; Maquet, Paul (2018), "2.27 the Prodromus to a Dissertation on a Solid Naturally Contained within a Solid", Nicolaus Steno, Berlin, Heidelberg: Springer Berlin Heidelberg, pp. 763–825, doi:10.1007/978-3-662-55047-2_38, ISBN 978-3-662-55046-5, retrieved 20 April 2022
  36. ^ Burnet, Thomas (1681). Telluris Theoria Sacra: orbis nostri originen et mutationes generales, quasi am subiit aut olim subiturus est, complectens. Libri duo priores de Diluvio & Paradiso (in Latin). London: G. Kettiby.
  37. ^ Werner, Abraham Gottlob (1787). Kurze Klassifikation und Beschreibung der verschiedenen Gebirgsarten (in German). Dresden: Walther.
  38. ^ Moro, Anton Lazzaro (1740). De'crostacei e degli altri marini corpi che si truovano su'monti (in Italian). Appresso Stefano Monti.
  39. ^ Hutton, James (1788). "X. Theory of the Earth; or an Investigation of the Laws observable in the Composition, Dissolution, and Restoration of Land upon the Globe ". Transactions of the Royal Society of Edinburgh. 1 (2): 209–304. doi:10.1017/S0080456800029227. ISSN 0080-4568. S2CID 251578886.
  40. ^ Hutton, James (1795). Theory of the Earth. Vol. 1. Edinburgh.
  41. ^ Hutton, James (1795). Theory of the Earth. Vol. 2. Edinburgh.
  42. ^ Playfair, John (1802). Illustrations of the Huttonian theory of the earth. Digitised by London Natural History Museum Library. Edinburgh: Neill & Co.
  43. ^ Lyell, Sir Charles (1832). Principles of Geology: Being an Attempt to Explain the Former Changes of the Earth's Surface, by Reference to Causes Now in Operation. Vol. 1. London: John Murray.
  44. ^ Lyell, Sir Charles (1832). Principles of Geology: Being an Attempt to Explain the Former Changes of the Earth's Surface, by Reference to Causes Now in Operation. Vol. 2. London: John Murray.
  45. ^ Lyell, Sir Charles (1834). Principles of Geology: Being an Inquiry how for the Former Changes of the Earth's Surface are Referrable to Causes Now in Operation. Vol. 3. London: John Murray.
  46. ^ Holmes, Arthur (1913). The age of the earth. Gerstein - University of Toronto. London, Harper.
  47. ^ a b Lewis, Cherry L. E. (2001). "Arthur Holmes' vision of a geological timescale". Geological Society, London, Special Publications. 190 (1): 121–138. Bibcode:2001GSLSP.190..121L. doi:10.1144/GSL.SP.2001.190.01.10. ISSN 0305-8719. S2CID 128686640.
  48. ^ Soddy, Frederick (4 December 1913). "Intra-atomic Charge". Nature. 92 (2301): 399–400. Bibcode:1913Natur..92..399S. doi:10.1038/092399c0. ISSN 0028-0836. S2CID 3965303.
  49. ^ Holmes, A. (1 January 1959). "A revised geological time-scale". Transactions of the Edinburgh Geological Society. 17 (3): 183–216. doi:10.1144/transed.17.3.183. ISSN 0371-6260. S2CID 129166282.
  50. ^ "A Revised Geological Time-Scale". Nature. 187 (4731): 27–28. 1960. Bibcode:1960Natur.187T..27.. doi:10.1038/187027d0. ISSN 0028-0836. S2CID 4179334.
  51. ^ Harrison, James M. (1 March 1978). "The Roots of IUGS". Episodes. 1 (1): 20–23. doi:10.18814/epiiugs/1978/v1i1/005. ISSN 0705-3797.
  52. ^ International Union of Geological Sciences. Commission on Stratigraphy (1986). Guidelines and statutes of the International Commission on Stratigraphy (ICS). J. W. Cowie. Frankfurt a.M.: Herausgegeben von der Senckenbergischen Naturforschenden Gesellschaft. ISBN 3-924500-19-3. OCLC 14352783.
  53. ^ W. B. Harland (1982). A geologic time scale. Cambridge [England]: Cambridge University Press. ISBN 0-521-24728-4. OCLC 8387993.
  54. ^ W. B. Harland (1990). A geologic time scale 1989. Cambridge: Cambridge University Press. ISBN 0-521-38361-7. OCLC 20930970.
  55. ^ F. M. Gradstein; James G. Ogg; A. Gilbert Smith (2004). A geologic time scale 2004. Cambridge, UK: Cambridge University Press. ISBN 0-511-08201-0. OCLC 60770922.
  56. ^ Gradstein, Felix M.; Ogg, James G.; van Kranendonk, Martin (23 July 2008). "On the Geologic Time Scale 2008". Newsletters on Stratigraphy. 43 (1): 5–13. doi:10.1127/0078-0421/2008/0043-0005. ISSN 0078-0421.
  57. ^ a b c d e f g h i j k l m F. M. Gradstein (2012). The geologic time scale 2012. Volume 2 (1st ed.). Amsterdam: Elsevier. ISBN 978-0-444-59448-8. OCLC 808340848.
  58. ^ a b Ogg, James G. (2016). A concise geologic time scale 2016. Gabi Ogg, F. M. Gradstein. Amsterdam, Netherlands: Elsevier. ISBN 978-0-444-59468-6. OCLC 949988705.
  59. ^ a b F. M. Gradstein; James G. Ogg; Mark D. Schmitz; Gabi Ogg (2020). Geologic time scale 2020. Amsterdam, Netherlands. ISBN 978-0-12-824361-9. OCLC 1224105111.{{cite book}}: CS1 maint: location missing publisher (link)
  60. ^ Crutzen, Paul J.; Stoermer, Eugene F. (2021), Benner, Susanne; Lax, Gregor; Crutzen, Paul J.; Pöschl, Ulrich (eds.), "The 'Anthropocene' (2000)", Paul J. Crutzen and the Anthropocene: A New Epoch in Earth's History, The Anthropocene: Politik—Economics—Society—Science, Cham: Springer International Publishing, vol. 1, pp. 19–21, doi:10.1007/978-3-030-82202-6_2, ISBN 978-3-030-82201-9, S2CID 245639062, retrieved 15 April 2022
  61. ^ . Archived from the original on 7 April 2022. Retrieved 17 April 2022.
  62. ^ Subramanian, Meera (21 May 2019). "Anthropocene now: influential panel votes to recognise Earth's new epoch". Nature: d41586–019–01641–5. doi:10.1038/d41586-019-01641-5. ISSN 0028-0836. PMID 32433629. S2CID 182238145.
  63. ^ Gibbard, Philip L.; Bauer, Andrew M.; Edgeworth, Matthew; Ruddiman, William F.; Gill, Jacquelyn L.; Merritts, Dorothy J.; Finney, Stanley C.; Edwards, Lucy E.; Walker, Michael J. C.; Maslin, Mark; Ellis, Erle C. (15 November 2021). "A practical solution: the Anthropocene is a geological event, not a formal epoch". Episodes. 45 (4): 349–357. doi:10.18814/epiiugs/2021/021029. ISSN 0705-3797. S2CID 244165877.
  64. ^ Head, Martin J.; Steffen, Will; Fagerlind, David; Waters, Colin N.; Poirier, Clement; Syvitski, Jaia; Zalasiewicz, Jan A.; Barnosky, Anthony D.; Cearreta, Alejandro; Jeandel, Catherine; Leinfelder, Reinhold (15 November 2021). "The Great Acceleration is real and provides a quantitative basis for the proposed Anthropocene Series/Epoch". Episodes. 45 (4): 359–376. doi:10.18814/epiiugs/2021/021031. ISSN 0705-3797. S2CID 244145710.
  65. ^ Zalasiewicz, Jan; Waters, Colin N.; Ellis, Erle C.; Head, Martin J.; Vidas, Davor; Steffen, Will; Thomas, Julia Adeney; Horn, Eva; Summerhayes, Colin P.; Leinfelder, Reinhold; McNeill, J. R. (2021). "The Anthropocene: Comparing Its Meaning in Geology (Chronostratigraphy) with Conceptual Approaches Arising in Other Disciplines". Earth's Future. 9 (3). Bibcode:2021EaFut...901896Z. doi:10.1029/2020EF001896. ISSN 2328-4277. S2CID 233816527.
  66. ^ Bauer, Andrew M.; Edgeworth, Matthew; Edwards, Lucy E.; Ellis, Erle C.; Gibbard, Philip; Merritts, Dorothy J. (16 September 2021). "Anthropocene: event or epoch?". Nature. 597 (7876): 332. Bibcode:2021Natur.597..332B. doi:10.1038/d41586-021-02448-z. ISSN 0028-0836. PMID 34522014. S2CID 237515330.
  67. ^ Bleeker, W. (17 March 2005), Gradstein, Felix M.; Ogg, James G.; Smith, Alan G. (eds.), "Toward a "natural" Precambrian time scale", A Geologic Time Scale 2004 (1 ed.), Cambridge University Press, pp. 141–146, doi:10.1017/cbo9780511536045.011, ISBN 978-0-521-78673-7, retrieved 9 April 2022
  68. ^ Strachan, R.; Murphy, J.B.; Darling, J.; Storey, C.; Shields, G. (2020), "Precambrian (4.56–1 Ga)", Geologic Time Scale 2020, Elsevier, pp. 481–493, doi:10.1016/b978-0-12-824360-2.00016-4, ISBN 978-0-12-824360-2, S2CID 229513433, retrieved 9 April 2022
  69. ^ Van Kranendonk, Martin J. (2012). "16: A Chronostratigraphic Division of the Precambrian: Possibilities and Challenges". In Felix M. Gradstein; James G. Ogg; Mark D. Schmitz; abi M. Ogg (eds.). The geologic time scale 2012 (1st ed.). Amsterdam: Elsevier. pp. 359–365. doi:10.1016/B978-0-444-59425-9.00016-0. ISBN 978-0-44-459425-9.
  70. ^ a b c Goldblatt, C.; Zahnle, K. J.; Sleep, N. H.; Nisbet, E. G. (2010). "The Eons of Chaos and Hades". Solid Earth. 1 (1): 1–3. Bibcode:2010SolE....1....1G. doi:10.5194/se-1-1-2010.
  71. ^ Chambers, John E. (July 2004). "Planetary accretion in the inner Solar System" (PDF). Earth and Planetary Science Letters. 223 (3–4): 241–252. Bibcode:2004E&PSL.223..241C. doi:10.1016/j.epsl.2004.04.031. (PDF) from the original on 19 April 2012.
  72. ^ El Albani, Abderrazak; Bengtson, Stefan; Canfield, Donald E.; Riboulleau, Armelle; Rollion Bard, Claire; Macchiarelli, Roberto; et al. (2014). "The 2.1 Ga Old Francevillian Biota: Biogenicity, Taphonomy and Biodiversity". PLOS ONE. 9 (6): e99438. Bibcode:2014PLoSO...999438E. doi:10.1371/journal.pone.0099438. PMC 4070892. PMID 24963687.
  73. ^ El Albani, Abderrazak; Bengtson, Stefan; Canfield, Donald E.; Bekker, Andrey; Macchiarelli, Roberto; Mazurier, Arnaud; Hammarlund, Emma U.; et al. (2010). "Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago" (PDF). Nature. 466 (7302): 100–104. Bibcode:2010Natur.466..100A. doi:10.1038/nature09166. PMID 20596019. S2CID 4331375.[permanent dead link]
  74. ^ "Geological time scale". Digital Atlas of Ancient Life. Paleontological Research Institution. Retrieved 17 January 2022.
  75. ^ "Geologic Timescale Elements in the International Chronostratigraphic Chart". Retrieved 3 August 2014.
  76. ^ Cox, Simon J. D. "SPARQL endpoint for CGI timescale service". Archived from the original on 6 August 2014. Retrieved 3 August 2014.
  77. ^ Cox, Simon J. D.; Richard, Stephen M. (2014). "A geologic timescale ontology and service". Earth Science Informatics. 8: 5–19. doi:10.1007/s12145-014-0170-6. S2CID 42345393.
  78. ^ Hoag, Colin; Svenning, Jens-Christian (17 October 2017). . Annual Review of Environment and Resources. 42 (1): 27–54. doi:10.1146/annurev-environ-102016-060653. ISSN 1543-5938. Archived from the original on 1 May 2022. Retrieved 5 June 2022.
  79. ^ Bartoli, G; Sarnthein, M; Weinelt, M; Erlenkeuser, H; Garbe-Schönberg, D; Lea, D.W (2005). "Final closure of Panama and the onset of northern hemisphere glaciation". Earth and Planetary Science Letters. 237 (1–2): 33–44. Bibcode:2005E&PSL.237...33B. doi:10.1016/j.epsl.2005.06.020.
  80. ^ a b Tyson, Peter (October 2009). "NOVA, Aliens from Earth: Who's who in human evolution". PBS. Retrieved 8 October 2009.
  81. ^ Gannon, Colin (26 April 2013). "Understanding the Middle Miocene Climatic Optimum: Evaluation of Deuterium Values (δD) Related to Precipitation and Temperature". Honors Projects in Science and Technology.
  82. ^ a b c d Royer, Dana L. (2006). (PDF). Geochimica et Cosmochimica Acta. 70 (23): 5665–75. Bibcode:2006GeCoA..70.5665R. doi:10.1016/j.gca.2005.11.031. Archived from the original (PDF) on 27 September 2019. Retrieved 6 August 2015.
  83. ^ "Here's What the Last Common Ancestor of Apes and Humans Looked Like". Live Science. 10 August 2017.
  84. ^ Nengo, Isaiah; Tafforeau, Paul; Gilbert, Christopher C.; Fleagle, John G.; Miller, Ellen R.; Feibel, Craig; Fox, David L.; Feinberg, Josh; Pugh, Kelsey D.; Berruyer, Camille; Mana, Sara (2017). "New infant cranium from the African Miocene sheds light on ape evolution". Nature. 548 (7666): 169–174. Bibcode:2017Natur.548..169N. doi:10.1038/nature23456. ISSN 0028-0836. PMID 28796200. S2CID 4397839.
