Geologic time scaleFrom Wikipedia, the free encyclopedia

This clock representation shows some of the major units of geological time and definitive events of Earth history. The

Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as

4.0 Ga(billion years ago).[1] Other subdivisions reflect the evolution of life; the Archean and Proterozoic are both eons, the

Palaeozoic, Mesozoic and Cenozoic are eras of the Phanerozoic eon. The two million year Quaternary period, the time of

recognizable humans, is too small to be visible at this scale.

The geologic time scale (GTS) is a system of chronological measurement that relates stratigraphy to time,

and is used by geologists, paleontologists, and other earth scientists to describe the timing and relationships

between events that have occurred throughout Earth's history. The table of geologic time spans presented here

agrees with thenomenclature, dates and standard color codes set forth by the International Commission on

Stratigraphy.

Evidence from radiometric dating indicates that the Earth is about 4.54 billion years old. The geology or deep

time of Earth's past has been organized into various units according to events which took place in each period.

Different spans of time on the GTS are usually delimited by changes in the composition of strata which

correspond to them, indicating major geological or paleontological events, such as mass extinctions. For

example, the boundary between theCretaceous period and the Paleogene period is defined by

the Cretaceous–Paleogene extinction event, which marked the demise of the dinosaurs and many other groups

of life. Older time spans which predate the reliable fossil record (before the Proterozoic Eon ) are defined by the

absolute age.

Contents

  [hide] 

1 Terminology

2 History and nomenclature of the time scale

3 Condensed graphical timelines

4 Table of geologic time

o 4.1 Proposed Precambrian timeline

5 See also

6 Notes and references

7 Further reading

8 External links

Terminology[edit]

e  h

Units in geochronology and stratigraphy[2]

Segments of rock (strata) inchronostratigraphy

Time spans ingeochronology

Notes togeochronological units

Eonothem Eon4 total, half a billion years or more

Erathem Era10 total, several hundred million years

System Period

Series Epoch tens of millions of years

Stage Age millions of years

Chronozone Chronsubdivision of an age, not used by the ICS timescale

The largest defined unit of time is the supereon, composed of eons. Eons are divided into eras, which are in

turn divided into periods, epochs and ages. The terms eonothem, erathem, system, series, and stage are

used to refer to the layers of rock that correspond to these periods of geologic time in earth's history.

Geologists qualify these units as Early, Mid, and Late when referring to time, and Lower, Middle, and Upper

when referring to the corresponding rocks. For example, the Lower Jurassic Series

in chronostratigraphy corresponds to the Early Jurassic Epoch in geochronology.[3] The adjectives are

capitalized when the subdivision is formally recognized, and lower case when not; thus "early Miocene" but

"Early Jurassic."

Geologic units from the same time but different parts of the world often look different and contain different

fossils, so the same period was historically given different names in different locales. For example, in North

America the Lower Cambrian is called the Waucoban series that is then subdivided into zones based on

succession of trilobites. In East Asia and Siberia, the same unit is split into Alexian, Atdabanian,

and Botomian stages. A key aspect of the work of the International Commission on Stratigraphy is to reconcile

this conflicting terminology and define universal horizons that can be used around the world.[4]

History and nomenclature of the time scale[edit]

Main articles: History of geology and History of paleontology

Graphical representation of Earth's history as a spiral

A comparative geological timescale

In Ancient Greece, Aristotle saw that fossil seashells from rocks were similar to those found on the beach and

inferred that the fossils were once part of living animals. He reasoned that the positions of land and sea had

changed over long periods of time. Leonardo da Vinci concurred with Aristotle's view that fossils were the

remains of ancient life.[5]

The 11th-century Persian geologist Avicenna (Ibn Sina) and the 13th century Dominican bishop Albertus

Magnus (Albert of Saxony) extended Aristotle's explanation into a theory of a petrifying fluid.[6] Avicenna also

first proposed one of the principles underlying geologic time scales, the law of superposition of strata, while

discussing the origins of mountains in The Book of Healing in 1027.[7][8] The Chinese naturalist Shen

Kuo (1031–1095) also recognized the concept of 'deep time'.[9]

The principles underlying geologic (geological) time scales were later laid down by Nicholas Steno in the late

17th century. Steno argued that rock layers (or strata) are laid down in succession, and that each represents a

"slice" of time. He also formulated the law of superposition, which states that any given stratum is probably

older than those above it and younger than those below it. While Steno's principles were simple, applying them

to real rocks proved complex. Over the course of the 18th century geologists realized that:

1. Sequences of strata were often eroded, distorted, tilted, or even

inverted after deposition;

2. Strata laid down at the same time in different areas could have entirely

different appearances;

3. The strata of any given area represented only part of the Earth's long

history.

The first serious attempts to formulate a geological time scale that could be applied anywhere on Earth were

made in the late 18th century. The most influential of those early attempts (championed by Abraham Werner,

among others) divided the rocks of the Earth's crust into four types: Primary, Secondary, Tertiary, and

Quaternary. Each type of rock, according to the theory, formed during a specific period in Earth history. It was

thus possible to speak of a "Tertiary Period" as well as of "Tertiary Rocks." Indeed, "Tertiary" (now Paleocene -

Pliocene) and "Quaternary" (now Pleistocene and Holocene) remained in use as names of geological periods

well into the 20th century.

