Geologic time scale

Last updated

The geologic time scale, proportionally represented as a log-spiral with some major events in Earth's history. A megaannus (Ma) represents one million (10 ) years. Geologic time scale - spiral - ICS colours (light) - path text.svg
The geologic time scale, proportionally represented as a log-spiral with some major events in Earth's history. A megaannus (Ma) represents one million (10 ) years.

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]

Contents

Principles

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). [3] 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. [4] [5]

Historically, regional geologic time scales were used [5] 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 International Chronostratigraphic Chart represents this ongoing effort.

Several key principles are used to determine the relative relationships of rocks and thus their chronostratigraphic position. [6] [7] [8] [9] [10] [11]

The law of superposition that states that in undeformed stratigraphic sequences the oldest strata will lie at the bottom of the sequence, while newer material stacks upon the surface. [6] [7] [9] [11] In practice, this means a younger rock will lie on top of an older rock unless there is evidence to suggest otherwise.

The principle of original horizontality that states layers of sediments will originally be deposited horizontally under the action of gravity. [6] [9] [11] However, it is now known that not all sedimentary layers are deposited purely horizontally, [11] [12] but this principle is still a useful concept.

The principle of lateral continuity that states layers of sediments extend laterally in all directions until either thinning out or being cut off by a different rock layer, i.e. they are laterally continuous. [6] Layers do not extend indefinitely; their limits are controlled by the amount and type of sediment in a sedimentary basin, and the geometry of that basin.

The principle of cross-cutting relationships that states a rock that cuts across another rock must be younger than the rock it cuts across. [6] [7] [9] [11]

The law of included fragments that states small fragments of one type of rock that are embedded in a second type of rock must have formed first, and were included when the second rock was forming. [9] [11]

The relationships of unconformities which are geologic features representing a gap in the geologic record. Unconformities are formed during periods of erosion or non-deposition, indicating non-continuous sediment deposition. [11] Observing the type and relationships of unconformities in strata allows geologist to understand the relative timing the strata.

The principle of faunal succession (where applicable) that states rock strata contain distinctive sets of fossils that succeed each other vertically in a specific and reliable order. [8] [11] This allows for a correlation of strata even when the horizon between them is not continuous.

Divisions of geologic time

The geologic time scale is divided into chronostratigraphic units and their corresponding geochronologic units.

Formal, hierarchical units of the geologic time scale (largest to smallest)
Chronostratigraphic unit (strata)Geochronologic unit (time)Time span [note 1]
EonothemEonSeveral hundred million years to two billion years
ErathemEraTens to hundreds of millions of years
SystemPeriodMillions of years to tens of millions of years
SeriesEpochHundreds of thousands of years to tens of millions of years
SubseriesSubepochThousands of years to millions of years
StageAgeThousands of years to millions of years

The subdivisions Early and Late 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 System (chronostratigraphic unit).

Rocks representing a given chronostratigraphic unit are that chronostratigraphic unit, and the time they were laid down in is the geochronologic unit, e.g., the rocks that represent the Silurian System are the Silurian System and they were deposited during the Silurian Period. This definition means the numeric age of a geochronologic unit can be changed (and is more often subject to change) when refined by geochronometry while the equivalent chronostratigraphic unit (the revision of which is less frequent) remains unchanged. 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 been changed; rather, the absolute age has merely been refined.

Terminology

Chronostratigraphy is the element of stratigraphy that deals with the relation between rock bodies and the relative measurement of geological time. [14] 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. Eonothem, erathem, system, series, subseries, stage, and substage are the hierarchical chronostratigraphic units. [14]

A geochronologic unit is a subdivision of geologic time. It is a numeric representation of an intangible property (time). [16] These units are arranged in a hierarchy: eon, era, period, epoch, subepoch, age, and subage. [14] 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). Geochronometry is the field of geochronology that numerically quantifies geologic time. [16]

A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed-upon reference point on a stratigraphic section that defines the lower boundaries of stages on the geologic time scale. [17] (Recently this has been used to define the base of a system) [18]

A Global Standard Stratigraphic Age (GSSA) [19] is a numeric-only, chronologic reference point used to define the base of geochronologic units prior to the Cryogenian. These points are arbitrarily defined. [14] 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 standard international units of the geologic time scale are published by the International Commission on Stratigraphy on the International Chronostratigraphic Chart; however, regional terms are still in use in some areas. The numeric values on the International Chronostratigrahpic Chart are represented by the unit Ma (megaannum, for 'million years'). For example, 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).

