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The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current
Phanerozoic The Phanerozoic Eon is the current geologic eon in the geologic time scale The geologic time scale (GTS) is a system of chronological dating that classifies Geology, geological strata (stratigraphy) in time. It is used by geologists, paleontolo ...
Eon. The Precambrian is so named because it preceded the
Cambrian The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period A geological period is one of the several subdivisions of geologic time enabling cross-referencing of rocks and geologic events from place to place. These perio ...
, the first
period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Period, a descriptor for a historical or period drama ...
of the Phanerozoic Eon, which is named after
Cambria Cambria is a name for Wales, being the Latinised form of the Welsh language, Welsh name for the country, . The term was not in use during the Roman Britain, Roman period (when Wales had not come into existence as a distinct entity). It emerged lat ...

Cambria
, the Latinised name for
Wales Wales ( cy, Cymru ) is a country A country is a distinct territory, territorial body or political entity. It is often referred to as the land of an individual's birth, residence or citizenship. A country may be an independent sovereign ...

Wales
, where rocks from this age were first studied. The Precambrian accounts for 88% of the Earth's geologic time. The Precambrian is an informal unit of geologic time, subdivided into three eons (
Hadean The Hadean ( ) is a geologic eon of Earth history preceding the Archean. It began with the formation of the Earth about 4.6 billion years ago and ended, as defined by the International Commission on Stratigraphy The International Commissio ...

Hadean
,
Archean The Archean Eon ( , also spelled Archaean or Archæan) is one of the four geology, geologic eon (geology), eons of Earth, Earth's history, occurring (4 to 2.5 Billion years, Gya). During the Archean, the Earth's Crust (geology), crust had ...

Archean
,
Proterozoic The Proterozoic () is a geological eon spanning the time interval from 2500 to 541million years ago. It is the most recent part of the Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest par ...
) of the
geologic time scale The geologic time scale (GTS) is a system of chronological dating Chronological dating, or simply dating, is the process of attributing to an object or event a date in the past, allowing such object or event to be located in a previously establi ...

geologic time scale
. It spans from the formation of Earth about 4.6 billion years ago ( Ga) to the beginning of the Cambrian Period, about million years ago ( Ma), when hard-shelled creatures first appeared in abundance.


Overview

Relatively little is known about the Precambrian, despite it making up roughly seven-eighths of the Earth's history, and what is known has largely been discovered from the 1960s onwards. The Precambrian fossil record is poorer than that of the succeeding
Phanerozoic The Phanerozoic Eon is the current geologic eon in the geologic time scale The geologic time scale (GTS) is a system of chronological dating that classifies Geology, geological strata (stratigraphy) in time. It is used by geologists, paleontolo ...
, and fossils from the Precambrian (e.g.
stromatolites Stromatolites () or stromatoliths () are layered sedimentary formation of rocks, formations (microbialite) that are created mainly by photosynthetic microorganisms such as cyanobacteria, sulfate-reducing microorganism, sulfate-reducing bacteria ...

stromatolites
) are of limited
biostratigraphic Biostratigraphy is the branch of stratigraphy through Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic period million years ago (Year, Mya ...
use. This is because many Precambrian rocks have been heavily
metamorphosed Metamorphic rocks arise from the transformation of existing rock Rock most often refers to: * Rock (geology) A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the mineral ...

metamorphosed
, obscuring their origins, while others have been destroyed by erosion, or remain deeply buried beneath Phanerozoic strata. It is thought that the Earth coalesced from material in orbit around the Sun at roughly 4,543 Ma, and may have been struck by another planet called
Theia In Greek mythology Greek mythology is the body of s originally told by the , and a of . These stories concern the and , the lives and activities of , , and , and the origins and significance of the ancient Greeks' own and practices. Mo ...
shortly after it formed, splitting off material that formed the
Moon The Moon is Earth's only natural satellite. At about one-quarter the diameter of Earth (comparable to the width of Australia (continent), Australia), it is the largest natural satellite in the Solar System relative to the size of its plane ...

Moon
(see
Giant impact hypothesis The giant-impact hypothesis, sometimes called the Big Splash, or the Theia Impact, suggests that the Moon The Moon is Earth's only proper natural satellite. At one-quarter the diameter of Earth (comparable to the width of Australia ...
). A stable crust was apparently in place by 4,433 Ma, since
zircon Zircon ( or ) is a mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in ...

zircon
crystals from
Western Australia Western Australia (abbreviated as WA) is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspape ...