The Neptunist theories popular at this time (expounded by Werner) proposed that all rocks had precipitated out

of a single enormous flood. A major shift in thinking came when James Hutton presented his Theory of the

Earth; or, an Investigation of the Laws Observable in the Composition, Dissolution, and Restoration of Land

Upon the Globe before the Royal Society of Edinburgh in March and April 1785. It has been said that "as things

appear from the perspective of the 20th century, James Hutton in those readings became the founder of

modern geology"[10] Hutton proposed that the interior of the Earth was hot, and that this heat was the engine

which drove the creation of new rock: land was eroded by air and water and deposited as layers in the sea;

heat then consolidated the sediment into stone, and uplifted it into new lands. This theory was dubbed

"Plutonist" in contrast to the "Neptunist" flood-oriented theory.

The identification of strata by the fossils they contained, pioneered by William Smith, Georges Cuvier, Jean

d'Omalius d'Halloy, and Alexandre Brogniart  in the early 19th century, enabled geologists to divide Earth

history more precisely. It also enabled them to correlate strata across national (or even continental) boundaries.

If two strata (however distant in space or different in composition) contained the same fossils, chances were

good that they had been laid down at the same time. Detailed studies between 1820 and 1850 of the strata and

fossils of Europe produced the sequence of geological periods still used today.

The process was dominated by British geologists, and the names of the periods reflect that dominance. The

"Cambrian", (the classical name for Wales) and the "Ordovician", and "Silurian", named after ancient Welsh

tribes, were periods defined using stratigraphic sequences from Wales.[11] The "Devonian" was named for the

English county of Devon, and the name "Carboniferous" was simply an adaptation of "the Coal Measures", the

old British geologists' term for the same set of strata. The "Permian" was named after Perm, Russia, because it

was defined using strata in that region by Scottish geologist Roderick Murchison. However, some periods were

defined by geologists from other countries. The "Triassic" was named in 1834 by a German geologist Friedrich

Von Alberti from the three distinct layers (Latin trias meaning triad) —red beds, capped by chalk, followed by

black shales— that are found throughout Germany and Northwest Europe, called the 'Trias'. The "Jurassic"

was named by a French geologist Alexandre Brogniart for the extensive marine limestone exposures of

the Jura Mountains. The "Cretaceous" (from Latin creta meaning 'chalk') as a separate period was first defined

by Belgian geologist Jean d'Omalius d'Halloy in 1822, using strata in the Paris basin [12]  and named for the

extensive beds of chalk (calcium carbonate deposited by the shells of marine invertebrates).

British geologists were also responsible for the grouping of periods into Eras and the subdivision of the Tertiary

and Quaternary periods into epochs. In 1841 John Phillips published the first global geological time scale

based on the types of fossils found in each era. Phillips' scale helped standardize the use of terms

like Paleozoic ("old life") which he extended to cover a larger period than it had in previous usage,

and Mesozoic ("middle life") which he invented.[13]

When William Smith and Sir Charles Lyell first recognized that rock strata represented successive time periods,

time scales could be estimated only very imprecisely since various kinds of rates of change used in estimation

were highly variable. While creationists had been proposing dates of around six or seven thousand years for

the age of the Earth based on the Bible, early geologists were suggesting millions of years for geologic periods

with some even suggesting a virtually infinite age for the Earth. Geologists and paleontologists constructed the

geologic table based on the relative positions of different strata and fossils, and estimated the time scales

based on studying rates of various kinds of weathering, erosion, sedimentation, and lithification. Until the

discovery ofradioactivity in 1896 and the development of its geological applications through radiometric

dating during the first half of the 20th century (pioneered by such geologists as Arthur Holmes) which allowed

for more precise absolute dating of rocks, the ages of various rock strata and the age of the Earth were the

subject of considerable debate.

The first geologic time scale that included absolute dates was published in 1913 by the British geologist Arthur

Holmes.[14] He greatly furthered the newly created discipline of geochronology and published the world

renowned book The Age of the Earth in which he estimated the Earth's age to be at least 1.6 billion years.[15]

In 1977, the Global Commission on Stratigraphy (now the International Commission on Stratigraphy) started an

effort to define global references known as GSSP (Global Boundary Stratotype Sections and Point)s for

geologic periods and faunal stages. The commission's most recent work is described in the 2004 geologic time

scale of Gradstein et al.[16] A UML model for how the timescale is structured, relating it to the GSSP, is also

available.[17]

Condensed graphical timelines[edit]

The following four timelines show the geologic time scale. The first shows the entire time from the formation of

the Earth to the present, but this compresses the most recent eon. Therefore the second scale shows the most

recent eon with an expanded scale. The second scale compresses the most recent era, so the most recent era

is expanded in the third scale. Since theQuaternary is a very short period with short epochs, it is further

expanded in the fourth scale. The second, third, and fourth timelines are therefore each subsections of their

preceding timeline as indicated by asterisks. The Holocene (the latest epoch) is too small to be shown clearly

on the third timeline on the right, another reason for expanding the fourth scale. The Pleistocene (P) epoch. Q

stands for the Quaternary period.

Millions of Years

Table of geologic time[edit]

The following table summarizes the major events and characteristics of the periods of time making up the

geologic time scale. As above, this time scale is based on the International Commission on Stratigraphy.

(See lunar geologic timescale for a discussion of the geologic subdivisions of Earth's moon.) This table is

arranged with the most recent geologic periods at the top, and the most ancient at the bottom. The height of

each table entry does not correspond to the duration of each subdivision of time.