Naming of geologic time

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 suffix (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 International Commission on Stratigraphy 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. [14]

Informally, the time before the Cambrian is often referred to as the Precambrian or pre-Cambrian (Supereon). [4] [note 2]

Time span and etymology of geologic eonothem/eon names
NameTime spanDuration (million years)Etymology of name
Phanerozoic 538.8 to 0 million years ago538.8From Greek φανερός (phanerós) 'visible' or 'abundant' and ζωή (zoē) 'life'.
Proterozoic 2,500 to 538.8 million years ago1961.2From Greek πρότερος (próteros) 'former' or 'earlier' and ζωή (zoē) 'life'.
Archean 4,031 to 2,500 million years ago1531From Greek ἀρχή (archē) 'beginning, origin'.
Hadean 4,567.3 to 4,031 million years ago536.3From Hades, Ancient Greek : ᾍδης, romanized: Háidēs, the god of the underworld (hell, the inferno) in Greek mythology.
Time span and etymology of geologic erathem/era names
NameTime spanDuration (million years)Etymology of name
Cenozoic 66 to 0 million years ago66From Greek καινός (kainós) 'new' and ζωή (zōḗ) 'life'.
Mesozoic 251.9 to 66 million years ago185.902From Greek μέσο (méso) 'middle' and ζωή (zōḗ) 'life'.
Paleozoic 538.8 to 251.9 million years ago286.898From Greek παλιός (palaiós) 'old' and ζωή (zōḗ) 'life'.
Neoproterozoic 1,000 to 538.8 million years ago461.2From Greek νέος (néos) 'new' or 'young', πρότερος (próteros) 'former' or 'earlier', and ζωή (zōḗ) 'life'.
Mesoproterozoic 1,600 to 1,000 million years ago600From Greek μέσο (méso) 'middle', πρότερος (próteros) 'former' or 'earlier', and ζωή (zōḗ) 'life'.
Paleoproterozoic 2,500 to 1,600 million years ago900From Greek παλιός (palaiós) 'old', πρότερος (próteros) 'former' or 'earlier', and ζωή (zōḗ) 'life'.
Neoarchean 2,800 to 2,500 million years ago300From Greek νέος (néos) 'new' or 'young' and ἀρχαῖος (arkhaîos) 'ancient'.
Mesoarchean 3,200 to 2,800 million years ago400From Greek μέσο (méso) 'middle' and ἀρχαῖος (arkhaîos) 'ancient'.
Paleoarchean 3,600 to 3,200 million years ago400From Greek παλιός (palaiós) 'old' and ἀρχαῖος (arkhaîos) 'ancient'.
Eoarchean 4,031 to 3,600 million years ago431From Greek ἠώς (ēōs) 'dawn' and ἀρχαῖος (arkhaîos) 'ancient'.
Time span and etymology of geologic system/period names
NameTime spanDuration (million years)Etymology of name
Quaternary 2.6 to 0 million years ago2.58First introduced by Jules Desnoyers in 1829 for sediments in France's Seine Basin that appeared to be younger than Tertiary [note 3] rocks. [22]
Neogene 23 to 2.6 million years ago20.45Derived from Greek νέος (néos) 'new' and γενεά (geneá) 'genesis' or 'birth'.
Paleogene 66 to 23 million years ago42.97Derived from Greek παλιός (palaiós) 'old' and γενεά (geneá) 'genesis' or 'birth'.
Cretaceous ~ 145 to 66 million years ago~79Derived from Terrain Crétacé used in 1822 by Jean d'Omalius d'Halloy in reference to extensive beds of chalk within the Paris Basin. [23] Ultimately derived from Latin crēta 'chalk'.
Jurassic 201.4 to 145 million years ago~56.4Named after the Jura Mountains. Originally used by Alexander von Humboldt as 'Jura Kalkstein' (Jura limestone) in 1799. [24] Alexandre Brongniart was the first to publish the term Jurassic in 1829. [25] [26]
Triassic 251.9 to 201.4 million years ago50.502From 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 ago46.998Named after the historical region of Perm, Russian Empire. [27]
Carboniferous 358.9 to 298.9 million years ago60Means 'coal-bearing', from the Latin carbō (coal) and ferō (to bear, carry). [28]
Devonian 419.2 to 358.9 million years ago60.3Named after Devon, England. [29]
Silurian 443.8 to 419.2 million years ago24.6Named after the Celtic tribe, the Silures. [30]
Ordovician 485.4 to 443.8 million years ago41.6Named after the Celtic tribe, Ordovices. [31] [32]
Cambrian 538.8 to 485.4 million years ago53.4Named for Cambria, a latinised form of the Welsh name for Wales, Cymru. [33]
Ediacaran 635 to 538.8 million years ago~96.2Named for the Ediacara Hills. Ediacara is possibly a corruption of Kuyani 'Yata Takarra' 'hard or stony ground'. [34] [35]
Cryogenian 720 to 635 million years ago~85From Greek κρύος (krýos) 'cold' and γένεσις (génesis) 'birth'. [5]
Tonian 1,000 to 720 million years ago~280From Greek τόνος (tónos) 'stretch'. [5]