  85. ^ Deconto, Robert M.; Pollard, David (2003). "Rapid Cenozoic glaciation of Antarctica induced by declining atmospheric CO2" (PDF). Nature. 421 (6920): 245–249. Bibcode:2003Natur.421..245D. doi:10.1038/nature01290. PMID 12529638. S2CID 4326971.
  86. ^ Medlin, L. K.; Kooistra, W. H. C. F.; Gersonde, R.; Sims, P. A.; Wellbrock, U. (1997). "Is the origin of the diatoms related to the end-Permian mass extinction?". Nova Hedwigia. 65 (1–4): 1–11. doi:10.1127/nova.hedwigia/65/1997/1. hdl:10013/epic.12689.
  87. ^ Williams, Joshua J.; Mills, Benjamin J. W.; Lenton, Timothy M. (2019). "A tectonically driven Ediacaran oxygenation event". Nature Communications. 10 (1): 2690. Bibcode:2019NatCo..10.2690W. doi:10.1038/s41467-019-10286-x. ISSN 2041-1723. PMC 6584537. PMID 31217418.
  88. ^ Naranjo-Ortiz, Miguel A.; Gabaldón, Toni (25 April 2019). "Fungal evolution: major ecological adaptations and evolutionary transitions". Biological Reviews of the Cambridge Philosophical Society. Cambridge Philosophical Society (Wiley). 94 (4): 1443–1476. doi:10.1111/brv.12510. ISSN 1464-7931. PMC 6850671. PMID 31021528. S2CID 131775942.
  89. ^ Žárský, Jakub; Žárský, Vojtěch; Hanáček, Martin; Žárský, Viktor (27 January 2022). "Cryogenian Glacial Habitats as a Plant Terrestrialisation Cradle – The Origin of the Anydrophytes and Zygnematophyceae Split". Frontiers in Plant Science. 12: 735020. doi:10.3389/fpls.2021.735020. ISSN 1664-462X. PMC 8829067. PMID 35154170.
  90. ^ Yoon, Hwan Su; Hackett, Jeremiah D.; Ciniglia, Claudia; Pinto, Gabriele; Bhattacharya, Debashish (2004). "A Molecular Timeline for the Origin of Photosynthetic Eukaryotes". Molecular Biology and Evolution. 21 (5): 809–818. doi:10.1093/molbev/msh075. ISSN 1537-1719. PMID 14963099.
  91. ^ Bowring, Samuel A.; Williams, Ian S. (1999). "Priscoan (4.00–4.03 Ga) orthogneisses from northwestern Canada". Contributions to Mineralogy and Petrology. 134 (1): 3. Bibcode:1999CoMP..134....3B. doi:10.1007/s004100050465. S2CID 128376754.
  92. ^ Iizuka, Tsuyoshi; Komiya, Tsuyoshi; Maruyama, Shigenori (2007), "Chapter 3.1 The Early Archean Acasta Gneiss Complex: Geological, Geochronological and Isotopic Studies and Implications for Early Crustal Evolution", Developments in Precambrian Geology, Elsevier, vol. 15, pp. 127–147, doi:10.1016/s0166-2635(07)15031-3, ISBN 978-0-444-52810-0, retrieved 1 May 2022
  93. ^ Wilde, Simon A.; Valley, John W.; Peck, William H.; Graham, Colin M. (2001). "Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago". Nature. 409 (6817): 175–178. doi:10.1038/35051550. ISSN 0028-0836. PMID 11196637. S2CID 4319774.
  94. ^ Wilhelms, Don E. (1987). The geologic history of the Moon. Professional Paper. United States Geological Survey. doi:10.3133/pp1348.
  95. ^ Tanaka, Kenneth L. (1986). "The stratigraphy of Mars". Journal of Geophysical Research. 91 (B13): E139. Bibcode:1986JGR....91E.139T. doi:10.1029/JB091iB13p0E139. ISSN 0148-0227.
  96. ^ Carr, Michael H.; Head, James W. (1 June 2010). "Geologic history of Mars". Earth and Planetary Science Letters. Mars Express after 6 Years in Orbit: Mars Geology from Three-Dimensional Mapping by the High Resolution Stereo Camera (HRSC) Experiment. 294 (3): 185–203. Bibcode:2010E&PSL.294..185C. doi:10.1016/j.epsl.2009.06.042. ISSN 0012-821X.
  97. ^ Bibring, Jean-Pierre; Langevin, Yves; Mustard, John F.; Poulet, François; Arvidson, Raymond; Gendrin, Aline; Gondet, Brigitte; Mangold, Nicolas; Pinet, P.; Forget, F.; Berthé, Michel (21 April 2006). "Global Mineralogical and Aqueous Mars History Derived from OMEGA/Mars Express Data". Science. 312 (5772): 400–404. Bibcode:2006Sci...312..400B. doi:10.1126/science.1122659. ISSN 0036-8075. PMID 16627738. S2CID 13968348.

Further reading Edit

  • Aubry, Marie-Pierre; Van Couvering, John A.; Christie-Blick, Nicholas; Landing, Ed; Pratt, Brian R.; Owen, Donald E.; Ferrusquia-Villafranca, Ismael (2009). "Terminology of geological time: Establishment of a community standard". Stratigraphy. 6 (2): 100–105. doi:10.7916/D8DR35JQ.
  • Gradstein, F. M.; Ogg, J. G. (2004). (PDF). Lethaia. 37 (2): 175–181. doi:10.1080/00241160410006483. Archived from the original (PDF) on 17 April 2018. Retrieved 30 November 2018.
  • Gradstein, Felix M.; Ogg, James G.; Smith, Alan G. (2004). A Geologic Time Scale 2004. Cambridge, UK: Cambridge University Press. ISBN 978-0-521-78142-8. Retrieved 18 November 2011.
  • Gradstein, Felix M.; Ogg, James G.; Smith, Alan G.; Bleeker, Wouter; Laurens, Lucas, J. (June 2004). "A new Geologic Time Scale, with special reference to Precambrian and Neogene". Episodes. 27 (2): 83–100. doi:10.18814/epiiugs/2004/v27i2/002.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  • Ialenti, Vincent (28 September 2014). "Embracing 'Deep Time' Thinking". NPR. NPR Cosmos & Culture.
  • Ialenti, Vincent (21 September 2014). "Pondering 'Deep Time' Could Inspire New Ways To View Climate Change". NPR. NPR Cosmos & Culture.
  • Knoll, Andrew H.; Walter, Malcolm R.; Narbonne, Guy M.; Christie-Blick, Nicholas (30 July 2004). "A New Period for the Geologic Time Scale" (PDF). Science. 305 (5684): 621–622. doi:10.1126/science.1098803. PMID 15286353. S2CID 32763298. (PDF) from the original on 15 December 2011. Retrieved 18 November 2011.
  • Levin, Harold L. (2010). "Time and Geology". The Earth Through Time. Hoboken, New Jersey: John Wiley & Sons. ISBN 978-0-470-38774-0. Retrieved 18 November 2011.
  • Montenari, Michael (2016). Stratigraphy and Timescales (1st ed.). Amsterdam: Academic Press (Elsevier). ISBN 978-0-12-811549-7.
  • Montenari, Michael (2017). Advances in Sequence Stratigraphy (1st ed.). Amsterdam: Academic Press (Elsevier). ISBN 978-0-12-813077-3.
  • Montenari, Michael (2018). Cyclostratigraphy and Astrochronology (1st ed.). Amsterdam: Academic Press (Elsevier). ISBN 978-0-12-815098-6.
  • Montenari, Michael (2019). Case Studies in Isotope Stratigraphy (1st ed.). Amsterdam: Academic Press (Elsevier). ISBN 978-0-12-817552-1.
  • Montenari, Michael (2020). Carbon Isotope Stratigraphy (1st ed.). Amsterdam: Academic Press (Elsevier). ISBN 978-0-12-820991-2.
  • Montenari, Michael (2021). Calcareous Nannofossil Biostratigraphy (1st ed.). Amsterdam: Academic Press (Elsevier). ISBN 978-0-12-824624-5.
  • Nichols, Gary (2013). Sedimentology and Stratigraphy (2nd ed.). Hoboken: Wiley-Blackwell. ISBN 978-1-4051-3592-4
  • Williams, Aiden (2019). Sedimentology and Stratigraphy (1st ed.). Forest Hills, NY: Callisto Reference. ISBN 978-1-64116-075-9

External links Edit

 
Wikimedia Commons has media related to Geologic time scale.
 
The Wikibook Historical Geology has a page on the topic of: Geological column
  • The current version of the International Chronostratigraphic Chart can be found at stratigraphy.org/chart
  • Interactive version of the International Chronostratigraphic Chart is found at stratigraphy.org/timescale
  • A list of current Global Boundary Stratotype and Section Points is found at stratigraphy.org/gssps
  • (archived 18 April 2005)
  • (archived 20 January 2019)
  • British Geological Survey: Geological Timechart
  • (archived 23 June 2004)
  • (archived 11 November 2005)
  • SeeGrid: Geological Time Systems. 23 July 2008 at the Wayback Machine. Information model for the geologic time scale.
  • Exploring Time from Planck Time to the lifespan of the universe
  • , Gradstein, Felix M. et al. (2004) A new Geologic Time Scale, with special reference to Precambrian and Neogene, Episodes, Vol. 27, no. 2 June 2004 (pdf)
  • Lane, Alfred C, and Marble, John Putman 1937. Report of the Committee on the measurement of geologic time
  • (archived 14 July 2011)
  • Deep Time – A History of the Earth : Interactive Infographic
  • Geology Buzz: Geologic Time Scale. 12 August 2021 at the Wayback Machine.

October 19, 2023
geologic, time, scale, geologic, time, scale, geological, time, scale, representation, time, based, rock, record, earth, system, chronological, dating, that, uses, chronostratigraphy, process, relating, strata, time, geochronology, scientific, branch, geology,. 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 geochronology a scientific branch of geology that aims to determine the age of rocks It is used primarily by Earth scientists including geologists paleontologists geophysicists geochemists and paleoclimatologists to describe the timing and relationships of events in geologic history The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as lithologies paleomagnetic properties and fossils The definition of standardised international units of geologic time is the responsibility of the International Commission on Stratigraphy ICS a constituent body of the International Union of Geological Sciences IUGS whose primary objective 1 is to precisely define global chronostratigraphic units of the International Chronostratigraphic Chart ICC 2 that are used to define divisions of geologic time The chronostratigraphic divisions are in turn used to define geochronologic units 2 Geologic time scale with proportional representation of eons eonothems and eras erathems Cenozoic is abbreviated to Cz The image also shows some notable events in Earth s history and the general evolution of life A megannus Ma represents one million 106 years Alternate representation of the geologic time scale represented as a clock Note the GTS is linear and not cyclic While some regional terms are still in use 3 the table of geologic time presented in this article conforms to the nomenclature ages and colour codes set forth by the ICS 1 4 Contents 1 Principles 2 Terminology 2 1 Divisions of geologic time 3 Naming of geologic time 4 History of the geologic time scale 4 1 Early history 4 2 Establishment of primary principles 4 3 Formulation of a modern geologic time scale 4 4 The advent of geochronometry 4 5 Modern international geologic time scale 5 Major proposed revisions to the ICC 5 1 Proposed Anthropocene Series Epoch 5 2 Proposals for revisions to pre Cryogenian timeline 5 2 1 Shields et al 2021 5 2 2 Van Kranendonk et al 2012 GTS2012 6 Table of geologic time 7 Non Earth based geologic time scales 7 1 Lunar selenological time scale 7 2 Martian geologic time scale 8 See also 9 Notes 10 References 11 Further reading 12 External linksPrinciples EditSee also Age of Earth History of Earth and Geological history of Earth This section needs additional citations for verification Please help improve this article by adding citations to reliable sources in this section Unsourced material may be challenged and removed August 2023 Learn how and when to remove this template message The geologic time scale is a way of representing deep time based on events that have occurred throughout Earth s history a time span of about 4 54 0 05 Ga 4 54 billion years 5 It chronologically organises strata and subsequently time by observing fundamental changes in stratigraphy that correspond to major geological or paleontological events For example the Cretaceous Paleogene extinction event marks the lower boundary of the Paleogene System Period and thus the boundary between the Cretaceous and Paleogene Systems Periods For divisions prior to the Cryogenian arbitrary numeric boundary definitions Global Standard Stratigraphic Ages GSSAs are used to divide geologic time Proposals have been made to better reconcile these divisions with the rock record 6 3 Historically regional geologic time scales were used 3 due to the litho and biostratigraphic differences around the world in time equivalent rocks The ICS has long worked to reconcile conflicting terminology by standardising globally significant and identifiable stratigraphic horizons that can be used to define the lower boundaries of chronostratigraphic units Defining chronostratigraphic units in such a manner allows for the use of global standardised nomenclature The ICC represents this ongoing effort The relative relationships of rocks for determining their chronostratigraphic positions use the overriding principles of citation needed Superposition Newer rock beds will lie on top of older rock beds unless the succession has been overturned Horizontality All rock layers were originally deposited horizontally note 1 Lateral continuity Originally deposited layers of rock extend laterally in all directions until either thinning out or being cut off by a different rock layer Biologic succession where applicable This states that each stratum in a succession contains a distinctive set of fossils This allows for a correlation of the stratum even when the horizon between them is not continuous Cross cutting relationships A rock feature that cuts across another feature must be younger than the rock it cuts across Inclusion Small fragments of one type of rock but embedded in a second type of rock must have formed first and were included when the second rock was forming Relationships of unconformities Geologic features representing periods of erosion or non deposition indicating non continuous sediment deposition Terminology EditSee also Stratigraphy Chronostratigraphy Biostratigraphy Magnetostratigraphy Lithostratigraphy and Geochronology The GTS is divided into chronostratigraphic units and their corresponding geochronologic units These are represented on the ICC published by the ICS however regional terms are still in use in some areas Chronostratigraphy is the element of stratigraphy that deals with the relation between rock bodies and the relative measurement of geological time 7 It is the process where distinct strata between defined stratigraphic horizons are assigned to represent a relative interval of geologic time A chronostratigraphic unit is a body of rock layered or unlayered that is defined between specified stratigraphic horizons which represent specified intervals of geologic time They include all rocks representative of a specific interval of geologic time and only this time span 7 Eonothem erathem system series subseries stage and substage are the hierarchical chronostratigraphic units 7 Geochronology is the scientific branch of geology that aims to determine the age of rocks fossils and sediments either through absolute e g radiometric dating or relative means e g stratigraphic position Paleomagnetism stable isotope ratios 8 A geochronologic