The content of the table is based on the current official geologic time scale of the International Commission on

Stratigraphy,[18] with the epoch names altered to the early/late format from lower/upper as recommended by the

ICS when dealing with chronostratigraphy.[3]

V

T

E

Geologic time scale[hide]

Supereo

Eon Era Period [19]

Epoch Age [20] Major events Start,

n

million

years ago[20]

n/a[21]

Phanerozoic

Cenozoic [22]

Quaternary

Holocene

chrons: Subatlantic 

·Subboreal · Atlantic ·Borea

l · Preboreal

Quaternary Ice Age recedes, and the current interglacial begins; rise of human civilization.Sahara forms from savannah, and agriculture begins. Stone Age cultures give way toBronze Age (3300 BC) and Iron Age (1200 BC), giving rise to many pre-historic culturesthroughout the world. Little Ice Age (stadial) causes brief cooling in Northern Hemispherefrom 1400 to 1850. Following the Industrial Revolution, Atmospheric CO2 levels rise from around 280 parts per million volume (ppmv) to the current level of 400[23] ppmv.[24][25]

0.0117[26]

Pleistocene

Late (locally Tarantian ·Tyrrhenian · Eemian ·Sangamonian)

Flourishing and then extinction of many large mammals (Pleistocene megafauna). Evolution of anatomically modern humans. Quaternary Ice Age continues with glaciationsand interstadials (and the accompanying fluctuations from 100 to 300 ppmv inatmospheric CO2 levels[24][25]), further intensification of Icehouse Earth conditions, roughly 1.6 Ma. Last glacial maximum (30000 years ago), last glacial period (18000–15000 years ago). Dawn of human stone-age cultures, with increasing technical complexity relative to previous ice age cultures, such as engravings and clay statues (e.g.Venus of Lespugue), particularly in the Mediterranean and Europe. Lake Toba supervolcano  erupts 75000 years before present, causing a volcanic winter that pushes humanity to the brink of extinction. Pleistocene ends with Oldest Dryas, Older Dryas/Allerød and Younger Dryas climate events, with Younger Dryas forming the boundary with the Holocene.

0.126

Middle (formerly Ionian) 0.781

Calabrian1.806*

Gelasian2.588*

Neogene

Pliocene

Piacenzian/BlancanIntensification of present Icehouse conditions, present (Quaternary) ice age begins roughly 2.58 Ma; cool and dry climate. Australopithecines, many of the existing genera of mammals, and recent mollusks appear. Homo habilis appears.

3.600*

Zanclean5.333*

Miocene

MessinianModerate Icehouse climate, punctuated by ice ages; Orogeny in northern hemisphere. Modern mammal and bird families become recognizable. Horses and mastodonsdiverse. Grasses become ubiquitous. First apes appear (for reference see the article: "Sahelanthropus tchadensis"). Kaikoura Orogeny  forms Southern Alps in New Zealand, continues today. Orogeny of the Alps in Europe slows, but continues to this day.Carpathian orogeny forms Carpathian Mountains in Central and Eastern Europe. Hellenic orogeny in Greece and Aegean Sea slows, but continues to this day. Middle Miocene Disruption occurs. Widespread forests slowly draw in massive amounts of CO2, gradually lowering the level of atmospheric CO2 from 650 ppmv down to

7.246*

Tortonian11.62*

Serravallian13.82*

Langhian 15.97

Burdigalian 20.44

Aquitanian 23.03*

around 100 ppmv.[24][25]

Paleogene

Oligocene

Chattian Warm but cooling climate, moving towards Icehouse; Rapid evolution and diversification of fauna, especially mammals. Major evolution and dispersal of modern types offlowering plants

28.1

Rupelian 33.9*

Eocene

Priabonian Moderate, cooling climate. Archaic mammals (e.g. Creodonts, Condylarths, Uintatheres, etc) flourish and continue to develop during the epoch. Appearance of several "modern" mammal families. Primitive whales diversify. First grasses. Reglaciation of Antarctica and formation of its ice cap; Azolla event  triggers ice age, and the Icehouse Earth climate that would follow it to this day, from the settlement and decay of seafloor algae drawing in massive amounts of atmospheric carbon dioxide,[24]

[25] lowering it from 3800 ppmvdown to 650 ppmv. End of Laramide and Sevier Orogenies of the Rocky Mountains in North America. Orogeny of the Alps in Europe begins. Hellenic Orogeny begins in Greece and Aegean Sea.

38.0

Bartonian 41.3

Lutetian 47.8*

Ypresian 56.0*

Paleocene

Thanetian Climate tropical. Modern plants appear; Mammals diversify into a number of primitive lineages following the extinction of the dinosaurs. First large mammals (up to bear or small hippo size). Alpine orogeny in Europe and Asia begins. Indian Subcontinentcollides with Asia 55 Ma, Himalayan Orogeny starts between 52 and 48 Ma.

59.2*

Selandian 61.6*

Danian 66.0*

Mesozoic

Cretaceous

Late

Maastrichtian

Flowering plants proliferate, along with new types of insects. More modern teleost fish begin to appear. Ammonoidea, belemnites, rudist bivalves, echinoids and sponges all common. Many new types of dinosaurs (e.g. Tyrannosaurs, Titanosaurs, duck bills, andhorned dinosaurs) evolve on land, as do Eusuchia (modern crocodilians); andmosasaurs and modern sharks appear in the sea. Primitive birds gradually replacepterosaurs. Monotremes, marsupials and placental mammals appear. Break up ofGondwana. Beginning of Laramide and Sevier Orogenies of the Rocky Mountains.Atmospheric CO2 close to present-day levels.