Western Australia
have been
dated Date or dates may refer to: *Date (fruit), the fruit of the date palm (''Phoenix dactylifera'') Social activity *Dating, a form of courtship involving social activity, with the aim of assessing a potential partner **Group date, wherein a group ...
at 4,404 ± 8 Ma. The term "Precambrian" is used by
geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, although backgrounds in physics, chem ...

geologist
s and
paleontologists Paleontology, also spelled palaeontology or palæontology (), is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene The Holocene ( ) is the current geological epoch. It began approximate ...
for general discussions not requiring a more specific eon name. However, both the
United States Geological Survey The United States Geological Survey, abbreviated USGS and formerly simply known as the Geological Survey, is a scientific government agency, agency of the Federal government of the United States, United States government. The scientists of the ...
and the
International Commission on Stratigraphy The International Commission on Stratigraphy (ICS), sometimes referred to unofficially as the "International Stratigraphic Commission", is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigr ...
regard the term as informal. Because the span of time falling under the Precambrian consists of three eons (the
Hadean The Hadean ( ) is a geologic eon of Earth history preceding the Archean. It began with the formation of the Earth about 4.6 billion years ago and ended, as defined by the International Commission on Stratigraphy The International Commissio ...

Hadean
, the
Archean The Archean Eon ( , also spelled Archaean or Archæan) is one of the four geology, geologic eon (geology), eons of Earth, Earth's history, occurring (4 to 2.5 Billion years, Gya). During the Archean, the Earth's Crust (geology), crust had ...

Archean
, and the
Proterozoic The Proterozoic () is a geological eon spanning the time interval from 2500 to 541million years ago. It is the most recent part of the Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest par ...
), it is sometimes described as a ''supereon'', but this is also an informal term, not defined by the ICS in its chronostratigraphic guide. ' (from “earliest”) was a synonym for ''pre-Cambrian'', or more specifically ''
Archean The Archean Eon ( , also spelled Archaean or Archæan) is one of the four geology, geologic eon (geology), eons of Earth, Earth's history, occurring (4 to 2.5 Billion years, Gya). During the Archean, the Earth's Crust (geology), crust had ...

Archean
''.


Life forms

A specific date for the origin of life has not been determined.
Carbon Carbon (from la, carbo "coal") is a with the C and 6. It is lic and —making four s available to form s. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three occur naturally, ...

Carbon
found in 3.8 billion-year-old rocks (Archean Eon) from islands off western
Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an autonomous territory An autonomous administrative division (also referred to as an autonomous area, entity, unit, region, subdivision, or territory) is a subnational administra ...

Greenland
may be of organic origin. Well-preserved microscopic fossils of
bacteria Bacteria (; common noun bacteria, singular bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typ ...

bacteria
older than 3.46 billion years have been found in
Western Australia Western Australia (abbreviated as WA) is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspape ...

Western Australia
. Probable fossils 100 million years older have been found in the same area. However, there is evidence that life could have evolved over 4.280 billion years ago. There is a fairly solid record of bacterial life throughout the remainder (Proterozoic Eon) of the Precambrian. Complex multicellular organisms may have appeared as early as 2100 Ma. However, the interpretation of ancient fossils is problematic, and "... some definitions of multicellularity encompass everything from simple bacterial colonies to badgers." Other possible early complex multicellular organisms include a possible 2450 Ma red alga from the Kola Peninsula, 1650 Ma carbonaceous biosignatures in north China, the 1600 Ma '' Rafatazmia'', and a possible 1047 Ma '' Bangiomorpha'' red alga from the Canadian Arctic. The earliest fossils widely accepted as complex multicellular organisms date from the Ediacaran Period. A very diverse collection of soft-bodied forms is found in a variety of locations worldwide and date to between 635 and 542 Ma. These are referred to as Ediacaran or Vendian biota. Hard-shelled creatures appeared toward the end of that time span, marking the beginning of the Phanerozoic Eon. By the middle of the following Cambrian Period, a very diverse fauna is recorded in the
Burgess Shale The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At old (Wuliuan, middle Cambrian), it is one of the earl ...
, including some which may represent stem groups of modern taxa. The increase in diversity of lifeforms during the early Cambrian is called the Cambrian explosion of life. While land seems to have been devoid of plants and animals, cyanobacteria and other microbes formed prokaryotic
mats Mats is a given name, a Scandinavian and Estonian form of Matthew (given name), Matthew or Matthias, and may refer to: * Mats Bergman (born 1948), Swedish actor * Mats Eilertsen (born 1975), Norwegian jazz musician and composer * Mats Engman (born ...
that covered terrestrial areas. Tracks from an animal with leg-like appendages have been found in what was mud 551 million years ago.