unit is a subdivision of geologic time It is a numeric representation of an intangible property time 8 Eon era period epoch subepoch age and subage are the hierarchical geochronologic units 7 Geochronometry is the field of geochronology that numerically quantifies geologic time 8 A Global Boundary Stratotype Section and Point GSSP is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundaries of stages on the geologic time scale 9 Recently this has been used to define the base of a system 10 A Global Standard Stratigraphic Age GSSA 11 is a numeric only chronologic reference point used to define the base of geochronologic units prior to the Cryogenian These points are arbitrarily defined 7 They are used where GSSPs have not yet been established Research is ongoing to define GSSPs for the base of all units that are currently defined by GSSAs The numeric geochronometric representation of a geochronologic unit can and is more often subject to change when geochronology refines the geochronometry while the equivalent chronostratigraphic unit remains the same and their revision is less common For example in early 2022 the boundary between the Ediacaran and Cambrian Periods geochronologic units was revised from 541 Ma to 538 8 Ma but the rock definition of the boundary GSSP at the base of the Cambrian and thus the boundary between the Ediacaran and Cambrian Systems chronostratigraphic units has not changed merely the geochronometry has been refined The numeric values on the ICC are represented by the unit Ma megaannum meaning million years i e 201 4 0 2 Ma the lower boundary of the Jurassic Period is defined as 201 400 000 years old with an uncertainty of 200 000 years Other SI prefix units commonly used by geologists are Ga gigaannum billion years and ka kiloannum thousand years with the latter often represented in calibrated units before present Divisions of geologic time Edit An eon is the largest formal geochronologic time unit and is the equivalent of a chronostratigraphic eonothem 12 As of October 2022 update there are four formally defined eons eonothems the Hadean Archean Proterozoic and Phanerozoic 2 An era is the second largest geochronologic time unit and is the equivalent of a chronostratigraphic erathem 7 12 As of April 2022 update there are currently ten defined eras erathems 2 namely the Eoarchean Paleoarchean Mesoarchean Neoarchean Paleoproterozoic Mesoproterozoic Neoproterozoic Paleozoic Mesozoic and Cenozoic with none from the Hadean eon A period is a major rank below an era and above an epoch It is the geochronologic equivalent of a chronostratigraphic system 7 12 As of April 2022 update there are currently 22 defined periods systems 2 As an exception two subperiods subsystems are used for the Carboniferous Period System 7 An epoch is the second smallest geochronologic unit between a period and an age It is the equivalent of a chronostratigraphic series 7 12 As of April 2022 update there are currently 37 defined and one informal epochs series There are also 11 subepochs subseries which are all within the Neogene and Quaternary 2 The use of subseries subepochs as formal ranks units in international chronostratigraphy was ratified in 2022 13 An age is the smallest hierarchical geochronologic unit and is the equivalent of a chronostratigraphic stage 7 12 As of April 2022 update there are currently 96 formal and five informal ages stages 2 A chron is a non hierarchical formal geochronology unit of unspecified rank and is the equivalent of a chronostratigraphic chronozone 7 These correlate with magnetostratigraphic lithostratigraphic or biostratigraphic units as they are based on previously defined stratigraphic units or geologic features The Early and Late subdivisions are used as the geochronologic equivalents of the chronostratigraphic Lower and Upper e g Early Triassic Period geochronologic unit is used in place of Lower Triassic Series chronostratigraphic unit In essence it is true to say that rocks representing a given chronostratigraphic unit are that chronostratigraphic unit and the time they were laid down in is the geochronologic unit i e the rocks that represent the Silurian Series are the Silurian Series and they were deposited during the Silurian Period Formal hierarchical units of the geologic time scale largest to smallest Chronostratigraphic unit strata Geochronologic unit time Time span note 2 Eonothem Eon Several hundred million years to two billion yearsErathem Era Tens to hundreds of millions of yearsSystem Period Millions of years to tens of millions of yearsSeries Epoch Hundreds of thousands of years to tens of millions of yearsSubseries Subepoch Thousands of years to millions of yearsStage Age Thousands of years to millions of yearsNaming of geologic time EditThe names of geologic time units are defined for chronostratigraphic units with the corresponding geochronologic unit sharing the same name with a change to the latter e g Phanerozoic Eonothem becomes the Phanerozoic Eon Names of erathems in the Phanerozoic were chosen to reflect major changes in the history of life on Earth Paleozoic old life Mesozoic middle life and Cenozoic new life Names of systems are diverse in origin with some indicating chronologic position e g Paleogene while others are named for lithology e g Cretaceous geography e g Permian or are tribal e g Ordovician in origin Most currently recognised series and subseries are named for their position within a system series early middle late however the ICS advocates for all new series and subseries to be named for a geographic feature in the vicinity of its stratotype or type locality The name of stages should also be derived from a geographic feature in the locality of its stratotype or type locality 7 Informally the time before the Cambrian is often referred to as the Precambrian or pre Cambrian Supereon 6 note 3 Time span and etymology of eonothem eon names Name Time Span Duration million years Etymology of namePhanerozoic 538 8 to 0 million years ago 538 8 From the Greek words faneros phaneros meaning visible or abundant and zwh zoe meaning life Proterozoic 2 500 to 538 8 million years ago 1961 2 From the Greek words proteros proteros meaning former or earlier and zwh zoe meaning life Archean 4 000 to 2 500 million years ago 1500 From the Greek word arxh arche meaning beginning origin Hadean 4 567 3 to 4 000 million years ago 567 3 From Hades Greek ᾍdhs translit Haides the god of the underworld hell the inferno in Greek mythology Time span and etymology of erathem era names Name Time Span Duration million years Etymology of nameCenozoic 66 to 0 million years ago 66 From the Greek words kainos kainos meaning new and zwh zōḗ meaning life Mesozoic 251 9 to 66 million years ago 185 902 From the Greek words meso meso meaning middle and zwh zōḗ meaning life Paleozoic 538 8 to 251 9 million years ago 286 898 From the Greek words palios palaios meaning old and zwh zōḗ meaning life Neoproterozoic 1 000 to 538 8 million years ago 461 2 From the Greek words neos neos meaning new or young proteros proteros meaning former or earlier and zwh zōḗ meaning life Mesoproterozoic 1 600 to 1 000 million years ago 600 From the Greek words meso meso meaning middle proteros proteros meaning former or earlier and zwh zōḗ meaning life Paleoproterozoic 2 500 to 1 600 million years ago 900 From the Greek words palios palaios meaning old proteros proteros meaning former or earlier and zwh zōḗ meaning life Neoarchean 2 800 to 2 500 million years ago 300 From the Greek words neos neos meaning new or young and ἀrxaῖos arkhaios meaning ancient Mesoarchean 3 200 to 2 800 million years ago 400 From the Greek words meso meso meaning middle and ἀrxaῖos arkhaios meaning ancient Paleoarchean 3 600 to 3 200 million years ago 400 From the Greek words palios palaios meaning old and ἀrxaῖos arkhaios meaning ancient Eoarchean 4 000 to 3 600 million years ago 400 From the Greek words Hws Eṓs meaning dawn and ἀrxaῖos arkhaios meaning ancient Time span and etymology of system period names Name Time Span Duration million years Etymology of nameQuaternary 2 6 to 0 million years ago 2 58 First introduced by Jules Desnoyers in 1829 for sediments in France s Seine Basin that appeared to be younger than Tertiary note 4 rocks 14 Neogene 23 to 2 6 million years ago 20 45 Derived from the Greek words neos neos meaning new and genea genea meaning genesis or birth Paleogene 66 to 23 million years ago 42 97 Derived from the Greek words palios palaios meaning old and genea genea meaning genesis or birth Cretaceous 145 to 66 million years ago 79 Derived from Terrain Cretace used in 1822 by Jean d Omalius d Halloy in reference to extensive beds of chalk within the Paris Basin 15 Ultimately derived from the Latin creta meaning chalk Jurassic 201 4 to 145 million years ago 56 4 Named after the Jura Mountains Originally used by Alexander von Humboldt as Jura Kalkstein Jura limestone in 1799 16 Alexandre Brongniart was the first to publish the term Jurassic in 1829 17 18 Triassic 251 9 to 201 4 million years ago 50 502 From the Trias of Friedrich August von Alberti in reference to a trio of formations widespread in southern Germany Permian 298 9 to 251 9 million years ago 46 998 Named after the historical region of Perm Russian Empire 19 Carboniferous 358 9 to 298 9 million years ago 60 Means coal bearing from the Latin carbō coal and ferō to bear carry 20 Devonian 419 2 to 358 9 million years ago 60 3 Named after Devon England 21 Silurian 443 8 to 419 2 million years ago 24 6 Named after the Celtic tribe the Silures 22 Ordovician 485 4 to 443 8 million years ago 41 6 Named after the Celtic tribe Ordovices 23 24 Cambrian 538 8 to 485 4 million years ago 53 4 Named for Cambria a latinised form of the Welsh name for Wales Cymru 25 Ediacaran 635 to 538 8 million years ago 96 2 Named for the Ediacara Hills Ediacara is possibly a corruption of the Kuyani words Yata Takarra meaning hard or stony ground 26 27 Cryogenian 720 to 635 million years ago 85 From the Greek words kryos kryos meaning cold and genesis genesis meaning birth 3 Tonian 1 000 to 720 million years ago 280 From the Greek word tonos tonos meaning stretch 3 Stenian 1 200 to 1 000 million years ago 200 From the Greek word stenos stenos meaning narrow 3 Ectasian 1 400 to 1 200 million years ago 200 From the Greek word ἔktᾰsῐs ektasis meaning extension 3 Calymmian 1 600 to 1 400 million years ago 200 From the Greek word kalymmᾰ kalumma meaning cover 3 Statherian 1 800 to 1 600 million years ago 200 From the Greek word sta8eros statheros meaning stable 3 Orosirian 2 050 to 1 800 million years ago 250 From the Greek word ὀroseira oroseira meaning mountain range 3 Rhyacian 2 300 to 2 050 million years ago 250 From the Greek word ῥya3 rhyax meaning stream of lava 3 Siderian 2 500 to 2 300 million years ago 200 From the Greek word sidhros sideros meaning iron 3 History of the geologic time scale EditSee also History of geology and History of paleontology Early history Edit While a modern geological time scale was not formulated until 1911 28 by Arthur Holmes the broader concept that rocks and time are related can be traced back to at least the philosophers of Ancient Greece Xenophanes of Colophon c 570 487 BCE observed rock beds with fossils of shells located above the sea level viewed them as once living organisms and used this to imply an unstable relationship in which the sea had at times transgressed over the land and at other times had regressed 29 This view was shared by a few of Xenophanes contemporaries and those that followed including Aristotle 384 322 BCE who with additional observations reasoned that the positions of land and sea had changed over long periods of time The concept of deep time was also recognised by Chinese naturalist Shen Kuo 30 1031 1095 and Islamic scientist philosophers notably the Brothers of Purity who wrote on the processes of stratification over the passage of time in their treatises 29 Their work likely inspired that of the 11th century Persian polymath Avicenna Ibn Sina 980 1037 who wrote in The Book of Healing 1027 on the concept of stratification and superposition pre dating Nicolas Steno by more than six centuries 29 Avicenna also recognised fossils as petrifications of the bodies of plants and animals 31 with the 13th century Dominican bishop Albertus Magnus c 1200 1280 extending this into a theory of a petrifying fluid 32 verification needed These works appeared to have little influence on scholars in Medieval Europe who looked to the Bible to explain the origins of fossils and sea level changes often attributing these to the Deluge including Ristoro d Arezzo in 1282 29 It was not until the Italian Renaissance when Leonardo da Vinci 1452 1519 would reinvigorate the relationships between stratification relative sea level change and time denouncing attribution of fossils to the Deluge 33 29 Of the stupidity and ignorance of those who imagine that these creatures were carried to such places distant from the sea by the Deluge Why do we find so many fragments and whole shells between the different layers of stone unless they had been upon the shore and had been covered over by earth newly thrown up by the sea which then became petrified And if the above mentioned Deluge had carried them to these places from the sea you would find the shells at the edge of one layer of rock only not at the edge of many where may be counted the winters of the years during which the sea multiplied the layers of sand and mud brought down by the neighboring rivers and spread them over its shores And if you wish to say that there must have been many deluges in order to produce these layers and the shells among them it would then become necessary for you to affirm that such a deluge took place every year These views of da Vinci remained unpublished and thus lacked influence at the time however questions of fossils and their significance were pursued and while views against Genesis were not readily accepted and dissent from religious doctrine was in some places unwise scholars such as Girolamo Fracastoro shared da Vinci s views and found the attribution of fossils to the Deluge absurd 29 Establishment of primary principles Edit Niels Stensen more