72.1 ± 0.2*

Campanian83.6 ± 0.2

Santonian86.3 ± 0.5

Coniacian89.8 ± 0.3

Turonian 93.9*

Cenomanian100.5*

Early

Albianc. 113.0

Aptianc. 125.0

Barremianc. 129.4

Hauterivianc. 132.9

Valanginianc. 139.8

Berriasianc. 145.0

Juras Late Tithonian Gymnosperms (especially conifers, Bennettitales and  152.1

sic

cycads) and ferns common. Many types of dinosaurs, such as sauropods, carnosaurs, and stegosaurs. Mammals common but small. First birds and lizards. Ichthyosaurs and plesiosaurs diverse.Bivalves, Ammonites and belemnites abundant. Sea urchins very common, along withcrinoids, starfish, sponges, and terebratulid and rhynchonellid brachiopods. Breakup ofPangaea into Gondwana and Laurasia. Nevadan orogeny in North America. Rantigataand Cimmerian Orogenies taper off. Atmospheric CO2 levels 4–5 times the present day levels (1200–1500 ppmv, compared to today's 385 ppmv[24][25]).

± 0.9

Kimmeridgian157.3 ± 1.0

Oxfordian163.5 ± 1.0

Middle

Callovian166.1 ± 1.2

Bathonian168.3 ± 1.3*

Bajocian170.3 ± 1.4*

Aalenian174.1 ± 1.0*

Early

Toarcian182.7 ± 0.7

Pliensbachian190.8 ± 1.0*

Sinemurian199.3 ± 0.3*

Hettangian201.3 ± 0.2*

Triassic

Late

RhaetianArchosaurs dominant on land as dinosaurs, in the oceans as Ichthyosaurs andnothosaurs, and in the air as pterosaurs. Cynodonts become smaller and more mammal-like, while first mammals and crocodilia appear. Dicroidiumflora common on land. Many large aquatic temnospondyl amphibians. Ceratitic ammonoids extremely common. Modern corals and teleost fish appear, as do many modern insect clades.Andean Orogeny in South America. Cimmerian Orogeny in Asia. Rangitata Orogenybegins in New Zealand. Hunter-Bowen Orogeny in Northern Australia, Queensland andNew South Wales ends, (c. 260–225 Ma)

c. 208.5

Norianc. 228

Carnianc. 235*

MiddleLadinian

c. 242*

Anisian 247.2

Early

Olenekian 251.2

Induan252.2 ± 0.5*

Paleozoic

Permian

Lopingian

ChanghsingianLandmasses unite into supercontinent Pangaea, creating the Appalachians. End of Permo-Carboniferous glaciation. Synapsid reptiles (pelycosaurs and therapsids) become plentiful, while parareptiles and temnospondyl amphibians remain common. In the mid-Permian, coal-age flora are replaced by cone-bearing gymnosperms (the first true seed plants) and by the first true mosses. Beetles and flies evolve. Marine life flourishes in warm shallow

254.2 ± 0.1*

Wuchiapingian259.9 ± 0.4*

Guadalupian Capitanian

265.1 ± 0.4*

Wordian/Kazanian 268.8

reefs; productid and spiriferid brachiopods, bivalves, forams, and ammonoids all abundant. Permian-Triassic extinction event occurs 251Ma: 95% of life on Earth becomes extinct, including all trilobites, graptolites, and blastoids. Ouachitaand 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–

± 0.5*

Roadian/Ufimian272.3 ± 0.5*

Cisuralian

Kungurian279.3 ± 0.6

Artinskian290.1 ± 0.1

Sakmarian295.5 ± 0.4

Asselian298.9 ± 0.2*

Carbon-iferous [27]

Pennsylvanian

GzhelianWinged insects radiate suddenly; some (esp. Protodonata and Palaeodictyoptera) are quite large. Amphibians common and diverse. First reptiles and coal forests (scale trees, ferns, club trees, giant horsetails, Cordaites, etc.). Highest-ever atmospheric oxygenlevels. Goniatites, brachiopods, bryozoa, bivalves, and corals plentiful in the seas and oceans. Testate forams proliferate. Uralian orogeny in Europe and Asia. Variscan orogeny  occurs towards middle and late Mississippian Periods.

303.7 ± 0.1

Kasimovian307.0 ± 0.1

Moscovian315.2 ± 0.2

Bashkirian323.2 ± 0.4*

Mississippian

SerpukhovianLarge primitive trees, first land vertebrates, and amphibious sea-scorpions live amidcoal-forming coastal swamps. Lobe-finned rhizodonts are dominant big fresh-water predators. In the oceans, early sharks are common and quite diverse; echinoderms(especially crinoids and blastoids) abundant. Corals, bryozoa, goniatites and brachiopods (Productida, Spiriferida, etc.) very common, but trilobites and nautiloidsdecline. Glaciation in East Gondwana. Tuhua Orogeny  in New Zealand tapers off.

330.9 ± 0.2

Viséan346.7 ± 0.4*

Tournaisian358.9 ± 0.4*

Devonian

Late

FamennianFirst clubmosses, horsetails and ferns appear, as do the first seed-bearing plants (progymnosperms), first trees (the progymnosperm Archaeopteris), and first (wingless)insects. Strophomenid and atrypid brachiopods, rugose and tabulate corals, and crinoidsare all abundant in the oceans. Goniatite ammonoids are plentiful, while squid-likecoleoids arise. Trilobites and armoured agnaths decline, while jawed fishes (placoderms, lobe-finned and ray-finned fish, and early sharks) rule the seas. Firstamphibians still aquatic. "Old Red Continent" of Euramerica. Beginning of Acadian Orogeny for Anti-Atlas Mountains of North Africa, and Appalachian Mountains of North America, also the Antler, Variscan, and Tuhua Orogeny  in New Zealand.