Planetary environment and the oxygen catastrophe

Evidence of the details of plate motions and other
tectonic Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building A mountain is an elevated portion of the Earth's crust, gen ...
activity in the Precambrian has been poorly preserved. It is generally believed that small proto-continents existed prior to 4280 Ma, and that most of the Earth's landmasses collected into a single
supercontinent In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid Earth, the rock (geology), rocks of which it is composed, and the proces ...
around 1130 Ma. The supercontinent, known as
Rodinia Rodinia (from the Russian родить, ''rodit'', meaning "to beget, to give birth", or родина, ''rodina'', meaning "motherland, birthplace") was a Neoproterozoic supercontinent that assembled 1.1–0.9 billion years ago and broke up 750 ...

Rodinia
, broke up around 750 Ma. A number of
glacial periods A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier A glacier ( or ) is a persistent body of dense ice that is constantly movi ...
have been identified going as far back as the
Huronian The Huronian glaciation (or Makganyene glaciation) was a glaciation that extended from 2.4 billion years ago (Gya) to 2.1 Gya, during the Siderian and Rhyacian periods of the Paleoproterozoic era. The Huronian glaciation followed the Great Oxyge ...
epoch, roughly 2400–2100 Ma. One of the best studied is the
Sturtian-Varangian The Cryogenian (, from Greek language, Greek κρύος ''(krýos)'', meaning "cold" and γένεσις ''(génesis)'', meaning "birth") is a geologic period that lasted from . It forms the second geologic period of the Neoproterozoic era (geology ...
glaciation, around 850–635 Ma, which may have brought glacial conditions all the way to the equator, resulting in a "
Snowball Earth The Snowball Earth hypothesis proposes that, during one or more of Earth's Greenhouse and icehouse Earth, icehouse climates, the Earth's surface, planet's surface became entirely or nearly entirely frozen. It is believed that this occurred someti ...
". The
atmosphere An atmosphere (from the greek words ἀτμός ''(atmos)'', meaning 'vapour', and σφαῖρα ''(sphaira)'', meaning 'ball' or 'sphere') is a layer or a set of layers of gases surrounding a planet or other material body, that is held in ...

atmosphere
of the early Earth is not well understood. Most geologists believe it was composed primarily of nitrogen, carbon dioxide, and other relatively inert gases, and was lacking in free
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

oxygen
. There is, however, evidence that an oxygen-rich atmosphere existed since the early Archean. At present, it is still believed that
molecular A scanning tunneling microscopy image of pentacene molecules, which consist of linear chains of five carbon rings. A molecule is an electrically neutral group of two or more atom An atom is the smallest unit of ordinary matter In ...
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

oxygen
was not a significant fraction of Earth's atmosphere until after
photosynthetic Photosynthesis is a process used by plants and other organisms to convert Conversion or convert may refer to: Arts, entertainment, and media * Conversion (Doctor Who audio), "Conversion" (''Doctor Who'' audio), an episode of the audio drama ' ...

photosynthetic
life forms evolved and began to produce it in large quantities as a byproduct of their metabolism. This radical shift from a chemically inert to an oxidizing atmosphere caused an
ecological crisis An ecological crisis occurs when changes to the environment Environment most often refers to: __NOTOC__ * Natural environment, all living and non-living things occurring naturally * Biophysical environment, the physical and biological factors alo ...
, sometimes called the oxygen catastrophe. At first, oxygen would have quickly combined with other elements in Earth's crust, primarily iron, removing it from the atmosphere. After the supply of oxidizable surfaces ran out, oxygen would have begun to accumulate in the atmosphere, and the modern high-oxygen atmosphere would have developed. Evidence for this lies in older rocks that contain massive
banded iron formation Banded iron formations (also known as banded ironstone formations or BIFs) are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. They can be up to several hundred meters in thickness a ...

banded iron formation
s that were laid down as iron oxides.


Subdivisions

A terminology has evolved covering the early years of the Earth's existence, as
radiometric dating Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "di ...
has allowed absolute dates to be assigned to specific formations and features. The Precambrian is divided into three eons: the
Hadean The Hadean ( ) is a geologic eon of Earth history preceding the Archean. It began with the formation of the Earth about 4.6 billion years ago and ended, as defined by the International Commission on Stratigraphy The International Commissio ...

Hadean
(– Ma),
Archean The Archean Eon ( , also spelled Archaean or Archæan) is one of the four geology, geologic eon (geology), eons of Earth, Earth's history, occurring (4 to 2.5 Billion years, Gya). During the Archean, the Earth's Crust (geology), crust had ...