commonly known as Nicolas Steno 1638 1686 is credited with establishing four of the guiding principles of stratigraphy 29 In De solido intra solidum naturaliter contento dissertationis prodromus Steno states 34 35 When any given stratum was being formed all the matter resting on it was fluid and therefore when the lowest stratum was being formed none of the upper strata existed strata which are either perpendicular to the horizon or inclined to it were at one time parallel to the horizon When any given stratum was being formed it was either encompassed at its edges by another solid substance or it covered the whole globe of the earth Hence it follows that wherever bared edges of strata are seen either a continuation of the same strata must be looked for or another solid substance must be found that kept the material of the strata from being dispersed If a body or discontinuity cuts across a stratum it must have formed after that stratum Respectively these are the principles of superposition original horizontality lateral continuity and cross cutting relationships From this Steno reasoned that strata were laid down in succession and inferred relative time in Steno s belief time from Creation While Steno s principles were simple and attracted much attention applying them proved challenging 29 These basic principles albeit with improved and more nuanced interpretations still form the foundational principles of determining the correlation of strata relative to geologic time Over the course of the 18th century geologists realised that Sequences of strata often become eroded distorted tilted or even inverted after deposition Strata laid down at the same time in different areas could have entirely different appearances The strata of any given area represented only part of Earth s long historyFormulation of a modern geologic time scale Edit The apparent earliest formal division of the geologic record with respect to time was introduced by Thomas Burnet who applied a two fold terminology to mountains by identifying montes primarii for rock formed at the time of the Deluge and younger monticulos secundarios formed later from the debris of the primarii 36 29 This attribution to the Deluge while questioned earlier by the likes of da Vinci was the foundation of Abraham Gottlob Werner s 1749 1817 Neptunism theory in which all rocks precipitated out of a single flood 37 A competing theory Plutonism was developed by Anton Moro 1687 1784 and also used primary and secondary divisions for rock units 38 29 In this early version of the Plutonism theory the interior of Earth was seen as hot and this drove the creation of primary igneous and metamorphic rocks and secondary rocks formed contorted and fossiliferous sediments These primary and secondary divisions were expanded on by Giovanni Targioni Tozzetti 1712 1783 and Giovanni Arduino 1713 1795 to include tertiary and quaternary divisions 29 These divisions were used to describe both the time during which the rocks were laid down and the collection of rocks themselves i e it was correct to say Tertiary rocks and Tertiary Period Only the Quaternary division is retained in the modern geologic time scale while the Tertiary division was in use until the early 21st century The Neptunism and Plutonism theories would compete into the early 19th century with a key driver for resolution of this debate being the work of James Hutton 1726 1797 in particular his Theory of the Earth first presented before the Royal Society of Edinburgh in 1785 39 40 41 Hutton s theory would later become known as uniformitarianism popularised by John Playfair 42 1748 1819 and later Charles Lyell 1797 1875 in his Principles of Geology 43 44 45 Their theories strongly contested the 6 000 year age of the Earth as suggested determined by James Ussher via Biblical chronology that was accepted at the time by western religion Instead using geological evidence they contested Earth to be much older cementing the concept of deep time During the early 19th century William Smith Georges Cuvier Jean d Omalius d Halloy and Alexandre Brongniart pioneered the systematic division of rocks by stratigraphy and fossil assemblages These geologists began to use the local names given to rock units in a wider sense correlating strata across national and continental boundaries based on their similarity to each other Many of the names below erathem era rank in use on the modern ICC GTS were determined during the early to mid 19th century The advent of geochronometry Edit During the 19th century the debate regarding Earth s age was renewed with geologists estimating ages based on denudation rates and sedimentary thicknesses or ocean chemistry and physicists determining ages for the cooling of the Earth or the Sun using basic thermodynamics or orbital physics 5 These estimations varied from 15 000 million years to 0 075 million years depending on method and author but the estimations of Lord Kelvin and Clarence King were held in high regard at the time due to their pre eminence in physics and geology All of these early geochronometric determinations would later prove to be incorrect The discovery of radioactive decay by Henri Becquerel Marie Curie and Pierre Curie laid the ground work for radiometric dating but the knowledge and tools required for accurate determination of radiometric ages would not be in place until the mid 1950s 5 Early attempts at determining ages of uranium minerals and rocks by Ernest Rutherford Bertram Boltwood Robert Strutt and Arthur Holmes would culminate in what are considered the first international geological time scales by Holmes in 1911 and 1913 28 46 47 The discovery of isotopes in 1913 48 by Frederick Soddy and the developments in mass spectrometry pioneered by Francis William Aston Arthur Jeffrey Dempster and Alfred O C Nier during the early to mid 20th century would finally allow for the accurate determination of radiometric ages with Holmes publishing several revisions to his geological time scale with his final version in 1960 5 47 49 50 Modern international geologic time scale Edit The establishment of the IUGS in 1961 51 and acceptance of the Commission on Stratigraphy applied in 1965 52 to become a member commission of IUGS led to the founding of the ICS One of the primary objectives of the ICS is the establishment publication and revision of the ICS International Chronostratigraphic Chart which is the standard reference global Geological Time Scale to include the ratified Commission decisions 1 Following on from Holmes several A Geological Time Scale books were published in 1982 53 1989 54 2004 55 2008 56 2012 57 2016 58 and 2020 59 However since 2013 the ICS has taken responsibility for producing and distributing the ICC citing the commercial nature independent creation and lack of oversight by the ICS on the prior published GTS versions GTS books prior to 2013 although these versions were published in close association with the ICS 2 Subsequent Geologic Time Scale books 2016 58 and 2020 59 are commercial publications with no oversight from the ICS and do not entirely conform to the chart produced by the ICS The ICS produced GTS charts are versioned year month beginning at v2013 01 At least one new version is published each year incorporating any changes ratified by the ICS since the prior version The following five timelines show the geologic time scale to scale The first shows the entire time from the formation of the Earth to the present but this gives little space for the most recent eon The second timeline shows an expanded view of the most recent eon In a similar way the most recent era is expanded in the third timeline the most recent period is expanded in the fourth timeline and the most recent epoch is expanded in the fifth timeline Millions of Years 1st 2nd 3rd and 4th Thousands of years 5th Major proposed revisions to the ICC EditProposed Anthropocene Series Epoch Edit Main article Anthropocene First suggested in 2000 60 the Anthropocene is a proposed epoch series for the most recent time in Earth s history While still informal it is a widely used term to denote the present geologic time interval in which many conditions and processes on Earth are profoundly altered by human impact 61 As of April 2022 update the Anthropocene has not been ratified by the ICS however in May 2019 the Anthropocene Working Group voted in favour of submitting a formal proposal to the ICS for the establishment of the Anthropocene Series Epoch 62 Nevertheless the definition of the Anthropocene as a geologic time period rather than a geologic event remains controversial and difficult 63 64 65 66 Proposals for revisions to pre Cryogenian timeline Edit Shields et al 2021 Edit An international working group of the ICS on pre Cryogenian chronostratigraphic subdivision have outlined a template to improve the pre Cryogenian geologic time scale based on the rock record to bring it in line with the post Tonian geologic time scale 6 This work assessed the geologic history of the currently defined eons and eras of the pre Cambrian note 3 and the proposals in the Geological Time Scale books 2004 67 2012 3 and 2020 68 Their recommend revisions 6 of the pre Cryogenian geologic time scale were changes from the current scale v2022 10 are italicised Three divisions of the Archean instead of four by dropping Eoarchean and revisions to their geochronometric definition along with the repositioning of the Siderian into the latest Neoarchean and a potential Kratian division in the Neoarchean Archean 4000 2450 Ma Paleoarchean 4000 3500 Ma Mesoarchean 3500 3000 Ma Neoarchean 3000 2450 Ma Kratian no fixed time given prior to the Siderian from Greek word kratos kratos meaning strength Siderian 2450 Ma moved from Proterozoic to end of Archean no start time given base of Paleoproterozoic defines the end of the Siderian Refinement of geochronometric divisions of the Proterozoic Paleoproterozoic repositioning of the Statherian into the Mesoproterozoic new Skourian period system in the Paleoproterozoic new Kleisian or Syndian period system in the Neoproterozoic Paleoproterozoic 2450 1800 Ma Skourian 2450 2300 Ma from the Greek word skoyria skouria meaning rust Rhyacian 2300 2050 Ma Orosirian 2050 1800 Ma Mesoproterozoic 1800 1000 Ma Statherian 1800 1600 Ma Calymmian 1600 1400 Ma Ectasian 1400 1200 Ma Stenian 1200 1000 Ma Neoproterozoic 1000 538 8 Ma note 5 Kleisian or Syndian 1000 800 Ma respectively from the Greek words kleisimo kleisimo meaning closure and syndesh syndesi meaning connection Tonian 800 720 Ma Cryogenian 720 635 Ma Ediacaran 635 538 8 Ma Proposed pre Cambrian timeline Shield et al 2021 ICS working group on pre Cryogenian chronostratigraphy shown to scale note 6 Current ICC pre Cambrian timeline v2022 10 shown to scale Van Kranendonk et al 2012 GTS2012 Edit The book Geologic Time Scale 2012 was the last commercial publication of an international chronostratigraphic chart that was closely associated with the ICS 2 It included a proposal to substantially revise the pre Cryogenian time scale to reflect important events such as the formation of the solar system and the Great Oxidation Event among others while at the same time maintaining most of the previous chronostratigraphic nomenclature for the pertinent time span 69 As of April 2022 update these proposed changes have not been accepted by the ICS The proposed changes changes from the current scale v2022 10 are italicised Hadean Eon 4567 4030 Ma Chaotian Era Erathem 4567 4404 Ma the name alluding both to the mythological Chaos and the chaotic phase of planet formation 57 70 71 Jack Hillsian or Zirconian Era Erathem 4404 4030 Ma both names allude to the Jack Hills Greenstone Belt which provided the oldest mineral grains on Earth zircons 57 70 Archean Eon Eonothem 4030 2420 Ma Paleoarchean Era Erathem 4030 3490 Ma Acastan Period System 4030 3810 Ma named after the Acasta Gneiss one of the oldest preserved pieces of continental crust 57 70 Isuan Period 3810 3490 Ma named after the Isua Greenstone Belt 57 Mesoarchean Era Erathem 3490 2780 Ma Vaalbaran Period System 3490 3020 Ma based on the names of the Kapvaal Southern Africa and Pilbara Western Australia cratons to reflect the growth of stable continental nuclei or proto cratonic kernels 57 Pongolan Period System 3020 2780 Ma named after the Pongola Supergroup in reference to the well preserved evidence of terrestrial microbial communities in those rocks 57 Neoarchean Era Erathem 2780 2420 Ma Methanian Period System 2780 2630 Ma named for the inferred predominance of methanotrophic prokaryotes 57 Siderian Period System 2630 2420 Ma named for the voluminous banded iron formations formed within its duration 57 Proterozoic Eon Eonothem 2420 538 8 Ma note 5 Paleoproterozoic Era Erathem 2420 1780 Ma Oxygenian Period System 2420 2250 Ma named for displaying the first evidence for a global oxidising atmosphere 57 Jatulian or Eukaryian Period System 2250 2060 Ma names are respectively for the Lomagundi Jatuli d13C isotopic excursion event spanning its duration and for the proposed 72 73 first fossil appearance of eukaryotes 57 Columbian Period System 2060 1780 Ma named after the supercontinent Columbia 57 Mesoproterozoic Era Erathem 1780 850 Ma Rodinian Period System 1780 850 Ma named after the supercontinent Rodinia stable environment 57 Proposed pre Cambrian timeline GTS2012 shown to scale Current ICC pre Cambrian timeline v2022 10 shown to scale Table of geologic time EditThe following table summarises the major events and characteristics of the divisions making up the geologic time scale of Earth This table is arranged with the most recent geologic periods at the top and the oldest at the bottom The height of each table entry does not correspond to the duration of each subdivision of time As such this table is not to scale and does not accurately represent the relative time spans of each geochronologic unit While the Phanerozoic Eon looks longer than the rest it merely spans 539 million years 12 of Earth s history whilst the previous three eons note 3 collectively span 3 461 million years 76 of Earth s history This bias toward the most recent eon is in part due to the relative lack of information about events that occurred