372.2 ± 1.6*

Frasnian382.7 ± 1.6*

Middle

Givetian387.7 ± 0.8*

Eifelian393.3 ± 1.2*

EarlyEmsian

407.6 ± 2.6*

Pragian 410.8 ± 2.8*

Lochkovian419.2 ± 3.2*

Silurian

Pridoli

First Vascular plants (the rhyniophytes and their relatives), first millipedes andarthropleurids on land. First jawed fishes, as well as many armoured jawless fish, populate the seas. Sea-scorpions reach large size. Tabulate and rugose corals,brachiopods (Pentamerida, Rhynchonellida, etc.), and crinoids all abundant. Trilobitesand mollusks diverse; graptolites not as varied. Beginning of Caledonian Orogeny for hills in England, Ireland, Wales, Scotland, and the Scandinavian Mountains. Also continued into Devonian period as the Acadian Orogeny, above. Taconic Orogeny tapers off. Lachlan Orogeny on Australian Continent tapers off.

423.0 ± 2.3*

Ludlow/Cayugan

Ludfordian425.6 ± 0.9*

Gorstian427.4 ± 0.5*

Wenlock

Homerian/Lockportian430.5 ± 0.7*

Sheinwoodian/Tonawandan433.4 ± 0.8*

Llandovery/Alexandrian

Telychian/Ontarian438.5 ± 1.1*

Aeronian440.8 ± 1.2*

Rhuddanian443.4 ± 1.5*

Ordovician

Late

Hirnantian

Invertebrates diversify into many new types (e.g., long straight-shelled cephalopods). Early corals, articulate brachiopods (Orthida, Strophomenida, etc.), bivalves, nautiloids,trilobites, ostracods, bryozoa, many types of echinoderms (crinoids, cystoids, starfish, etc.), branched graptolites, and other taxa all common. Conodonts (early planktonic vertebrates ) appear. First green plants and fungi on land. Ice age at end of period.

445.2 ± 1.4*

Katian453.0 ± 0.7*

Sandbian458.4 ± 0.9*

Middle

Darriwilian467.3 ± 1.1*

Dapingian470.0 ± 1.4*

Early

Floian(formerly Arenig)

477.7 ± 1.4*

Tremadocian485.4 ± 1.9*

Cambrian

Furongian

Stage 10Major diversification of life in the Cambrian Explosion. Numerous fossils; most modernanimal phyla appear. First chordates appear, along with a number of extinct, problematic phyla.

c. 489.5

Jiangshanian c. 494*

Reef-building Archaeocyatha abundant; then vanish. Trilobites, priapulid worms,sponges, inarticulate brachiopods (unhinged lampshells), and many other animals numerous. Anomalocarids are giant predators, while many Ediacaran fauna die out.Prokaryotes, protists (e.g., forams), fungi and algae continue to present day. Gondwanaemerges. Petermann Orogeny  on the Australian Continent tapers off (550–535 Ma). Ross Orogeny in Antarctica. Adelaide Geosyncline (Delamerian Orogeny), majority of orogenic activity from 514–500Ma. Lachlan Orogeny on Australian

Paibianc. 497*

Series 3

Guzhangianc. 500.5*

Drumianc. 504.5*

Stage 5c. 509

Series 2

Stage 4c. 514

Stage 3c. 521

Terreneuvian

Stage 2c. 529

Fortunian541.0 ± 1.0*

Precam-brian [28]

Proter-ozoic [29]

Neo-proterozoic [29]

Ediacaran

Good fossils of the first multi-celled animals. Ediacaran biota  flourish worldwide in seas. Simple trace fossils of possible worm-likeTrichophycus, etc. First sponges and trilobitomorphs. Enigmatic forms include many soft-jellied creatures shaped like bags, disks, or quilts (likeDickinsonia). Taconic Orogeny in North America. Aravalli Range  orogeny in Indian Subcontinent. Beginning of Petermann Orogeny on Australian Continent. Beardmore Orogeny in Antarctica, 633–620Ma.

c. 635*

Cryogenian

Possible "Snowball Earth" period. Fossils still rare. Rodinia landmass begins to break up. Late Ruker / Nimrod Orogeny in Antarctica tapers off.

850[30]

Tonian

Rodinia supercontinent persists. Trace fossils of simple multi-celled eukaryotes. First radiation of dinoflagellate-like acritarchs. Grenville Orogeny tapers off in North America. Pan-African orogeny in Africa. Lake Ruker / Nimrod Orogeny in Antarctica, 1000 ± 150 Ma. Edmundian Orogeny (c. 920 - 850Ma), Gascoyne Complex , Western Australia. Adelaide Geosyncline laid down on Australian Continent, beginning of Adelaide Geosyncline (Delamerian Orogeny) in that continent.

1000[30]

Meso-proterozoic [29]

Stenian

Narrow highly metamorphic belts due to orogeny as Rodinia forms. Late Ruker / Nimrod Orogeny in Antarctica possibly begins. Musgrave Orogeny (c. 1080 Ma), Musgrave Block, Central Australia.