Stenian 1,200 to 1,000 million years ago200From Greek στενός (stenós) 'narrow'. [5]
Ectasian 1,400 to 1,200 million years ago200From Greek ἔκτᾰσῐς (éktasis) 'extension'. [5]
Calymmian 1,600 to 1,400 million years ago200From Greek κάλυμμᾰ (kálumma) 'cover'. [5]
Statherian 1,800 to 1,600 million years ago200From Greek σταθερός (statherós) 'stable'. [5]
Orosirian 2,050 to 1,800 million years ago250From Greek ὀροσειρά (oroseirá) 'mountain range'. [5]
Rhyacian 2,300 to 2,050 million years ago250From Greek ῥύαξ (rhýax) 'stream of lava'. [5]
Siderian 2,500 to 2,300 million years ago200From Greek σίδηρος (sídēros) 'iron'. [5]
Time span and etymology of geologic series/epoch names
NameTime spanDuration (million years)Etymology of name
Holocene 0.012 to 0 million years ago0.0117From Greek ὅλος (hólos) 'whole' and καινός (kainós) 'new'
Pleistocene 2.58 to 0.012 million years ago2.5683Coined in the early 1830s from Greek πλεῖστος (pleîstos) 'most' and καινός (kainós) 'new'
Pliocene 5.33 to 2.58 million years ago2.753Coined in the early 1830s from Greek πλείων (pleíōn) 'more' and καινός (kainós) 'new'
Miocene 23.03 to 5.33 million years ago17.697Coined in the early 1830s from Greek μείων (meíōn) 'less' and καινός (kainós) 'new'
Oligocene 33.9 to 23.03 million years ago10.87Coined in the 1850s from Greek ὀλίγος (olígos) 'few' and καινός (kainós) 'new'
Eocene 56 to 33.9 million years ago22.1Coined in the early 1830s from Greek ἠώς (ēōs) 'dawn' and καινός (kainós) 'new', referring to the dawn of modern life during this epoch
Paleocene 66 to 56 million years ago10Coined by Wilhelm Philippe Schimper in 1874 as a portmanteau of paleo- + Eocene, but on the surface from Greek παλαιός (palaios) 'old' and καινός (kainós) 'new'
Upper Cretaceous 100.5 to 66 million years ago34.5See Cretaceous
Lower Cretaceous 145 to 100.5 million years ago44.5
Upper Jurassic
161.5 to 145 million years ago16.5See Jurassic
Middle Jurassic 174.7 to 161.5 million years ago13.2
Lower Jurassic
201.4 to 174.7 million years ago26.7
Upper Triassic 237 to 201.4 million years ago35.6See Triassic
Middle Triassic
247.2 to 237 million years ago10.2
Lower Triassic 251.9 to 247.2 million years ago4.702
Lopingian 259.51 to 251.9 million years ago7.608Named for Loping, China, an anglicization of Mandarin 乐平 (lèpíng) 'peaceful music'
Guadalupian 273.01 to 259.51 million years ago13.5Named for the Guadalupe Mountains of the American Southwest, ultimately from Arabic وَادِي ٱل (wādī al) 'valley of the' and Latin lupus 'wolf' via Spanish
Cisuralian 298.9 to 273.01 million years ago25.89From Latin cis- (before) + Russian Урал (Ural), referring to the western slopes of the Ural Mountains
Upper Pennsylvanian 307 to 298.9 million years ago8.1Named for the US state of Pennsylvania, from William Penn + Latin silvanus (forest) + -ia by analogy to Transylvania
Middle Pennsylvanian 315.2 to 307 million years ago8.2
Lower Pennsylvanian 323.2 to 315.2 million years ago8
Upper Mississippian 330.9 to 323.2 million years ago7.7Named for the Mississippi River, from Ojibwe ᒥᐦᓯᓰᐱ (misi-ziibi) 'great river'
Middle Mississippian 346.7 to 330.9 million years ago15.8
Lower Mississippian 358.9 to 346.7 million years ago12.2
Upper Devonian 382.7 to 358.9 million years ago23.8See Devonian
Middle Devonian 393.3 to 382.7 million years ago10.6
Lower Devonian 419.2 to 393.3 million years ago25.9
Pridoli 423 to 419.2 million years ago3.8Named for the Homolka a Přídolí nature reserve near Prague, Czechia
Ludlow 427.4 to 423 million years ago4.4Named after Ludlow, England
Wenlock 433.4 to 427.4 million years ago6Named for the Wenlock Edge in Shropshire, England
Llandovery 443.8 to 433.4 million years ago10.4Named after Llandovery, Wales
Upper Ordovician 458.4 to 443.8 million years ago14.6See Ordovician
Middle Ordovician 470 to 458.4 million years ago11.6
Lower Ordovician 485.4 to 470 million years ago15.4
Furongian 497 to 485.4 million years ago11.6From Mandarin 芙蓉 (fúróng) 'lotus', referring to the state symbol of Hunan
Miaolingian 509 to 497 million years ago12Named for the Miao Ling  [ zh ] mountains of Guizhou, Mandarin for 'sprouting peaks'
Cambrian Series 2 (informal) 521 to 509 million years ago12See Cambrian
Terreneuvian 538.8 to 521 million years ago17.8Named for Terre-Neuve, a French calque of Newfoundland