during the first three eons compared to the current eon the Phanerozoic 6 74 The use of subseries subepochs has been ratified by the ICS 13 The content of the table is based on the official ICC produced and maintained by the ICS who also provide an online interactive version of this chart The interactive version is based on a service delivering a machine readable Resource Description Framework Web Ontology Language representation of the time scale which is available through the Commission for the Management and Application of Geoscience Information GeoSciML project as a service 75 and at a SPARQL end point 76 77 Eonothem Eon Erathem Era System Period Series Epoch Stage Age Major events Start million years ago note 7 Phanerozoic Cenozoic note 4 Quaternary Holocene Meghalayan 4 2 kiloyear event Austronesian expansion increasing industrial CO2 0 0042 Northgrippian 8 2 kiloyear event Holocene climatic optimum Sea level flooding of Doggerland and Sundaland Sahara becomes a desert End of Stone Age and start of recorded history Humans finally expand into the Arctic Archipelago and Greenland 0 0082 Greenlandian Climate stabilises Current interglacial and Holocene extinction begins Agriculture begins Humans spread across the wet Sahara and Arabia the Extreme North and the Americas mainland and the Caribbean 0 0117 0 000099 Pleistocene Upper Late Tarantian Eemian interglacial last glacial period ending with Younger Dryas Toba eruption Pleistocene megafauna including the last terror birds extinction Humans expand into Near Oceania and the Americas 0 129Chibanian Mid Pleistocene Transition occurs high amplitude 100 ka glacial cycles Rise of Homo sapiens 0 774 Calabrian Further cooling of the climate Giant terror birds go extinct Spread of Homo erectus across Afro Eurasia 1 8 Gelasian Start of Quaternary glaciations and unstable climate 78 Rise of the Pleistocene megafauna and Homo habilis 2 58 Neogene Pliocene Piacenzian Greenland ice sheet develops 79 as the cold slowly intensifies towards the Pleistocene Atmospheric O2 and CO2 content reaches present day levels while landmasses also reach their current locations e g the Isthmus of Panama joins the North and South Americas while allowing a faunal interchange The last non marsupial metatherians go extinct Australopithecus common in East Africa Stone Age begins 80 3 6 Zanclean Zanclean flooding of the Mediterranean Basin Cooling climate continues from the Miocene First equines and elephantines Ardipithecus in Africa 80 5 333 Miocene Messinian Messinian Event with hypersaline lakes in empty Mediterranean Basin Sahara desert formation begins Moderate icehouse climate punctuated by ice ages and re establishment of East Antarctic Ice Sheet Choristoderes the last non crocodilian crocodylomorphs and creodonts go extinct After separating from gorilla ancestors chimpanzee and human ancestors gradually separate Sahelanthropus and Orrorin in Africa 7 246 Tortonian 11 63 Serravallian Middle Miocene climate optimum temporarily provides a warm climate 81 Extinctions in middle Miocene disruption decreasing shark diversity First hippos Ancestor of great apes 13 82 Langhian 15 98 Burdigalian Orogeny in Northern Hemisphere Start of Kaikoura Orogeny forming Southern Alps in New Zealand Widespread forests slowly draw in massive amounts of CO2 gradually lowering the level of atmospheric CO2 from 650 ppmv down to around 100 ppmv during the Miocene 82 note 8 Modern bird and mammal families become recognizable The last of the primitive whales go extinct Grasses become ubiquitous Ancestor of apes including humans 83 84 Afro Arabia collides with Eurasia fully forming the Alpide Belt and closing the Tethys Ocean while allowing a faunal interchange At the same time Afro Arabia splits into Africa and West Asia 20 44Aquitanian 23 03 Paleogene Oligocene Chattian Grande Coupure extinction Start of widespread Antarctic glaciation 85 Rapid evolution and diversification of fauna especially mammals e g first macropods and seals Major evolution and dispersal of modern types of flowering plants Cimolestans miacoids and condylarths go extinct First neocetes modern fully aquatic whales appear 27 82 Rupelian 33 9 Eocene Priabonian Moderate cooling climate Archaic mammals e g creodonts miacoids condylarths etc flourish and continue to develop during the epoch Appearance of several modern mammal families Primitive whales and sea cows diversify after returning to water Birds continue to diversify First kelp diprotodonts bears and simians The multituberculates and leptictidans go extinct by the end of the epoch Reglaciation of Antarctica and formation of its ice cap End of Laramide and Sevier Orogenies of the Rocky Mountains in North America Hellenic Orogeny begins in Greece and Aegean Sea 37 71 Bartonian 41 2Lutetian 47 8 Ypresian Two transient events of global warming PETM and ETM 2 and warming climate until the Eocene Climatic Optimum The Azolla event decreased CO2 levels from 3500 ppm to 650 ppm setting the stage for a long period of cooling 82 note 8 Greater India collides with Eurasia and starts Himalayan Orogeny allowing a biotic interchange while Eurasia completely separates from North America creating the North Atlantic Ocean Maritime Southeast Asia diverges from the rest of Eurasia First passerines ruminants pangolins bats and true primates 56 Paleocene Thanetian Starts with Chicxulub impact and the K Pg extinction event wiping out all non avian dinosaurs and pterosaurs most marine reptiles many other vertebrates e g many Laurasian metatherians most cephalopods only Nautilidae and Coleoidea survived and many other invertebrates Climate tropical Mammals and birds avians diversify rapidly into a number of lineages following the extinction event while the marine revolution stops Multituberculates and the first rodents widespread First large birds e g ratites and terror birds and mammals up to bear or small hippo size Alpine orogeny in Europe and Asia begins First proboscideans and plesiadapiformes stem primates appear Some marsupials migrate to Australia 59 2 Selandian 61 6 Danian 66 Mesozoic Cretaceous Upper Late Maastrichtian Flowering plants proliferate after developing many features since the Carboniferous along with new types of insects while other seed plants gymnosperms and seed ferns decline More modern teleost fish begin to appear Ammonoids belemnites rudist bivalves sea urchins and sponges all common Many new types of dinosaurs e g tyrannosaurs titanosaurs hadrosaurs and ceratopsids evolve on land while crocodilians appear in water and probably cause the last temnospondyls to die out and mosasaurs and modern types of sharks appear in the sea The revolution started by marine reptiles and sharks reaches its peak though ichthyosaurs vanish few million years after being heavily reduced at the Bonarelli Event Toothed and toothless avian birds coexist with pterosaurs Modern monotremes metatherian including marsupials who migrate to South America and eutherian including placentals leptictidans and cimolestans mammals appear while the last non mammalian cynodonts die out First terrestrial crabs Many snails become terrestrial Further breakup of Gondwana creates South America Afro Arabia Antarctica Oceania Madagascar Greater India and the South Atlantic Indian and Antarctic Oceans and the islands of the Indian and some of the Atlantic Ocean Beginning of Laramide and Sevier Orogenies of the Rocky Mountains Atmospheric oxygen and carbon dioxide levels similar to present day Acritarchs disappear Climate initially warm but later it cools 72 1 0 2 Campanian 83 6 0 2 Santonian 86 3 0 5 Coniacian 89 8 0 3 Turonian 93 9 Cenomanian 100 5 Lower Early Albian 113 Aptian 121 4Barremian 125 77 Hauterivian 132 6 Valanginian 139 8Berriasian 145Jurassic Upper Late Tithonian Climate becomes humid again Gymnosperms especially conifers cycads and cycadeoids and ferns common Dinosaurs including sauropods carnosaurs stegosaurs and coelurosaurs become the dominant land vertebrates Mammals diversify into shuotheriids australosphenidans eutriconodonts multituberculates symmetrodonts dryolestids and boreosphenidans but mostly remain small First birds lizards snakes and turtles First brown algae rays shrimps crabs and lobsters Parvipelvian ichthyosaurs and plesiosaurs diverse Rhynchocephalians throughout the world Bivalves ammonoids and belemnites abundant Sea urchins very common along with crinoids starfish sponges and terebratulid and rhynchonellid brachiopods Breakup of Pangaea into Laurasia and Gondwana with the latter also breaking into two main parts the Pacific and Arctic Oceans form Tethys Ocean forms Nevadan orogeny in North America Rangitata and Cimmerian orogenies taper off Atmospheric CO2 levels 3 4 times the present day levels 1200 1500 ppmv compared to today s 400 ppmv 82 note 8 Crocodylomorphs last pseudosuchians seek out an aquatic lifestyle Mesozoic marine revolution continues from late Triassic Tentaculitans disappear 149 2 0 9Kimmeridgian 154 8 1 0 Oxfordian 161 5 1 0Middle Callovian 165 3 1 2Bathonian 168 2 1 3 Bajocian 170 9 1 4 Aalenian 174 7 1 0 Lower Early Toarcian 184 2 0 7 Pliensbachian 192 9 1 0 Sinemurian 199 5 0 3 Hettangian 201 4 0 2 Triassic Upper Late Rhaetian Archosaurs dominant on land as pseudosuchians and in the air as pterosaurs Dinosaurs also arise from bipedal archosaurs Ichthyosaurs and nothosaurs a group of sauropterygians dominate large marine fauna Cynodonts become smaller and nocturnal eventually becoming the first true mammals while other remaining synapsids die out Rhynchosaurs archosaur relatives also common Seed ferns called Dicroidium remained common in Gondwana before being replaced by advanced gymnosperms Many large aquatic temnospondyl amphibians Ceratitidan ammonoids extremely common Modern corals and teleost fish appear as do many modern insect orders and suborders First starfish Andean Orogeny in South America Cimmerian Orogeny in Asia Rangitata Orogeny begins in New Zealand Hunter Bowen Orogeny in Northern Australia Queensland and New South Wales ends c 260 225 Ma Carnian pluvial event occurs around 234 232 Ma allowing the first dinosaurs and lepidosaurs including rhynchocephalians to radiate Triassic Jurassic extinction event occurs 201 Ma wiping out all conodonts and the last parareptiles many marine reptiles e g all sauropterygians except plesiosaurs and all ichthyosaurs except parvipelvians all crocopodans except crocodylomorphs pterosaurs and dinosaurs and many ammonoids including the whole Ceratitida bivalves brachiopods corals and sponges First diatoms 86 208 5Norian 227Carnian 237 Middle Ladinian 242 Anisian 247 2Lower Early Olenekian 251 2Induan 251 902 0 024 Paleozoic Permian Lopingian Changhsingian Landmasses unite into supercontinent Pangaea creating the Urals Ouachitas and Appalachians among other mountain ranges the superocean Panthalassa or Proto Pacific also forms End of Permo Carboniferous glaciation Hot and dry climate A possible drop in oxygen levels Synapsids pelycosaurs and therapsids become widespread and dominant while parareptiles and temnospondyl amphibians remain common with the latter probably giving rise to modern amphibians in this period In the mid Permian lycophytes are heavily replaced by ferns and seed plants Beetles and flies evolve The very large arthropods and non tetrapod tetrapodomorphs go extinct Marine life flourishes in warm shallow reefs productid and spiriferid brachiopods bivalves forams ammonoids including goniatites and orthoceridans all abundant Crown reptiles arise from earlier diapsids and split into the ancestors of lepidosaurs kuehneosaurids choristoderes archosaurs testudinatans ichthyosaurs thalattosaurs and sauropterygians Cynodonts evolve from larger therapsids Olson s Extinction 273 Ma End Capitanian extinction 260 Ma and Permian Triassic extinction event 252 Ma occur one after another more than 80 of life on Earth becomes extinct in the lattermost including most retarian plankton corals Tabulata and Rugosa die out fully brachiopods bryozoans gastropods ammonoids the goniatites die off fully insects parareptiles synapsids amphibians and crinoids only articulates survived and all eurypterids trilobites graptolites hyoliths edrioasteroid crinozoans blastoids and acanthodians Ouachita and Innuitian orogenies in North America Uralian orogeny in Europe Asia tapers off Altaid orogeny in Asia Hunter Bowen Orogeny on Australian continent begins c 260 225 Ma forming the New England Fold Belt 254 14 0 07 Wuchiapingian 259 51 0 21 Guadalupian Capitanian 264 28 0 16 Wordian 266 9 0 4 Roadian 273 01 0 14 Cisuralian Kungurian 283 5 0 6Artinskian 290 1 0 26 Sakmarian 293 52 0 17 Asselian 298 9 0 15 Carboniferous note 9 Pennsylvanian note 10 Gzhelian Winged insects radiate suddenly some esp Protodonata and Palaeodictyoptera of them as well some millipedes and scorpions become very large First coal forests scale trees ferns club trees giant horsetails Cordaites etc Higher atmospheric oxygen levels Ice Age continues to the Early Permian Goniatites brachiopods bryozoa bivalves and corals plentiful in the seas and oceans First woodlice Testate forams proliferate Euramerica collides with Gondwana and Siberia Kazakhstania the latter of which forms Laurasia and the Uralian orogeny Variscan orogeny continues these collisions created orogenies and ultimately Pangaea Amphibians e g temnospondyls spread in Euramerica with some becoming the first amniotes Carboniferous Rainforest Collapse occurs initiating a dry climate which favors amniotes over amphibians Amniotes diversify rapidly into synapsids parareptiles cotylosaurs protorothyridids and diapsids Rhizodonts remained common before they died out by the end of the period First sharks 303 7Kasimovian 307 0 1Moscovian 315 2 0 2Bashkirian 323 2 Mississippian note 10 Serpukhovian Large lycopodian primitive trees flourish and amphibious eurypterids live amid coal forming coastal swamps radiating significantly one last time First gymnosperms First holometabolous paraneopteran polyneopteran odonatopteran and ephemeropteran insects and first barnacles First five digited tetrapods amphibians and land snails In the oceans bony and cartilaginous fishes are dominant and diverse echinoderms especially