1200[30]

Ectasian

Platform covers continue to expand. Green algae colonies in the seas. Grenville Orogeny in North America.

1400[30]

Calymmian

Platform covers expand. Barramundi Orogeny, McArthur Basin, Northern Australia, and Isan Orogeny, c.1600 Ma, Mount Isa Block, Queensland

1600[30]

Paleo-proterozoic [29]

Statherian

First complex single-celled life: protists with nuclei. Columbia is the primordial supercontinent. Kimban Orogeny in Australian Continent ends. Yapungku Orogeny on Yilgarn craton , in Western Australia. Mangaroon Orogeny, 1680–1620 Ma, on the Gascoyne Complex  in Western Australia. Kararan Orogeny (1650-Ma), Gawler Craton, South Australia.

1800[30]

Orosirian

The atmosphere becomes oxygenic. Vredefort and Sudbury Basin asteroid impacts. Much orogeny. Penokean and Trans-Hudsonian Orogenies in North America. Early Ruker Orogeny in Antarctica, 2000 - 1700 Ma. Glenburgh Orogeny, Glenburgh Terrane , Australian Continent c. 2005–1920 Ma. Kimban Orogeny, Gawler craton  in Australian Continent begins.

2050[30]

Rhya Bushveld Igneous Complex forms. Huronian glaciation. 230

cian 0[30]

Siderian

Oxygen catastrophe: banded iron formations forms. Sleaford Orogeny on Australian Continent, Gawler Craton  2440–2420 Ma.

2500[30]

Archean [29 ]

Neoarchean [29]

Stabilization of most modern cratons; possible mantle overturn event. Insell Orogeny, 2650 ± 150 Ma. Abitibi greenstone belt in present-day Ontarioand Quebec begins to form, stablizes by 2600 Ma.

2800[30]

Mesoarchean [2 9]

First stromatolites (probably colonial cyanobacteria). Oldest macrofossils. Humboldt Orogeny in Antarctica. Blake River Megacaldera Complex begins to form in present-day Ontario and Quebec, ends by roughly 2696Ma.

3200[30]

Paleoarchean [2 9]

First known oxygen-producing bacteria. Oldest definitive microfossils. Oldest cratons on Earth (such as the Canadian Shield and the Pilbara Craton) may have formed during this period[31]. Rayner Orogeny in Antarctica.

3600[30]

Eoarchean [29]

Simple single-celled life (probably bacteria and archaea). Oldest probable microfossils. 4000

Hadean[29][32]

Early Imbrian [29] [33]

Indirect photosynthetic evidence (e.g., kerogen) of primordial life. This era overlaps the end of the Late Heavy Bombardment of the inner solar system.

c.4100

Nectarian [29] [33]

This unit gets its name from the lunar geologic timescale when the Nectaris Basin  and other greater lunar basins form by big impact events.

c.4300

Basin Groups [29] [33]

Oldest known rock (4030 Ma)[34]. The first life forms and self-replicating RNA molecules evolve around 4000 Ma, after the Late Heavy Bombardmentends on Earth. Napier Orogeny in Antarctica, 4000 ± 200 Ma.

c.4500

Cryptic [29] [33]

Oldest known mineral (Zircon, 4404 ± 8 Ma).[35] Formation of Moon(4533 Ma), probably from giant impact. Formation of Earth (4567.17 to 4570Ma)

c.4567

Proposed Precambrian timeline[edit]

The ICS's Geologic Time Scale 2012 book which includes the new approved time scale also displays a

proposal to substantially revise the Precambrian time scale to reflect important events such as the formation of

the Earth or the Great Oxidation Event, among others, while at the same time maintaining most of the previous

chronostratigraphic nomenclature for the pertinent time span.[36]

Hadean  Eon - 4567–4030 MYA

Chaotian  Era - 4567–4404 MYA - the name alluding both to

the mythological Chaos and the chaotic phase of planet formation [36] [37]

[38]

Jack Hillsian  or Zirconian Era - 4404–4030 MYA - both names allude

to the Jack Hills Greenstone Belt which provided the oldest mineral

grains on Earth, zircons [36] [37]

Archean  Eon - 4030–2420 MYA

Paleoarchean  Era - 4030–3490 MYA

Acastan  Period - 4030–3810 MYA - named after the Acasta

Gneiss [36] [37]

Isuan  Period - 3810–3490 MYA - named after the Isua

Greenstone Belt [36]

Mesoarchean  Era - 3490–2780 MYA

Vaalbaran  Period - 3490–3020 MYA - a portmanteau based on

the names of the Kapvaal (Southern Africa) and Pilbara (Western

Australia) cratons [36]

Pongolan  Period - 3020–2780 MYA - named after the Pongola

Supergroup [36]

Neoarchean  Era - 2780–2420 MYA

Methanian  Period - 2780–2630 MYA - named for the inferred

predominance of methanotrophic prokaryotes [36]

Siderian  Period - 2630–2420 MYA - named for the voluminous

banded iron formations formed within its duration[36]

Proterozoic  Eon - 2420–541 MYA

Paleoproterozoic  Era - 2420–1780 MYA

Oxygenian  Period - 2420–2250 MYA - named for displaying the

first evidence for a global oxidizing atmosphere[36]

Jatulian  or Eukaryian Period - 2250–2060 MYA - names are

respectively for the Lomagundi-Jatuli δ13C isotopic excursion

event spanning its duration, and for the first fossil appearance

of eukaryotes [36]

Columbian  Period - 2060–1780 MYA - named after the

supercontinent Columbia [36]