History of the geologic time scale

Early history

While a modern geological time scale was not formulated until 1911 [36] 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. [37] This view was shared by a few of Xenophanes's 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 [38] (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. [37] 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. [37] Avicenna also recognised fossils as "petrifications of the bodies of plants and animals", [39] with the 13th-century Dominican bishop Albertus Magnus (c. 1200–1280) extending this into a theory of a petrifying fluid. [40] [ 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. [37] 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': [41] [37]

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. [37]

Establishment of primary principles

Niels Stensen, more commonly known as Nicolas Steno (1638–1686), is credited with establishing four of the guiding principles of stratigraphy. [37] In De solido intra solidum naturaliter contento dissertationis prodromus Steno states: [6] [42]

  • 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. [37] 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:

Formulation of a modern geologic time scale

The apparent, earliest formal division of the geologic record with respect to time was introduced during the era of Biblical models 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". [43] [37] Anton Moro (1687–1784) also used primary and secondary divisions for rock units but his mechanism was volcanic. [44] [37] 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. [37] 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. [45] [7] [46] Hutton's theory would later become known as uniformitarianism, popularised by John Playfair [47] (1748–1819) and later Charles Lyell (1797–1875) in his Principles of Geology . [9] [48] [49] 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

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. [3] 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. [3] 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. [36] [50] [51] The discovery of isotopes in 1913 [52] 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. [3] [51] [53] [54]

Modern international geologic time scale

The establishment of the IUGS in 1961 [55] and acceptance of the Commission on Stratigraphy (applied in 1965) [56] 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, [57] 1989, [58] 2004, [59] 2008, [60] 2012, [61] 2016, [62] and 2020. [63] 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 [62] and 2020 [63] ) 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.

SiderianRhyacianOrosirianStatherianCalymmianEctasianStenianTonianCryogenianEdiacaranCambrianOrdovicianDevonianCarboniferousPermianTriassicJurassicCretaceousPaleogeneEoarcheanPaleoarcheanMesoarcheanNeoarcheanPaleoproterozoicMesoproterozoicNeoproterozoicPaleozoicMesozoicCenozoicHadeanArcheanProterozoicPhanerozoicPrecambrianGeologic time scale
CambrianOrdovicianSilurianDevonianCarboniferousPermianTriassicJurassicCretaceousPaleogeneNeogeneQuaternaryPaleozoicMesozoicCenozoicPhanerozoicGeologic time scale
PaleoceneEoceneOligoceneMiocenePliocenePleistoceneHolocenePaleogeneNeogeneQuaternaryCenozoicGeologic time scale
GelasianCalabrian (stage)ChibanianLate PleistocenePleistoceneHoloceneQuaternaryGeologic time scale

Horizontal scale is Millions of years (above timelines) / Thousands of years (below timeline)

GreenlandianNorthgrippianMeghalayanHoloceneGeologic time scale

Major proposed revisions to the ICC

Proposed Anthropocene Series/Epoch

First suggested in 2000, [64] 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. [65] 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. [66] Nevertheless, the definition of the Anthropocene as a geologic time period rather than a geologic event remains controversial and difficult. [67] [68] [69] [70]

Proposals for revisions to pre-Cryogenian timeline

Shields et al. 2021

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. [4] This work assessed the geologic history of the currently defined eons and eras of the pre-Cambrian, [note 2] and the proposals in the "Geological Time Scale" books 2004, [71] 2012, [5] and 2020. [72] Their recommend revisions [4] of the pre-Cryogenian geologic time scale were (changes from the current scale [v2023/09] 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 κράτος (krátos) '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 Greek σκουριά (skouriá) '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 4]
      • Kleisian or Syndian (1000–800 Ma) – respectively from Greek κλείσιμο (kleísimo) 'closure' and σύνδεση (sýndesi) '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 5]

Geologic time scale

Current ICC pre-Cambrian timeline (v2023/09), shown to scale:

Geologic time scale

Van Kranendonk et al. 2012 (GTS2012)