crinoids and blastoids abundant Corals bryozoans orthoceridans goniatites and brachiopods Productida Spiriferida etc recover and become very common again but trilobites and nautiloids decline Glaciation in East Gondwana continues from Late Devonian Tuhua Orogeny in New Zealand tapers off Some lobe finned fish called rhizodonts become abundant and dominant in freshwaters Siberia collides with a different small continent Kazakhstania 330 9 0 2Visean 346 7 0 4 Tournaisian 358 9 0 4 Devonian Upper Late Famennian First lycopods ferns seed plants seed ferns from earlier progymnosperms first trees the progymnosperm Archaeopteris and first winged insects palaeoptera and neoptera Strophomenid and atrypid brachiopods rugose and tabulate corals and crinoids are all abundant in the oceans First fully coiled cephalopods Ammonoidea and Nautilida independently with the former group very abundant especially goniatites Trilobites and ostracoderms decline while jawed fishes placoderms lobe finned and ray finned bony fish and acanthodians and early cartilaginous fish proliferate Some lobe finned fish transform into digited fishapods slowly becoming amphibious The last non trilobite artiopods die off First decapods like prawns and isopods Pressure from jawed fishes cause eurypterids to decline and some cephalopods to lose their shells while anomalocarids vanish Old Red Continent of Euramerica persists after forming in the Caledonian orogeny Beginning of Acadian Orogeny for Anti Atlas Mountains of North Africa and Appalachian Mountains of North America also the Antler Variscan and Tuhua orogenies in New Zealand A series of extinction events including the massive Kellwasser and Hangenberg ones wipe out many acritarchs corals sponges molluscs trilobites eurypterids graptolites brachiopods crinozoans e g all cystoids and fish including all placoderms and ostracoderms 372 2 1 6 Frasnian 382 7 1 6 Middle Givetian 387 7 0 8 Eifelian 393 3 1 2 Lower Early Emsian 407 6 2 6 Pragian 410 8 2 8 Lochkovian 419 2 3 2 Silurian Pridoli Ozone layer thickens First vascular plants and fully terrestrialised arthropods myriapods hexapods including insects and arachnids Eurypterids diversify rapidly becoming widespread and dominant Cephalopods continue to flourish True jawed fishes along with ostracoderms also roam the seas Tabulate and rugose corals brachiopods Pentamerida Rhynchonellida etc cystoids and crinoids all abundant Trilobites and molluscs diverse graptolites not as varied Three minor extinction events Some echinoderms go extinct Beginning of Caledonian Orogeny collision between Laurentia Baltica and one of the formerly small Gondwanan terranes for hills in England Ireland Wales Scotland and the Scandinavian Mountains Also continued into Devonian period as the Acadian Orogeny above thus Euramerica forms Taconic Orogeny tapers off Icehouse period ends late in this period after starting in Late Ordovician Lachlan Orogeny on Australian continent tapers off 423 2 3 Ludlow Ludfordian 425 6 0 9 Gorstian 427 4 0 5 Wenlock Homerian 430 5 0 7 Sheinwoodian 433 4 0 8 Llandovery Telychian 438 5 1 1 Aeronian 440 8 1 2 Rhuddanian 443 8 1 5 Ordovician Upper Late Hirnantian The Great Ordovician Biodiversification Event occurs as plankton increase in number invertebrates diversify into many new types especially brachiopods and molluscs e g long straight shelled cephalopods like the long lasting and diverse Orthocerida Early corals articulate brachiopods Orthida Strophomenida etc bivalves cephalopods nautiloids trilobites ostracods bryozoans many types of echinoderms blastoids cystoids crinoids sea urchins sea cucumbers and star like forms etc branched graptolites and other taxa all common Acritarchs still persist and common Cephalopods become dominant and common with some trending toward a coiled shell Anomalocarids decline Mysterious tentaculitans appear First eurypterids and ostracoderm fish appear the latter probably giving rise to the jawed fish at the end of the period First uncontroversial terrestrial fungi and fully terrestrialised plants Ice age at the end of this period as well as a series of mass extinction events killing off some cephalopods and many brachiopods bryozoans echinoderms graptolites trilobites bivalves corals and conodonts 445 2 1 4 Katian 453 0 7 Sandbian 458 4 0 9 Middle Darriwilian 467 3 1 1 Dapingian 470 1 4 Lower Early Floian formerly Arenig 477 7 1 4 Tremadocian 485 4 1 9 Cambrian Furongian Stage 10 Major diversification of fossils mainly show bilaterian life in the Cambrian Explosion as oxygen levels increase Numerous fossils most modern animal phyla including arthropods molluscs annelids echinoderms hemichordates and chordates appear Reef building archaeocyathan sponges initially abundant then vanish Stromatolites replace them but quickly fall prey to the Agronomic revolution when some animals started burrowing through the microbial mats affecting some other animals as well First artiopods including trilobites priapulid worms inarticulate brachiopods unhinged lampshells hyoliths bryozoans graptolites pentaradial echinoderms e g blastozoans crinozoans and eleutherozoans and numerous other animals Anomalocarids are dominant and giant predators while many Ediacaran fauna die out Crustaceans and molluscs diversify rapidly Prokaryotes protists e g forams algae and fungi continue to present day First vertebrates from earlier chordates Petermann Orogeny on the Australian continent tapers off 550 535 Ma Ross Orogeny in Antarctica Delamerian Orogeny c 514 490 Ma on Australian continent Some small terranes split off from Gondwana Atmospheric CO2 content roughly 15 times present day Holocene levels 6000 ppm compared to today s 400 ppm 82 note 8 Arthropods and streptophyta start colonising land 3 extinction events occur 517 502 amp 488 Ma the first and last of which wipe out many of the anomalocarids artiopods hyoliths brachiopods molluscs and conodonts early jawless vertebrates 489 5Jiangshanian 494 Paibian 497 Miaolingian Guzhangian 500 5 Drumian 504 5 Wuliuan 509Series 2 Stage 4 514Stage 3 521Terreneuvian Stage 2 529Fortunian 538 8 0 2 Proterozoic Neoproterozoic Ediacaran Good fossils of primitive animals Ediacaran biota flourish worldwide in seas possibly appearing after an explosion possibly caused by a large scale oxidation event 87 First vendozoans unknown affinity among animals cnidarians and bilaterians Enigmatic vendozoans include many soft jellied creatures shaped like bags disks or quilts like Dickinsonia Simple trace fossils of possible worm like Trichophycus etc Taconic Orogeny in North America Aravalli Range orogeny in Indian subcontinent Beginning of Pan African Orogeny leading to the formation of the short lived Ediacaran supercontinent Pannotia which by the end of the period breaks up into Laurentia Baltica Siberia and Gondwana Petermann Orogeny forms on Australian continent Beardmore Orogeny in Antarctica 633 620 Ma Ozone layer forms An increase in oceanic mineral levels 635 Cryogenian Possible Snowball Earth period Fossils still rare Late Ruker Nimrod Orogeny in Antarctica tapers off First uncontroversial animal fossils First hypothetical terrestrial fungi 88 and streptophyta 89 720Tonian Final assembly of Rodinia supercontinent occurs in early Tonian with breakup beginning c 800 Ma Sveconorwegian orogeny ends Grenville Orogeny tapers off in North America Lake Ruker Nimrod Orogeny in Antarctica 1 000 150 Ma Edmundian Orogeny c 920 850 Ma Gascoyne Complex Western Australia Deposition of Adelaide Superbasin and Centralian Superbasin begins on Australian continent First hypothetical animals from holozoans and terrestrial algal mats Many endosymbiotic events concerning red and green algae occur transferring plastids to ochrophyta e g diatoms brown algae dinoflagellates cryptophyta haptophyta and euglenids the events may have begun in the Mesoproterozoic 90 while the first retarians e g forams also appear eukaryotes diversify rapidly including algal eukaryovoric and biomineralised forms Trace fossils of simple multi celled eukaryotes 1000 note 11 Mesoproterozoic Stenian Narrow highly metamorphic belts due to orogeny as Rodinia forms surrounded by the Pan African Ocean Sveconorwegian orogeny starts Late Ruker Nimrod Orogeny in Antarctica possibly begins Musgrave Orogeny c 1 080 Musgrave Block Central Australia Stromatolites decline as algae proliferate 1200 note 11 Ectasian Platform covers continue to expand Algal colonies in the seas Grenville Orogeny in North America Columbia breaks up 1400 note 11 Calymmian Platform covers expand Barramundi Orogeny McArthur Basin Northern Australia and Isan Orogeny c 1 600 Ma Mount Isa Block Queensland First archaeplastidans the first eukaryotes with plastids from cyanobacteria e g red and green algae and opisthokonts giving rise to the first fungi and holozoans Acritarchs remains of marine algae possibly start appearing in the fossil record 1600 note 11 Paleoproterozoic Statherian First uncontroversial eukaryotes protists with nuclei and endomembrane system Columbia forms as the second undisputed earliest supercontinent Kimban Orogeny in Australian continent ends Yapungku Orogeny on Yilgarn craton in Western Australia Mangaroon Orogeny 1 680 1 620 Ma on the Gascoyne Complex in Western Australia Kararan Orogeny 1 650 Ma Gawler Craton South Australia Oxygen levels drop again 1800 note 11 Orosirian The atmosphere becomes much more oxygenic while more cyanobacterial stromatolites appear Vredefort and Sudbury Basin asteroid impacts Much orogeny Penokean and Trans Hudsonian Orogenies in North America Early Ruker Orogeny in Antarctica 2 000 1 700 Ma Glenburgh Orogeny Glenburgh Terrane Australian continent c 2 005 1 920 Ma Kimban Orogeny Gawler craton in Australian continent begins 2050 note 11 Rhyacian Bushveld Igneous Complex forms Huronian glaciation First hypothetical eukaryotes Multicellular Francevillian biota Kenorland disassembles 2300 note 11 Siderian Great Oxidation Event due to cyanobacteria increases oxygen Sleaford Orogeny on Australian continent Gawler Craton 2 440 2 420 Ma 2500 note 11 Archean Neoarchean Stabilization of most modern cratons possible mantle overturn event Insell Orogeny 2 650 150 Ma Abitibi greenstone belt in present day Ontario and Quebec begins to form stabilises by 2 600 Ma First uncontroversial supercontinent Kenorland and first terrestrial prokaryotes 2800 note 11 Mesoarchean First stromatolites probably colonial phototrophic bacteria like cyanobacteria Oldest macrofossils Humboldt Orogeny in Antarctica Blake River Megacaldera Complex begins to form in present day Ontario and Quebec ends by roughly 2 696 Ma 3200 note 11 Paleoarchean Prokaryotic archaea e g methanogens and bacteria e g cyanobacteria diversify rapidly along with early viruses First known phototrophic bacteria Oldest definitive microfossils First microbial mats Oldest cratons on Earth such as the Canadian Shield and the Pilbara Craton may have formed during this period note 12 Rayner Orogeny in Antarctica 3600 note 11 Eoarchean First uncontroversial living organisms at first protocells with RNA based genes around 4000 Ma after which true cells prokaryotes evolve along with proteins and DNA based genes around 3800 Ma The end of the Late Heavy Bombardment Napier Orogeny in Antarctica 4 000 200 Ma 4000 note 11 Hadean Formation of protolith of the oldest known rock Acasta Gneiss c 4 031 to 3 580 Ma 91 92 Possible first appearance of plate tectonics First hypothetical life forms End of the Early Bombardment Phase Oldest known mineral Zircon 4 404 8 Ma 93 Asteroids and comets bring water to Earth forming the first oceans Formation of Moon 4 510 Ma probably from a giant impact Formation of Earth 4 543 to 4 540 Ma 4567 3 0 16 note 11 Non Earth based geologic time scales EditMain articles Lunar geologic timescale Martian geologic timescale and Geology of VenusSome other planets and satellites in the Solar System have sufficiently rigid structures to have preserved records of their own histories for example Venus Mars and the Earth s Moon Dominantly fluid planets such as the gas giants do not comparably preserve their history Apart from the Late Heavy Bombardment events on other planets probably had little direct influence on the Earth and events on Earth had correspondingly little effect on those planets Construction of a time scale that links the planets is therefore of only limited relevance to the Earth s time scale except in a Solar System context The existence timing and terrestrial effects of the Late Heavy Bombardment are still a matter of debate note 13 Lunar selenological time scale Edit The geologic history of Earth s Moon has been divided into a time scale based on geomorphological markers namely impact cratering volcanism and erosion This process of dividing the Moon s history in this manner means that the time scale boundaries do not imply fundamental changes in geological processes unlike Earth s geologic time scale Five geologic systems periods Pre Nectarian Nectarian Imbrian Eratosthenian Copernican with the Imbrian divided into two series epochs Early and Late were defined in the latest Lunar geologic time scale 94 The Moon is unique in the Solar System in that it is the only other body from which we have rock samples with a known geological context Millions of years before present Martian geologic time scale Edit The geological history of Mars has been divided into two alternate time scales The first time scale for Mars was developed by studying the impact crater densities on the Martian surface Through this method four periods have been defined the Pre Noachian 4 500 4 100 Ma Noachian 4 100 3 700 Ma Hesperian 3 700 3 000 Ma and Amazonian 3 000 Ma to present 95 96 Martian time periods millions of years ago A second time scale based on mineral alteration observed by the OMEGA spectrometer on board the Mars Express Using this method three periods were defined the Phyllocian 4 500 4 000 Ma Theiikian 4 000 3 500 Ma and Siderikian 3 500 Ma to present 97 See also Edit nbsp Geology portalAge of the Earth Cosmic calendar Deep time Evolutionary history of life Formation and evolution of the Solar System Geological history of Earth Geology of Mars Geon geology Graphical timeline of the