Mesoproterozoic  Era - 1780–850 MYA

Rodinian  Period - 1780–850 MYA - named after the

supercontinent Rodinia, stable environment[36]

Neoproterozoic  Era - 850–541 MYA

Cryogenian  Period - 850–635 MYA - named for the occurrence of

several glaciations[36]

Ediacaran  Period - 635–541 MYA

Shown to scale:

Compare with the current official one:

See also[edit]

Age of the Earth

Anthropocene

Bubnoff unit

Deep time

Evolutionary history of life

Geological history of Earth

Geology of Mars /areology

Graphical timeline of the universe

History of the Earth

History of geology

History of paleontology

List of fossil sites

Logarithmic timeline

Lunar 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 paleontology

Notes and references[edit]

1. Jump up^ International Commission on Stratigraphy

2008:stratigraphy.org

 

, retrieved 9 March 2009.

2. Jump up^ Cohen, K.M., Finney, S., Gibbard, P.L. (2013), International

Chronostratigraphic Chart

 

, International Commission on Stratigraphy.

3. ^ Jump up to:a b International Commission on Stratigraphy.

"Chronostratigraphic Units." International Stratigraphic Guide. Accessed

14 December 2009. stratigraphy.org

 

4. Jump up^ Statutes of the International Commission on Stratigraphy

 

, retrieved 26 November 2009

5. Jump up^ Correlating Earth's History

 

, Paul R. Janke

6. Jump up^ Rudwick, M. J. S. (1985), The Meaning of Fossils: Episodes in

the History of Palaeontology, University of Chicago Press, p. 24, ISBN 0-

226-73103-0

7. Jump up^ Fischer, Alfred G.; Garrison, Robert E. (2009), "The role of the

Mediterranean region in the development of sedimentary geology: A

historical overview", Sedimentology 56: 3,Bibcode:2009Sedim..56....3F

 

, doi:10.1111/j.1365-3091.2008.01009.x

 

.

8. Jump up^ Quoted in The contribution of Ibn Sina (Avicenna) to the

development of the Earth Sciences

 

, among other sources

9. Jump up^ Sivin, Nathan (1995), Science in Ancient China: Researches

and Reflections, Brookfield, Vermont: Ashgate Publishing Variorum series,

III, 23–24

10. Jump up^ John McPhee, Basin and Range, New York:Farrar, Straus and

Giroux, 1981, pp.95-100.

11. Jump up^ John McPhee, Basin and Range, pp.113-114.

12. Jump up^ Great Soviet Encyclopedia (in Russian) (3rd ed.), Moscow:

Sovetskaya Enciklopediya, 1974, vol. 16, p. 50

13. Jump up^ Rudwick, Martin Worlds Before Adam: The Reconstruction of

Geohistory in the Age of Reform (2008) pp. 539-545

14. Jump up^ Geologic Time Scale

 

15. Jump up^ How the discovery of geologic time changed our view of the

world

 

, Bristol University

16. Jump up^ Felix M. Gradstein, James G. Ogg, Alan G. Smith (Editors);A

Geologic Time Scale 2004, Cambridge University Press, 2005, (ISBN 0-

521-78673-8)

17. Jump up^ Cox, Simon J.D.; Richard, Stephen M. (2005). "A formal model

for the geologic time scale and global stratotype section and point,

compatible with geospatial information transfer standards"

 

. Geosphere (The Geological Society of America) 1 (3): 119–

137.doi:10.1130/GES00022.1

 

. Retrieved 31 December 2012.

18. Jump up^ International Commission on Stratigraphy. "International

Stratigraphic Chart"

 

. Retrieved 2009-09-25.

19. Jump up^ Paleontologists often refer to faunal stages rather than

geologic (geological) periods. The stage nomenclature is quite complex.

For an excellent time-ordered list of faunal stages, see "The Paleobiology

Database"

 

. Retrieved 2006-03-19.

20. ^ Jump up to:a b Dates are slightly uncertain with differences of a few

percent between various sources being common. This is largely due to

uncertainties in radiometric dating and the problem that deposits suitable

for radiometric dating seldom occur exactly at the places in the geologic

column where they would be most useful. The dates and errors quoted

above are according to the International Commission on Stratigraphy 2012

time scale. Where errors are not quoted, errors are less than the precision

of the age given. Dates labeled with a * indicate boundaries where aGlobal

Boundary Stratotype Section and Point has been internationally agreed

upon: see List of Global Boundary Stratotype Sections and Points for a

complete list.

21. Jump up^ References to the "Post-Cambrian Supereon" are not

universally accepted, and therefore must be considered unofficial.

22. Jump up^ Historically, the Cenozoic has been divided up into

theQuaternary and Tertiary sub-eras, as well as

the Neogeneand Paleogene periods. The 2009 version of the ICS time

chart

 

 recognizes a slightly extended Quaternary as well as the Paleogene and

a truncated Neogene, the Tertiary having been demoted to informal status.

23. Jump up^ "NASA Scientists React to 400 ppm Carbon Milestone".

Accessed 1/15/2014 [1]

 

24. ^ Jump up to:a b c d e f 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

 

.

25. ^ Jump up to:a b c d e f 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

atImage:Phanerozoic_Carbon_Dioxide.png, Image:65 Myr Climate

Change.png, Image:Five Myr Climate Change.png, respectively.

26. Jump up^ The start time for the Holocene epoch is here given

as11,700 years ago. For further discussion of the dating of this epoch,

see Holocene.