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. [73] As of April 2022 these proposed changes have not been accepted by the ICS. The proposed changes (changes from the current scale [v2023/09]) 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 Kaapvaal (Southern Africa) and Pilbara (Western Australia) cratons, to reflect the growth of stable continental nuclei or proto-cratonic kernels. [61]
      • 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. [61]
    • Neoarchean Era/Erathem (2780–2420 Ma)
  • Proterozoic Eon/Eonothem (2420–538.8 Ma) [note 4]
    • Paleoproterozoic Era/Erathem (2420–1780 Ma)
      • Oxygenian Period/System (2420–2250 Ma) – named for displaying the first evidence for a global oxidising atmosphere. [61]
      • 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) [76] [77] first fossil appearance of eukaryotes. [61]
      • Columbian Period/System (2060–1780 Ma) – named after the supercontinent Columbia. [61]
    • Mesoproterozoic Era/Erathem (1780–850 Ma)
      • Rodinian Period/System (1780–850 Ma) – named after the supercontinent Rodinia, stable environment. [61]

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

Geologic time scale

Current ICC pre-Cambrian timeline (v2023/09), shown to scale:

Geologic time scale

Table of geologic time

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 2] 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). [4] [78] The use of subseries/subepochs has been ratified by the ICS. [15]

While some regional terms are still in use, [5] the table of geologic time conforms to the nomenclature, ages, and colour codes set forth by the International Commission on Stratigraphy in the official International Chronostratigraphic Chart. [1] [79] The International Commission on Stratigraphy 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 [80] and at a SPARQL end-point. [81] [82]

Non-Earth based geologic time scales

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 giant planets, 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 12]

Lunar (selenological) time scale

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. [100] The Moon is unique in the Solar System in that it is the only other body from which humans have rock samples with a known geological context.

Early ImbrianLate ImbrianPre-NectarianNectarianEratosthenianCopernican periodGeologic time scale
Millions of years before present

Martian geologic time scale

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). [101] [102]

Pre-NoachianNoachianHesperianAmazonian (Mars)Geologic time scale
Martian time periods (millions of years ago)

Epochs:

Geologic time scale

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). [103]

Geologic time scale

See also

Notes

  1. ↑ 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.
  2. 1 2 3 Precambrian or pre-Cambrian is an informal geological term for time before the Cambrian period
  3. 1 2 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. [20] [21]
  4. 1 2 Geochronometric date for the Ediacaran has been adjusted to reflect ICC v2023/09 as the formal definition for the base of the Cambrian has not changed.
  5. ↑ 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.
  6. ↑ The dates and uncertainties quoted are according to the International Commission on Stratigraphy International Chronostratigraphic chart (v2023/06). An * indicates boundaries where a Global Boundary Stratotype Section and Point has been internationally agreed.
  7. 1 2 3 4 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.
  8. ↑ The Mississippian and Pennsylvanian are official sub-systems/sub-periods.
  9. 1 2 This is divided into Lower/Early, Middle, and Upper/Late series/epochs
  10. 1 2 3 4 5 6 7 8 9 10 11 12 13 Defined by absolute age (Global Standard Stratigraphic Age).
  11. ↑ The age of the oldest measurable craton, or continental crust, is dated to 3,600–3,800 Ma.
  12. ↑ Not enough is known about extra-solar planets for worthwhile speculation.

Related Research Articles

<span class="mw-page-title-main">Neoproterozoic</span> Third and last era of the Proterozoic Eon

The Neoproterozoic Era is the last of the three geologic eras of the Proterozoic eon, spanning from 1 billion to 538.8 million years ago, and is the last era of the Precambrian "supereon". It is preceded by the Mesoproterozoic era and succeeded by the Paleozoic era of the Phanerozoic eon, and is further subdivided into three periods, the Tonian, Cryogenian and Ediacaran.

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

<span class="mw-page-title-main">Quaternary</span> Third and current period of the Cenozoic Era, from 2.58 million years ago to the present

The Quaternary is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the Phanerozoic eon. It follows the Neogene Period and spans from 2.58 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene and the Holocene ; a proposed third epoch, the Anthropocene, was rejected in 2024 by IUGS, the governing body of the ICS.

Tertiary is an obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the extinction of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start of the Cenozoic Era, and extended to the beginning of the Quaternary glaciation at the end of the Pliocene Epoch. The time span covered by the Tertiary has no exact equivalent in the current geologic time system, but it is essentially the merged Paleogene and Neogene periods, which are informally called the Early Tertiary and the Late Tertiary, respectively. Even though the term Tertiary has been declared obsolete, some high school curriculums still teach the geologic periods as Precambrian, Paleozoic, Mesozoic, (Cenozoic-)Tertiary and (Cenozoic-)Quaternary.

<span class="mw-page-title-main">Barremian</span> Fourth age and stage of the Early/Lower Cretaceous

The Barremian is an age in the geologic timescale between 125.77 Ma and 121.4 ± 1.0 Ma It is a subdivision of the Early Cretaceous Epoch. It is preceded by the Hauterivian and followed by the Aptian Stage.