universe History of the Earth History of geology History of paleontology List of fossil sites List of geochronologic names Logarithmic timeline Lunar geologic timescale Martian geologic timescale Natural history New Zealand geologic time scale Prehistoric life Timeline of the Big Bang Timeline of evolution Timeline of the geologic history of the United States Timeline of human evolution Timeline of natural history Timeline of paleontologyNotes Edit It is now known that not all sedimentary layers are deposited purely horizontally but this principle is still a useful concept Time spans of geologic time units vary broadly and there is no numeric limitation on the time span they can represent They are limited by the time span of the higher rank unit they belong to and to the chronostratigraphic boundaries they are defined by a b c Precambrian or pre Cambrian is an informal geological term for time before the Cambrian period a b The Tertiary is a now obsolete geologic system period spanning from 66 Ma to 2 6 Ma It has no exact equivalent in the modern ICC but is approximately equivalent to the merged Palaeogene and Neogene systems periods a b Geochronometric date for the Ediacaran has been adjusted to reflect ICC v2022 10 as the formal definition for the base of the Cambrian has not changed Kratian time span is not given in the article It lies within the Neoarchean and prior to the Siderian The position shown here is an arbitrary division The dates and uncertainties quoted are according to the International Commission on Stratigraphy International Chronostratigraphic chart v2023 06 A indicates boundaries where a Global Boundary Stratotype Section and Point has been internationally agreed a b c d For more information on this see Atmosphere of Earth Evolution of Earth s atmosphere Carbon dioxide in the Earth s atmosphere and climate change Specific graphs of reconstructed CO2 levels over the past 550 65 and 5 million years can be seen at File Phanerozoic Carbon Dioxide png File 65 Myr Climate Change png File Five Myr Climate Change png respectively The Mississippian and Pennsylvanian are official sub systems sub periods a b This is divided into Lower Early Middle and Upper Late series epochs a b c d e f g h i j k l m Defined by absolute age Global Standard Stratigraphic Age The age of the oldest measurable craton or continental crust is dated to 3 600 3 800 Ma Not enough is known about extra solar planets for worthwhile speculation References Edit a b c Statues amp Guidelines International Commission on Stratigraphy Retrieved 5 April 2022 a b c d e f g h i Cohen K M Finney S C Gibbard P L Fan J X 1 September 2013 The ICS International Chronostratigraphic Chart Episodes updated ed 36 3 199 204 doi 10 18814 epiiugs 2013 v36i3 002 ISSN 0705 3797 S2CID 51819600 a b c d e f g h i j k l m Van Kranendonk Martin J Altermann Wladyslaw Beard Brian L Hoffman Paul F Johnson Clark M Kasting James F Melezhik Victor A Nutman Allen P 2012 A Chronostratigraphic Division of the Precambrian The Geologic Time Scale Elsevier pp 299 392 doi 10 1016 b978 0 444 59425 9 00016 0 ISBN 978 0 444 59425 9 retrieved 5 April 2022 International Commission on Stratigraphy International Geological Time Scale Retrieved 5 June 2022 a b c d Dalrymple G Brent 2001 The age of the Earth in the twentieth century a problem mostly solved Special Publications Geological Society of London 190 1 205 221 Bibcode 2001GSLSP 190 205D doi 10 1144 GSL SP 2001 190 01 14 S2CID 130092094 a b c d e Shields Graham A Strachan Robin A Porter Susannah M Halverson Galen P Macdonald Francis A Plumb Kenneth A de Alvarenga Carlos J Banerjee Dhiraj M Bekker Andrey Bleeker Wouter Brasier Alexander 2022 A template for an improved rock based subdivision of the pre Cryogenian timescale Journal of the Geological Society 179 1 jgs2020 222 Bibcode 2022JGSoc 179 222S doi 10 1144 jgs2020 222 ISSN 0016 7649 S2CID 236285974 a b c d e f g h i j k l Chapter 9 Chronostratigraphic Units stratigraphy org International Commission on Stratigraphy Retrieved 2 April 2022 a b c Chapter 3 Definitions and Procedures stratigraphy org International Commission on Stratigraphy Retrieved 2 April 2022 Global Boundary Stratotype Section and Points stratigraphy org International Commission on Stratigraphy Retrieved 2 April 2022 Knoll Andrew Walter Malcolm Narbonne Guy Christie Blick Nicholas 2006 The Ediacaran Period a new addition to the geologic time scale Lethaia 39 1 13 30 doi 10 1080 00241160500409223 Remane Jurgen Bassett Michael G Cowie John W Gohrbandt Klaus H Lane H Richard Michelsen Olaf Naiwen Wang the cooperation of members of ICS 1 September 1996 Revised guidelines for the establishment of global chronostratigraphic standards by the International Commission on Stratigraphy ICS Episodes 19 3 77 81 doi 10 18814 epiiugs 1996 v19i3 007 ISSN 0705 3797 a b c d e Michael Allaby 2020 A dictionary of geology and earth sciences Fifth ed Oxford ISBN 978 0 19 187490 1 OCLC 1137380460 a href Template Cite book html title Template Cite book cite book a CS1 maint location missing publisher link a b Aubry Marie Pierre Piller Werner E Gibbard Philip L Harper David A T Finney Stanley C 1 March 2022 Ratification of subseries subepochs as formal rank units in international chronostratigraphy Episodes 45 1 97 99 doi 10 18814 epiiugs 2021 021016 ISSN 0705 3797 S2CID 240772165 Desnoyers J 1829 Observations sur un ensemble de depots marins plus recents que les terrains tertiaires du bassin de la Seine et constituant une formation geologique distincte precedees d un apercu de la nonsimultaneite des bassins tertiares Observations on a set of marine deposits that are more recent than the tertiary terrains of the Seine basin and that constitute a distinct geological formation preceded by an outline of the non simultaneity of tertiary basins Annales des Sciences Naturelles in French 16 171 214 402 491 From p 193 Ce que je desirerais dont il faut egalement les distinguer What I would desire to prove above all is that the series of tertiary deposits continued and even began in the more recent basins for a long time perhaps after that of the Seine had been completely filled and that these later formations Quaternary 1 so to say should not retain the name of alluvial deposits any more than the true and ancient tertiary deposits from which they must also be distinguished However on the very same page Desnoyers abandoned the use of the term Quaternary because the distinction between Quaternary and Tertiary deposits wasn t clear From p 193 La crainte de voir mal comprise que ceux du bassin de la Seine The fear of seeing my opinion in this regard be misunderstood or exaggerated has made me abandon the word quaternary which at first I had wanted to apply to all deposits more recent than those of the Seine basin d Halloy d O J J 1822 Observations sur un essai de carte geologique de la France des Pays Bas et des contrees voisines Observations on a trial geological map of France the Low Countries and neighboring countries Annales des Mines 7 353 376 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint multiple names authors list link From page 373 La troisieme qui correspond a ce qu on a deja appele formation de la craie sera designe par le nom de terrain cretace The third which corresponds to what was already called the chalk formation will be designated by the name chalky terrain Humboldt Alexander von 1799 Ueber die unterirdischen Gasarten und die Mittel ihren Nachtheil zu vermindern ein Beytrag zur Physik der praktischen Bergbaukunde in German Vieweg Brongniart Alexandre 1770 1847 Auteur du texte 1829 Tableau des terrains qui composent l ecorce du globe ou Essai sur la structure de la partie connue de la terre Par Alexandre Brongniart in French Ogg J G Hinnov L A Huang C 2012 Jurassic The Geologic Time Scale Elsevier pp 731 791 doi 10 1016 b978 0 444 59425 9 00026 3 ISBN 978 0 444 59425 9 retrieved 1 May 2022 Murchison Murchison Sir Roderick Impey Verneuil Keyserling Graf Alexander 1842 On the Geological Structure of the Central and Southern Regions of Russia in Europe and of the Ural Mountains Print by R and J E Taylor Phillips John 1835 Illustrations of the Geology of Yorkshire Or A Description of the Strata and Organic Remains Accompanied by a Geological Map Sections and Plates of the Fossil Plants and Animals J Murray Sedgwick A Murchison R I 1 January 1840 XLIII On the Physical Structure of Devonshire and on the Subdivisions and Geological Relations of its older stratified Deposits amp c Transactions of the Geological Society of London s2 5 3 633 703 doi 10 1144 transgslb 5 3 633 ISSN 2042 5295 S2CID 128475487 Murchison Roderick Impey 1835 VII On the silurian system of rocks The London Edinburgh and Dublin Philosophical Magazine and Journal of Science 7 37 46 52 doi 10 1080 14786443508648654 ISSN 1941 5966 Lapworth Charles 1879 I On the Tripartite Classification of the Lower Palaeozoic Rocks Geological Magazine 6 1 1 15 Bibcode 1879GeoM 6 1L doi 10 1017 S0016756800156560 ISSN 0016 7568 S2CID 129165105 Bassett Michael G 1 June 1979 100 Years of Ordovician Geology Episodes 2 2 18 21 doi 10 18814 epiiugs 1979 v2i2 003 ISSN 0705 3797 Chisholm Hugh ed 1911 Cambria Encyclopaedia Britannica 11th ed Cambridge University Press Butcher Andy 26 May 2004 Re Ediacaran LISTSERV 16 0 AUSTRALIAN LINGUISTICS L Archives Archived from the original on 23 October 2007 Retrieved 19 July 2011 Place Details Ediacara Fossil Site Nilpena Parachilna SA Australia Department of Sustainability Environment Water Population and Communities Australian Heritage Database Commonwealth of Australia Archived from the original on 3 June 2011 Retrieved 19 July 2011 a b Holmes Arthur 9 June 1911 The association of lead with uranium in rock minerals and its application to the measurement of geological time Proceedings of the Royal Society of London Series A Containing Papers of a Mathematical and Physical Character 85 578 248 256 Bibcode 1911RSPSA 85 248H doi 10 1098 rspa 1911 0036 ISSN 0950 1207 a b c d e f g h i j k Fischer Alfred G Garrison Robert E 2009 The role of the Mediterranean region in the development of sedimentary geology a historical overview Sedimentology 56 1 3 41 Bibcode 2009Sedim 56 3F doi 10 1111 j 1365 3091 2008 01009 x S2CID 128604255 Sivin Nathan 1995 Science in ancient China researches and reflections Variorum ISBN 0 86078 492 4 OCLC 956775994 Adams Frank D 1938 The Birth and Development of the Geological Sciences Williams amp Wilkins ISBN 0 486 26372 X OCLC 165626104 Rudwick M J S 1985 The meaning of fossils episodes in the history of palaeontology Chicago University of Chicago Press ISBN 0 226 73103 0 OCLC 11574066 McCurdy Edward 1938 The notebooks of Leonardo da Vinci New York Reynal amp Hitchcock OCLC 2233803 Steno Nicolaus 1669 Nicolai Stenonis de solido intra solidvm natvraliter contento dissertationis prodromvs ad serenissimvm Ferdinandvm II in Latin W Junk Kardel Troels Maquet Paul 2018 2 27 the Prodromus to a Dissertation on a Solid Naturally Contained within a Solid Nicolaus Steno Berlin Heidelberg Springer Berlin Heidelberg pp 763 825 doi 10 1007 978 3 662 55047 2 38 ISBN 978 3 662 55046 5 retrieved 20 April 2022 Burnet Thomas 1681 Telluris Theoria Sacra orbis nostri originen et mutationes generales quasi am subiit aut olim subiturus est complectens Libri duo priores de Diluvio amp Paradiso in Latin London G Kettiby Werner Abraham Gottlob 1787 Kurze Klassifikation und Beschreibung der verschiedenen Gebirgsarten in German Dresden Walther Moro Anton Lazzaro 1740 De crostacei e degli altri marini corpi che si truovano su monti in Italian Appresso Stefano Monti Hutton James 1788 X Theory of the Earth or an Investigation of the Laws observable in the Composition Dissolution and Restoration of Land upon the Globe Transactions of the Royal Society of Edinburgh 1 2 209 304 doi 10 1017 S0080456800029227 ISSN 0080 4568 S2CID 251578886 Hutton James 1795 Theory of the Earth Vol 1 Edinburgh Hutton James 1795 Theory of the Earth Vol 2 Edinburgh Playfair John 1802 Illustrations of the Huttonian theory of the earth Digitised by London Natural History Museum Library Edinburgh Neill amp Co Lyell Sir Charles 1832 Principles of Geology Being an Attempt to Explain the Former Changes of the Earth s Surface by Reference to Causes Now in Operation Vol 1 London John Murray Lyell Sir Charles 1832 Principles of Geology Being an Attempt to Explain the Former Changes of the Earth s Surface by Reference to Causes Now in Operation Vol 2 London John Murray Lyell Sir Charles 1834 Principles of Geology Being an Inquiry how for the Former Changes of the Earth s Surface are Referrable to Causes Now in Operation Vol 3 London John Murray Holmes Arthur 1913 The age of the earth Gerstein University of Toronto London Harper a b Lewis Cherry L E 2001 Arthur Holmes vision of a geological timescale Geological Society London Special Publications 190 1 121 138 Bibcode 2001GSLSP 190 121L doi 10 1144 GSL SP 2001 190 01 10 ISSN 0305 8719 S2CID 128686640 Soddy Frederick 4 December 1913 Intra atomic Charge Nature 92 2301 399 400 Bibcode 1913Natur 92 399S doi 10 1038 092399c0 ISSN 0028 0836 S2CID 3965303 Holmes A 1 January 1959 A revised geological time scale Transactions of the Edinburgh Geological Society 17 3 183 216 doi 10 1144 transed 17 3 183 ISSN 0371 6260 S2CID 129166282 A Revised Geological Time Scale Nature 187 4731 27 28 1960 Bibcode 1960Natur 187T 27 doi 10 1038 187027d0 ISSN 0028 0836 S2CID 4179334 Harrison James M 1 March 1978 The Roots of IUGS Episodes 1 1 20 23 doi 10 18814 epiiugs 1978 v1i1 005 ISSN 0705 3797 International Union of Geological Sciences Commission on Stratigraphy 1986 Guidelines and statutes of the International Commission on Stratigraphy ICS J W Cowie Frankfurt a M Herausgegeben von der Senckenbergischen Naturforschenden Gesellschaft ISBN 3 924500 19 3 OCLC 14352783 W B Harland 1982 A geologic time scale Cambridge England Cambridge University Press ISBN 0 521 24728 4 OCLC 8387993 W B Harland 1990 A geologic time scale 1989 Cambridge Cambridge University Press ISBN 0 521 38361 7 OCLC 20930970 F M Gradstein James G Ogg A Gilbert Smith 2004 A geologic time scale 2004 Cambridge UK Cambridge University Press ISBN 0 511 08201 0 OCLC 60770922 Gradstein