27. Jump up^ In North America, the Carboniferous is subdivided

intoMississippian and Pennsylvanian Periods.

28. Jump up^ The Precambrian is also known as Cryptozoic.

29. ^ Jump up to:a b c d e f g h i j k l m n The Proterozoic, Archean andHadean are

often collectively referred to as the Precambrian Time or sometimes, also

the Cryptozoic.

30. ^ Jump up to:a b c d e f g h i j k l Defined by absolute age (Global Standard

Stratigraphic Age).

31. Jump up^ The age of the oldest measurable craton, or continental crust,

is dated to 3600–3800 Ma

32. Jump up^ Though commonly used, the Hadean is not a formal eon and

no lower bound for the Archean and Eoarchean have been agreed upon.

The Hadean has also sometimes been called the Priscoan or the Azoic.

Sometimes, the Hadean can be found to be subdivided according to

the lunar geologic time scale. These eras include the Cryptic andBasin

Groups (which are subdivisions of the Pre-Nectarianera), Nectarian,

and Early Imbrian units.

33. ^ Jump up to:a b c d These unit names were taken from the Lunar geologic

timescale and refer to geologic events that did not occur on Earth. Their

use for Earth geology is unofficial. Note that their start times do not

dovetail perfectly with the later, terrestrially defined boundaries.

34. Jump up^ 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

 

. The oldest rock on Earth is the Acasta Gneiss, and it dates to 4.03 Ga,

located in the Northwest Territories of Canada.

35. Jump up^ Geology.wisc.edu

 

36. ^ Jump up to:a b c d e f g h i j k l m n 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 and Gabi M.

Ogg. The geologic time scale 2012 (1st ed. ed.). Amsterdam: Elsevier.

pp. 359–365. ISBN 978-0-44-459425-9.

37. ^ Jump up to:a b c Goldblatt, C.; K. J. Zahnle, N. H. Sleep, and E. G. Nisbet

(2010). "The Eons of Chaos and Hades"

 

.Solid Earth (Copernicus Publications on behalf of the European

Geosciences Union) 1: 1–3.

38. Jump up^ Chambers, John E. (July 2004). "Planetary accretion in the

inner Solar System"

 

. Earth and Planetary Science Letters 223 (3-4): 241–

252.doi:10.1016/j.epsl.2004.04.031

 

.

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, retrieved 18 November 2011

Gradstein, F.M & Ogg, J.G (2004), A Geologic Time scale 2004 - Why,

How and Where Next!

 

, retrieved 18 November

Gradstein, Felix M., Ogg, James G. & Smith, Alan G (2004), A Geologic

Time Scale 2004

 

, New York; Cambridge, UK: Cambridge University Press, ISBN 0-521-

78142-6, retrieved 18 November 2011 Paperback ISBN 0-521-78673-8

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, retrieved 18 November 2011

Knoll, Andrew H. , Walter, Malcolm R., Narbonne, Guy M., Christie-Blick,

Nicholas (30 July 2004), "A New Period for the Geologic Time Scale"

 

, Science 305 (5684): 621–622,doi:10.1126/science.1098803

 

, PMID 15286353

 

, 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

External links[edit]

NASA: Geologic Time

 

GSA: Geologic Time Scale

 

British Geological Survey: Geological Timechart

 

GeoWhen Database

 

International Commission on Stratigraphy Time Scale

 

Chronos.org

 

National Museum of Natural History - Geologic Time

 

SeeGrid: Geological Time Systems

 

 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

 

Deep Time - A History of the Earth   : Interactive Infographic

 

[show]

V

T

E

Geologic history of Earth

[show]

V

T

E

Time

[show]

V

T

E

Time measurement and standards

[show]

V

T

E

Chronology

[show]

V

T

E

Earth-related topics

Categories: 

Geologic time scale

Geology timelines

Geochronology

Geology-related lists

Geology terminology

Historical geology

Earth sciences

Navigation menu

Create account

Log in

Article

Talk

Read

Edit

View history

Main page

Contents

Featured content

Current events

Random article

Donate to Wikipedia

Interaction

Help

About Wikipedia

Community portal

Recent changes

Contact page

Tools

Print/export

Languages

Afrikaans

العربية Asturianu বাং��লা�

Беларуская

Brezhoneg

Català

Čeština

Cymraeg

Dansk

Deutsch

Eesti

Ελληνικά

Español

Esperanto

Euskara

فارسی Français

Gaeilge

Galego

한국어 हि�न्दी�

Hrvatski

Bahasa Indonesia

Interlingua

Íslenska

Italiano

עברית ಕನ್ನ�ಡ ქართული

Қазақша

Kreyòl ayisyen

Latgaļu

Latina

Latviešu

Lëtzebuergesch

Lietuvių

Magyar

Македонски

Bahasa Melayu

Монгол

Nederlands

日本語 Norsk bokmål

Norsk nynorsk

Polski

Português

Română

Русский

Саха тыла

Shqip

Simple English

Slovenčina

Slovenščina

Српски / srpski

Srpskohrvatski / српскохрватски

Suomi

Svenska ไทย Türkçe

Українська

اردو Vèneto

Tiếng Việt

Walon

文言

West-Vlams

吴 语

中文

Edit links

This page was last modified on 20 January 2014 at 06:19.

Text is available under the Creative Commons Attribution-ShareAlike License

; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. 

Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.

Privacy policy

About Wikipedia

Disclaimers

Contact Wikipedia

Developers

Mobile view