The International Commission on Stratigraphy (ICS), sometimes unofficially referred to as the "International Stratigraphic Commission", is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigraphical, geological, and geochronological matters on a global scale.

<span class="mw-page-title-main">Cisuralian</span> First series of the Permian

The Cisuralian is the first series/epoch of the Permian. The Cisuralian was preceded by the Pennsylvanian and followed by the Guadalupian. The Cisuralian Epoch is named after the western slopes of the Ural Mountains in Russia and Kazakhstan and dates between 298.9 ± 0.15 – 272.3 ± 0.5 Ma.

The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya and 83.6 ± 0.7 mya. The Santonian is preceded by the Coniacian and is followed by the Campanian.

In the geologic timescale, the Kimmeridgian is an age in the Late Jurassic Epoch and a stage in the Upper Jurassic Series. It spans the time between 154.8 ±0.8 Ma and 149.2 ±0.7 Ma. The Kimmeridgian follows the Oxfordian and precedes the Tithonian.

In the geologic timescale, the Sakmarian is an age or stage of the Permian period. It is a subdivision of the Cisuralian Epoch or Series. The Sakmarian lasted between 293.52 and 290.1 million years ago (Ma). It was preceded by the Asselian and followed by the Artinskian.

Chronostratigraphy is the branch of stratigraphy that studies the ages of rock strata in relation to time.

<span class="mw-page-title-main">Homerian</span> Fifth stage of the Silurian

In the geologic timescale, the Homerian is an age of the Wenlock Epoch of the Silurian Period of the Paleozoic Era of the Phanerozoic Eon that is comprehended between 430.5 ± 0.7 Ma and 427.4 ± 0.5 Ma, approximately. The Homerian Age succeeds the Sheinwoodian Age and precedes the Gorstian Age.

<span class="mw-page-title-main">Sheinwoodian</span>

In the geologic timescale, the Sheinwoodian is the age of the Wenlock Epoch of the Silurian Period of the Paleozoic Era of the Phanerozoic Eon that is comprehended between 433.4 ± 0.8 Ma and 430.5 ± 0.7 Ma, approximately. The Sheinwoodian Age succeeds the Telychian Age and precedes the Homerian Age.

In stratigraphy, paleontology, geology, and geobiology, an erathem is the total stratigraphic unit deposited during a certain corresponding span of time during an era in the geologic timescale.

<span class="mw-page-title-main">Group (stratigraphy)</span> A group of geologic formations

In geology, a group is a lithostratigraphic unit consisting of a series of related formations that have been classified together to form a group. Formations are the fundamental unit of stratigraphy. Groups may sometimes be combined into supergroups.

The Namurian is a stage in the regional stratigraphy of northwest Europe, with an age between roughly 331 and 319 Ma. It is a subdivision of the Carboniferous system or period, as well as the regional Silesian series. The Namurian is named for the Belgian city and province of Namur where strata of this age occur. The Millstone Grit Group in the lithostratigraphy of northern England and parts of Wales is also of Namurian age.

The Stephanian is a stage in the regional stratigraphy of northwest Europe with an age between roughly 307.5 and 299 Ma. It is a subdivision of the Carboniferous system or period and the regional Silesian series. The uppermost units of the Coal Measures of England and Wales are probably of Stephanian age, though the larger part of this formation is referred to the earlier Westphalian. The stage derives its name from the city of Saint-Étienne for its coal mining basin in eastern central France where strata of this age occur.

The Anthropocene Working Group (AWG) is an interdisciplinary research group dedicated to the study of the Anthropocene as a geological time unit. It was established in 2009 as part of the Subcommission on Quaternary Stratigraphy (SQS), a constituent body of the International Commission on Stratigraphy (ICS). As of 2021, the research group features 37 members, with the physical geographer Simon Turner as Secretary and the geologist Colin Neil Waters as chair of the group. The late Nobel Prize-winning Paul Crutzen, who popularized the word 'Anthropocene' in 2000, had also been a member of the group until he died on January 28, 2021. The main goal of the AWG is providing scientific evidence robust enough for the Anthropocene to be formally ratified by the International Union of Geological Sciences (IUGS) as an epoch within the Geologic time scale.

<span class="mw-page-title-main">Geological event</span> Occurrence in Earths history recorded in geological strata

A geological event is a temporary and spatially heterogeneous and dynamic (diachronous) happening in Earth history that contributes to the transformation of Earth system and the formation of geological strata. Event stratigraphy was first proposed as a system for the recognition, study and correlation of the effects of important physical or biological events on the broader stratigraphical record.