Felix M Ogg James G van Kranendonk Martin 23 July 2008 On the Geologic Time Scale 2008 Newsletters on Stratigraphy 43 1 5 13 doi 10 1127 0078 0421 2008 0043 0005 ISSN 0078 0421 a b c d e f g h i j k l m F M Gradstein 2012 The geologic time scale 2012 Volume 2 1st ed Amsterdam Elsevier ISBN 978 0 444 59448 8 OCLC 808340848 a b Ogg James G 2016 A concise geologic time scale 2016 Gabi Ogg F M Gradstein Amsterdam Netherlands Elsevier ISBN 978 0 444 59468 6 OCLC 949988705 a b F M Gradstein James G Ogg Mark D Schmitz Gabi Ogg 2020 Geologic time scale 2020 Amsterdam Netherlands ISBN 978 0 12 824361 9 OCLC 1224105111 a href Template Cite book html title Template Cite book cite book a CS1 maint location missing publisher link Crutzen Paul J Stoermer Eugene F 2021 Benner Susanne Lax Gregor Crutzen Paul J Poschl Ulrich eds The Anthropocene 2000 Paul J Crutzen and the Anthropocene A New Epoch in Earth s History The Anthropocene Politik Economics Society Science Cham Springer International Publishing vol 1 pp 19 21 doi 10 1007 978 3 030 82202 6 2 ISBN 978 3 030 82201 9 S2CID 245639062 retrieved 15 April 2022 Working Group on the Anthropocene Subcommission on Quaternary Stratigraphy Archived from the original on 7 April 2022 Retrieved 17 April 2022 Subramanian Meera 21 May 2019 Anthropocene now influential panel votes to recognise Earth s new epoch Nature d41586 019 01641 5 doi 10 1038 d41586 019 01641 5 ISSN 0028 0836 PMID 32433629 S2CID 182238145 Gibbard Philip L Bauer Andrew M Edgeworth Matthew Ruddiman William F Gill Jacquelyn L Merritts Dorothy J Finney Stanley C Edwards Lucy E Walker Michael J C Maslin Mark Ellis Erle C 15 November 2021 A practical solution the Anthropocene is a geological event not a formal epoch Episodes 45 4 349 357 doi 10 18814 epiiugs 2021 021029 ISSN 0705 3797 S2CID 244165877 Head Martin J Steffen Will Fagerlind David Waters Colin N Poirier Clement Syvitski Jaia Zalasiewicz Jan A Barnosky Anthony D Cearreta Alejandro Jeandel Catherine Leinfelder Reinhold 15 November 2021 The Great Acceleration is real and provides a quantitative basis for the proposed Anthropocene Series Epoch Episodes 45 4 359 376 doi 10 18814 epiiugs 2021 021031 ISSN 0705 3797 S2CID 244145710 Zalasiewicz Jan Waters Colin N Ellis Erle C Head Martin J Vidas Davor Steffen Will Thomas Julia Adeney Horn Eva Summerhayes Colin P Leinfelder Reinhold McNeill J R 2021 The Anthropocene Comparing Its Meaning in Geology Chronostratigraphy with Conceptual Approaches Arising in Other Disciplines Earth s Future 9 3 Bibcode 2021EaFut 901896Z doi 10 1029 2020EF001896 ISSN 2328 4277 S2CID 233816527 Bauer Andrew M Edgeworth Matthew Edwards Lucy E Ellis Erle C Gibbard Philip Merritts Dorothy J 16 September 2021 Anthropocene event or epoch Nature 597 7876 332 Bibcode 2021Natur 597 332B doi 10 1038 d41586 021 02448 z ISSN 0028 0836 PMID 34522014 S2CID 237515330 Bleeker W 17 March 2005 Gradstein Felix M Ogg James G Smith Alan G eds Toward a natural Precambrian time scale A Geologic Time Scale 2004 1 ed Cambridge University Press pp 141 146 doi 10 1017 cbo9780511536045 011 ISBN 978 0 521 78673 7 retrieved 9 April 2022 Strachan R Murphy J B Darling J Storey C Shields G 2020 Precambrian 4 56 1 Ga Geologic Time Scale 2020 Elsevier pp 481 493 doi 10 1016 b978 0 12 824360 2 00016 4 ISBN 978 0 12 824360 2 S2CID 229513433 retrieved 9 April 2022 Van Kranendonk Martin J 2012 16 A Chronostratigraphic Division of the Precambrian Possibilities and Challenges In Felix M Gradstein James G Ogg Mark D Schmitz abi M Ogg eds The geologic time scale 2012 1st ed Amsterdam Elsevier pp 359 365 doi 10 1016 B978 0 444 59425 9 00016 0 ISBN 978 0 44 459425 9 a b c Goldblatt C Zahnle K J Sleep N H Nisbet E G 2010 The Eons of Chaos and Hades Solid Earth 1 1 1 3 Bibcode 2010SolE 1 1G doi 10 5194 se 1 1 2010 Chambers John E July 2004 Planetary accretion in the inner Solar System PDF Earth and Planetary Science Letters 223 3 4 241 252 Bibcode 2004E amp PSL 223 241C doi 10 1016 j epsl 2004 04 031 Archived PDF from the original on 19 April 2012 El Albani Abderrazak Bengtson Stefan Canfield Donald E Riboulleau Armelle Rollion Bard Claire Macchiarelli Roberto et al 2014 The 2 1 Ga Old Francevillian Biota Biogenicity Taphonomy and Biodiversity PLOS ONE 9 6 e99438 Bibcode 2014PLoSO 999438E doi 10 1371 journal pone 0099438 PMC 4070892 PMID 24963687 El Albani Abderrazak Bengtson Stefan Canfield Donald E Bekker Andrey Macchiarelli Roberto Mazurier Arnaud Hammarlund Emma U et al 2010 Large colonial organisms with coordinated growth in oxygenated environments 2 1 Gyr ago PDF Nature 466 7302 100 104 Bibcode 2010Natur 466 100A doi 10 1038 nature09166 PMID 20596019 S2CID 4331375 permanent dead link Geological time scale Digital Atlas of Ancient Life Paleontological Research Institution Retrieved 17 January 2022 Geologic Timescale Elements in the International Chronostratigraphic Chart Retrieved 3 August 2014 Cox Simon J D SPARQL endpoint for CGI timescale service Archived from the original on 6 August 2014 Retrieved 3 August 2014 Cox Simon J D Richard Stephen M 2014 A geologic timescale ontology and service Earth Science Informatics 8 5 19 doi 10 1007 s12145 014 0170 6 S2CID 42345393 Hoag Colin Svenning Jens Christian 17 October 2017 African Environmental Change from the Pleistocene to the Anthropocene Annual Review of Environment and Resources 42 1 27 54 doi 10 1146 annurev environ 102016 060653 ISSN 1543 5938 Archived from the original on 1 May 2022 Retrieved 5 June 2022 Bartoli G Sarnthein M Weinelt M Erlenkeuser H Garbe Schonberg D Lea D W 2005 Final closure of Panama and the onset of northern hemisphere glaciation Earth and Planetary Science Letters 237 1 2 33 44 Bibcode 2005E amp PSL 237 33B doi 10 1016 j epsl 2005 06 020 a b Tyson Peter October 2009 NOVA Aliens from Earth Who s who in human evolution PBS Retrieved 8 October 2009 Gannon Colin 26 April 2013 Understanding the Middle Miocene Climatic Optimum Evaluation of Deuterium Values dD Related to Precipitation and Temperature Honors Projects in Science and Technology a b c d Royer Dana L 2006 CO2 forced climate thresholds during the Phanerozoic PDF Geochimica et Cosmochimica Acta 70 23 5665 75 Bibcode 2006GeCoA 70 5665R doi 10 1016 j gca 2005 11 031 Archived from the original PDF on 27 September 2019 Retrieved 6 August 2015 Here s What the Last Common Ancestor of Apes and Humans Looked Like Live Science 10 August 2017 Nengo Isaiah Tafforeau Paul Gilbert Christopher C Fleagle John G Miller Ellen R Feibel Craig Fox David L Feinberg Josh Pugh Kelsey D Berruyer Camille Mana Sara 2017 New infant cranium from the African Miocene sheds light on ape evolution Nature 548 7666 169 174 Bibcode 2017Natur 548 169N doi 10 1038 nature23456 ISSN 0028 0836 PMID 28796200 S2CID 4397839 Deconto Robert M Pollard David 2003 Rapid Cenozoic glaciation of Antarctica induced by declining atmospheric CO2 PDF Nature 421 6920 245 249 Bibcode 2003Natur 421 245D doi 10 1038 nature01290 PMID 12529638 S2CID 4326971 Medlin L K Kooistra W H C F Gersonde R Sims P A Wellbrock U 1997 Is the origin of the diatoms related to the end Permian mass extinction Nova Hedwigia 65 1 4 1 11 doi 10 1127 nova hedwigia 65 1997 1 hdl 10013 epic 12689 Williams Joshua J Mills Benjamin J W Lenton Timothy M 2019 A tectonically driven Ediacaran oxygenation event Nature Communications 10 1 2690 Bibcode 2019NatCo 10 2690W doi 10 1038 s41467 019 10286 x ISSN 2041 1723 PMC 6584537 PMID 31217418 Naranjo Ortiz Miguel A Gabaldon Toni 25 April 2019 Fungal evolution major ecological adaptations and evolutionary transitions Biological Reviews of the Cambridge Philosophical Society Cambridge Philosophical Society Wiley 94 4 1443 1476 doi 10 1111 brv 12510 ISSN 1464 7931 PMC 6850671 PMID 31021528 S2CID 131775942 Zarsky Jakub Zarsky Vojtech Hanacek Martin Zarsky Viktor 27 January 2022 Cryogenian Glacial Habitats as a Plant Terrestrialisation Cradle The Origin of the Anydrophytes and Zygnematophyceae Split Frontiers in Plant Science 12 735020 doi 10 3389 fpls 2021 735020 ISSN 1664 462X PMC 8829067 PMID 35154170 Yoon Hwan Su Hackett Jeremiah D Ciniglia Claudia Pinto Gabriele Bhattacharya Debashish 2004 A Molecular Timeline for the Origin of Photosynthetic Eukaryotes Molecular Biology and Evolution 21 5 809 818 doi 10 1093 molbev msh075 ISSN 1537 1719 PMID 14963099 Bowring Samuel A Williams Ian S 1999 Priscoan 4 00 4 03 Ga orthogneisses from northwestern Canada Contributions to Mineralogy and Petrology 134 1 3 Bibcode 1999CoMP 134 3B doi 10 1007 s004100050465 S2CID 128376754 Iizuka Tsuyoshi Komiya Tsuyoshi Maruyama Shigenori 2007 Chapter 3 1 The Early Archean Acasta Gneiss Complex Geological Geochronological and Isotopic Studies and Implications for Early Crustal Evolution Developments in Precambrian Geology Elsevier vol 15 pp 127 147 doi 10 1016 s0166 2635 07 15031 3 ISBN 978 0 444 52810 0 retrieved 1 May 2022 Wilde Simon A Valley John W Peck William H Graham Colin M 2001 Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4 4 Gyr ago Nature 409 6817 175 178 doi 10 1038 35051550 ISSN 0028 0836 PMID 11196637 S2CID 4319774 Wilhelms Don E 1987 The geologic history of the Moon Professional Paper United States Geological Survey doi 10 3133 pp1348 Tanaka Kenneth L 1986 The stratigraphy of Mars Journal of Geophysical Research 91 B13 E139 Bibcode 1986JGR 91E 139T doi 10 1029 JB091iB13p0E139 ISSN 0148 0227 Carr Michael H Head James W 1 June 2010 Geologic history of Mars Earth and Planetary Science Letters Mars Express after 6 Years in Orbit Mars Geology from Three Dimensional Mapping by the High Resolution Stereo Camera HRSC Experiment 294 3 185 203 Bibcode 2010E amp PSL 294 185C doi 10 1016 j epsl 2009 06 042 ISSN 0012 821X Bibring Jean Pierre Langevin Yves Mustard John F Poulet Francois Arvidson Raymond Gendrin Aline Gondet Brigitte Mangold Nicolas Pinet P Forget F Berthe Michel 21 April 2006 Global Mineralogical and Aqueous Mars History Derived from OMEGA Mars Express Data Science 312 5772 400 404 Bibcode 2006Sci 312 400B doi 10 1126 science 1122659 ISSN 0036 8075 PMID 16627738 S2CID 13968348 Further reading EditAubry Marie Pierre Van Couvering John A Christie Blick Nicholas Landing Ed Pratt Brian R Owen Donald E Ferrusquia Villafranca Ismael 2009 Terminology of geological time Establishment of a community standard Stratigraphy 6 2 100 105 doi 10 7916 D8DR35JQ Gradstein F M Ogg J G 2004 A Geologic Time scale 2004 Why How and Where Next PDF Lethaia 37 2 175 181 doi 10 1080 00241160410006483 Archived from the original PDF on 17 April 2018 Retrieved 30 November 2018 Gradstein Felix M Ogg James G Smith Alan G 2004 A Geologic Time Scale 2004 Cambridge UK Cambridge University Press ISBN 978 0 521 78142 8 Retrieved 18 November 2011 Gradstein Felix M Ogg James G Smith Alan G Bleeker Wouter Laurens Lucas J June 2004 A new Geologic Time Scale with special reference to Precambrian and Neogene Episodes 27 2 83 100 doi 10 18814 epiiugs 2004 v27i2 002 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint multiple names authors list link Ialenti Vincent 28 September 2014 Embracing Deep Time Thinking NPR NPR Cosmos amp Culture Ialenti Vincent 21 September 2014 Pondering Deep Time Could Inspire New Ways To View Climate Change NPR NPR Cosmos amp Culture Knoll Andrew H Walter Malcolm R Narbonne Guy M Christie Blick Nicholas 30 July 2004 A New Period for the Geologic Time Scale PDF Science 305 5684 621 622 doi 10 1126 science 1098803 PMID 15286353 S2CID 32763298 Archived PDF from the original on 15 December 2011 Retrieved 18 November 2011 Levin Harold L 2010 Time and Geology The Earth Through Time Hoboken New Jersey John Wiley amp Sons ISBN 978 0 470 38774 0 Retrieved 18 November 2011 Montenari Michael 2016 Stratigraphy and Timescales 1st ed Amsterdam Academic Press Elsevier ISBN 978 0 12 811549 7 Montenari Michael 2017 Advances in Sequence Stratigraphy 1st ed Amsterdam Academic Press Elsevier ISBN 978 0 12 813077 3 Montenari Michael 2018 Cyclostratigraphy and Astrochronology 1st ed Amsterdam Academic Press Elsevier ISBN 978 0 12 815098 6 Montenari Michael 2019 Case Studies in Isotope Stratigraphy 1st ed Amsterdam Academic Press Elsevier ISBN 978 0 12 817552 1 Montenari Michael 2020 Carbon Isotope Stratigraphy 1st ed Amsterdam Academic Press Elsevier ISBN 978 0 12 820991 2 Montenari Michael 2021 Calcareous Nannofossil Biostratigraphy 1st ed Amsterdam Academic Press Elsevier ISBN 978 0 12 824624 5 Nichols Gary 2013 Sedimentology and Stratigraphy 2nd ed Hoboken Wiley Blackwell ISBN 978 1 4051 3592 4 Williams Aiden 2019 Sedimentology and Stratigraphy 1st ed Forest Hills NY Callisto Reference ISBN 978 1 64116 075 9External links Edit nbsp Wikimedia Commons has media related to Geologic time scale nbsp The Wikibook Historical Geology has a page on the topic of Geological column The current version of the International Chronostratigraphic Chart can be found at stratigraphy org chart Interactive version of the International Chronostratigraphic Chart is found at stratigraphy org timescale A list of current Global Boundary Stratotype and Section Points is found at stratigraphy org gssps NASA Geologic Time archived 18 April 2005 GSA Geologic Time Scale archived 20 January 2019 British Geological Survey Geological Timechart GeoWhen Database archived 23 June 2004 National Museum of Natural History Geologic Time archived 11 November 2005 SeeGrid Geological Time Systems Archived 23 July 2008 at the Wayback Machine Information model for the geologic time scale Exploring Time from Planck Time to the lifespan of the universe Episodes Gradstein Felix M et al 2004 A new Geologic Time Scale with special reference to Precambrian and Neogene Episodes Vol 27 no 2 June 2004 pdf Lane Alfred C and Marble John Putman 1937 Report of the Committee on the measurement of geologic time Lessons for Children on Geologic Time archived 14 July 2011 Deep Time A History of the Earth Interactive Infographic Geology Buzz Geologic Time Scale Archived 12 August 2021 at the Wayback Machine Retrieved from https en wikipedia org w index php title Geologic time scale amp oldid 1180747618, wikipedia, wiki, book, books, library,

article

, read, download, free, free download, mp3, video, mp4, 3gp, jpg, jpeg, gif, png, picture, music, song, movie, book, game, games.