References

  1. 1 2 3 "Statues & Guidelines". International Commission on Stratigraphy. Retrieved 5 April 2022.
  2. 1 2 3 4 5 6 7 8 9 Cohen, K.M.; Finney, S.C.; Gibbard, P.L.; Fan, J.-X. (1 September 2013). "The ICS International Chronostratigraphic Chart". Episodes. 36 (3) (updated ed.): 199–204. doi: 10.18814/epiiugs/2013/v36i3/002 . ISSN   0705-3797. S2CID   51819600.
  3. 1 2 3 4 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.
  4. 1 2 3 4 5 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.
  5. 1 2 3 4 5 6 7 8 9 10 11 12 13 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
  6. 1 2 3 4 5 6 Steno, Nicolaus (1669). Nicolai Stenonis de solido intra solidvm natvraliter contento dissertationis prodromvs ad serenissimvm Ferdinandvm II ... (in Latin). W. Junk.
  7. 1 2 3 4 Hutton, James (1795). Theory of the Earth. Vol. 1. Edinburgh.
  8. 1 2 Smith, William (1 June 1816). Strata identified by organized fossils, containing prints on colored paper of the most characteristic specimens in each stratum. London: W. Arding. doi:10.5962/bhl.title.106808.
  9. 1 2 3 4 5 6 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.
  10. ↑ "International Commission on Stratigraphy - Stratigraphic Guide - Chapter 9. Chronostratigraphic Units". stratigraphy.org. Retrieved 16 April 2024.
  11. 1 2 3 4 5 6 7 8 Boggs, Sam (2011). Principles of sedimentology and stratigraphy (5th ed.). Boston, Munich: Prentice Hall. ISBN   978-0-321-74576-7.
  12. ↑ Mehta, A; Barker, G C (1 April 1994). "The dynamics of sand". Reports on Progress in Physics. 57 (4): 383–416. doi:10.1088/0034-4885/57/4/002. ISSN   0034-4885.
  13. 1 2 3 4 5 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)
  14. 1 2 3 4 5 6 7 8 9 10 11 "Chapter 9. Chronostratigraphic Units". stratigraphy.org. International Commission on Stratigraphy. Retrieved 2 April 2022.
  15. 1 2 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.
  16. 1 2 "Chapter 3. Definitions and Procedures". stratigraphy.org. International Commission on Stratigraphy. Retrieved 2 April 2022.
  17. ↑ "Global Boundary Stratotype Section and Points". stratigraphy.org. International Commission on Stratigraphy. Retrieved 2 April 2022.
  18. ↑ 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. Bibcode:2006Letha..39...13K. doi:10.1080/00241160500409223.
  19. ↑ 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.
  20. ↑ Head, Martin J.; Gibbard, Philip; Salvador, Amos (1 June 2008). "The Quaternary: its character and definition". Episodes. 31 (2): 234–238. doi:10.18814/epiiugs/2008/v31i2/009. ISSN   0705-3797.
  21. ↑ Gibbard, Philip L.; Head, Martin J.; Walker, Michael J. C.; the Subcommission on Quaternary Stratigraphy (20 January 2010). "Formal ratification of the Quaternary System/Period and the Pleistocene Series/Epoch with a base at 2.58 Ma". Journal of Quaternary Science. 25 (2): 96–102. Bibcode:2010JQS....25...96G. doi:10.1002/jqs.1338. ISSN   0267-8179.
  22. ↑ 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.)
  23. ↑ 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".)
  24. ↑ 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.
  25. ↑ 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).{{cite book}}: CS1 maint: numeric names: authors list (link)
  26. ↑ 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
  27. ↑ 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.
  28. ↑ 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.
  29. ↑ 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.
  30. ↑ 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.
  31. ↑ 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.
  32. ↑ 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.
  33. ↑ Chisholm, Hugh, ed. (1911). "Cambria"  . Encyclopædia Britannica (11th ed.). Cambridge University Press.
  34. ↑ 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.
  35. ↑ "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.
  36. 1 2 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.
  37. 1 2 3 4 5 6 7 8 9 10 11 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.
  38. ↑ Sivin, Nathan (1995). Science in ancient China: researches and reflections. Variorum. ISBN   0-86078-492-4. OCLC   956775994.
  39. ↑ Adams, Frank D. (1938). The Birth and Development of the Geological Sciences. Williams & Wilkins. ISBN   0-486-26372-X. OCLC   165626104.
  40. ↑ 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.
  41. ↑ McCurdy, Edward (1938). The notebooks of Leonardo da Vinci. New York: Reynal & Hitchcock. OCLC   2233803.
  42. ↑ 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
  43. ↑ 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.
  44. ↑ Moro, Anton Lazzaro (1740). De'crostacei e degli altri marini corpi che si truovano su'monti (in Italian). Appresso Stefano Monti.
  45. ↑ 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.
  46. ↑ Hutton, James (1795). Theory of the Earth. Vol. 2. Edinburgh.
  47. ↑ Playfair, John (1802). Illustrations of the Huttonian theory of the earth. Digitised by London Natural History Museum Library. Edinburgh: Neill & Co.
  48. ↑ 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.
  49. ↑ 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.
  50. ↑ Holmes, Arthur (1913). The age of the earth. Gerstein - University of Toronto. London, Harper.
  51. 1 2 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.
  52. ↑ 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.
  53. ↑ 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.
  54. ↑ "A Revised Geological Time-Scale". Nature. 187 (4731): 27–28. 1960. Bibcode:1960Natur.187T..27.. doi: 10.1038/187027d0 . ISSN   0028-0836. S2CID   4179334.
  55. ↑ 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.
  56. ↑ 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.
  57. ↑ W. B. Harland (1982). A geologic time scale. Cambridge [England]: Cambridge University Press. ISBN   0-521-24728-4. OCLC   8387993.
  58. ↑ W. B. Harland (1990). A geologic time scale 1989. Cambridge: Cambridge University Press. ISBN   0-521-38361-7. OCLC   20930970.
  59. ↑ 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.
  60. ↑ 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.
  61. 1 2 3 4 5 6 7 8 9 10 11 12 13 F. M. Gradstein (2012). The geologic time scale 2012. Volume 2 (1st ed.). Amsterdam: Elsevier. ISBN   978-0-444-59448-8. OCLC   808340848.
  62. 1 2 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.
  63. 1 2 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)
  64. ↑ 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, vol. 1, Cham: Springer International Publishing, pp. 19–21, doi:10.1007/978-3-030-82202-6_2, ISBN   978-3-030-82201-9, S2CID   245639062 , retrieved 15 April 2022
  65. ↑ "Working Group on the 'Anthropocene' | Subcommission on Quaternary Stratigraphy". Archived from the original on 7 April 2022. Retrieved 17 April 2022.
  66. ↑ 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.
  67. ↑ 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.
  68. ↑ 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.
  69. ↑ 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.
  70. ↑ 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.
  71. ↑ 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
  72. ↑ 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
  73. ↑ Van Kranendonk, Martin J. (2012). "A Chronostratigraphic Division of the Precambrian". 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.
  74. 1 2 3 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 .
  75. ↑ 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. Archived (PDF) from the original on 19 April 2012.
  76. ↑ 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.
  77. ↑ 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 ]
  78. ↑ "Geological time scale". Digital Atlas of Ancient Life. Paleontological Research Institution. Retrieved 17 January 2022.
  79. ↑ "International Commission on Stratigraphy". International Geological Time Scale. Retrieved 5 June 2022.
  80. ↑ "Geologic Timescale Elements in the International Chronostratigraphic Chart" . Retrieved 3 August 2014.
  81. ↑ Cox, Simon J. D. "SPARQL endpoint for CGI timescale service". Archived from the original on 6 August 2014. Retrieved 3 August 2014.
  82. ↑ 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.
  83. ↑ 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.
  84. ↑ 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 .
  85. 1 2 Tyson, Peter (October 2009). "NOVA, Aliens from Earth: Who's who in human evolution". PBS. Retrieved 8 October 2009.
  86. ↑ 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.
  87. 1 2 3 4 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.
  88. ↑ "Here's What the Last Common Ancestor of Apes and Humans Looked Like". Live Science . 10 August 2017.
  89. ↑ 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.
  90. ↑ 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.
  91. ↑ 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.
  92. ↑ 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.
  93. ↑ Naranjo-Ortiz, Miguel A.; Gabaldón, Toni (25 April 2019). "Fungal evolution: major ecological adaptations and evolutionary transitions". Biological Reviews of the Cambridge Philosophical Society . 94 (4). Cambridge Philosophical Society (Wiley): 1443–1476. doi:10.1111/brv.12510. ISSN   1464-7931. PMC   6850671 . PMID   31021528. S2CID   131775942.
  94. ↑ 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.
  95. ↑ 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.
  96. ↑ Och, Lawrence M.; Shields-Zhou, Graham A. (1 January 2012). "The Neoproterozoic oxygenation event: Environmental perturbations and biogeochemical cycling". Earth-Science Reviews. 110 (1–4): 26–57. doi:10.1016/j.earscirev.2011.09.004.
  97. ↑ 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.
  98. ↑ 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, vol. 15, Elsevier, pp. 127–147, doi:10.1016/s0166-2635(07)15031-3, ISBN   978-0-444-52810-0 , retrieved 1 May 2022
  99. ↑ 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.
  100. ↑ Wilhelms, Don E. (1987). The geologic history of the Moon. Professional Paper. United States Geological Survey. doi:10.3133/pp1348.
  101. ↑ 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.
  102. ↑ 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.
  103. ↑ 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

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.