Archean
(- Ma) and
Proterozoic The Proterozoic () is a geological eon spanning the time interval from 2500 to 541million years ago. It is the most recent part of the Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest par ...
(- Ma). See Timetable of the Precambrian. *
Proterozoic The Proterozoic () is a geological eon spanning the time interval from 2500 to 541million years ago. It is the most recent part of the Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest par ...
: this eon refers to the time from the lower
Cambrian The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period A geological period is one of the several subdivisions of geologic time enabling cross-referencing of rocks and geologic events from place to place. These perio ...
boundary, Ma, back through Ma. As originally used, it was a synonym for "Precambrian" and hence included everything prior to the Cambrian boundary. The Proterozoic Eon is divided into three eras: the
Neoproterozoic The Neoproterozoic Era is the unit of geologic time The geologic time scale (GTS) is a system of chronological datingChronological dating, or simply dating, is the process of attributing to an object or event a date in the past, allowing such ob ...
,
Mesoproterozoic The Mesoproterozoic Era is a geology, geologic era (geology), era that occurred from . The Mesoproterozoic was the first period of Earth's history of which a fairly definitive geological record survives. Continents existed during the preceding era ...
and
Paleoproterozoic The Paleoproterozoic Era (;, also spelled Palaeoproterozoic), spanning the time period from (2.5–1.6 Year, Ga), is the first of the three sub-divisions (era (geology), eras) of the Proterozoic Eon. The Paleoproterozoic is also the longest ...
. **
Neoproterozoic The Neoproterozoic Era is the unit of geologic time The geologic time scale (GTS) is a system of chronological datingChronological dating, or simply dating, is the process of attributing to an object or event a date in the past, allowing such ob ...
: The youngest
geologic eraA geologic era is a subdivision of geologic time that divides an Eon (geology), eon into smaller units of time. The Phanerozoic, Phanerozoic Eon is divided into three such time frames: the Paleozoic, Mesozoic, and Cenozoic (meaning "old life", "middl ...
of the Proterozoic Eon, from the
Cambrian The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period A geological period is one of the several subdivisions of geologic time enabling cross-referencing of rocks and geologic events from place to place. These perio ...
Period lower boundary ( Ma) back to Ma. The Neoproterozoic corresponds to Precambrian Z rocks of older North American stratigraphy. ***
Ediacaran The Ediacaran Period ( ) is a geological period A geological period is one of the several subdivisions of geologic time enabling cross-referencing of rocks and geologic events from place to place. These periods form elements of a hierarchy of ...
: The youngest
geologic period The geologic time scale (GTS) is a system of chronological dating that classifies Geology, geological strata (stratigraphy) in time. It is used by geologists, paleontology, paleontologists, and other earth sciences, Earth scientists to describe t ...
within the Neoproterozoic Era. The "2012 Geologic Time Scale" dates it from to Ma. In this period the Ediacaran fauna appeared. ***
Cryogenian The Cryogenian (, from grc, κρύος, krýos, meaning "cold" and , romanized: , meaning "birth") is a geologic period that lasted from . It forms the second geologic period of the Neoproterozoic era (geology), Era, preceded by the Tonian Perio ...
: The middle period in the
Neoproterozoic The Neoproterozoic Era is the unit of geologic time The geologic time scale (GTS) is a system of chronological datingChronological dating, or simply dating, is the process of attributing to an object or event a date in the past, allowing such ob ...
Era: - Ma. ***
Tonian The Tonian (from grc, τόνος, tónos, meaning "stretch") is the first geologic period The geologic time scale (GTS) is a system of chronological dating that classifies Geology, geological strata (stratigraphy) in time. It is used by geolo ...
: the earliest period of the Neoproterozoic Era: - Ma. **
Mesoproterozoic The Mesoproterozoic Era is a geology, geologic era (geology), era that occurred from . The Mesoproterozoic was the first period of Earth's history of which a fairly definitive geological record survives. Continents existed during the preceding era ...
: the middle era of the
Proterozoic The Proterozoic () is a geological eon spanning the time interval from 2500 to 541million years ago. It is the most recent part of the Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest par ...
Eon, - Ma. Corresponds to "Precambrian Y" rocks of older North American stratigraphy. **
Paleoproterozoic The Paleoproterozoic Era (;, also spelled Palaeoproterozoic), spanning the time period from (2.5–1.6 Year, Ga), is the first of the three sub-divisions (era (geology), eras) of the Proterozoic Eon. The Paleoproterozoic is also the longest ...
: oldest era of the Proterozoic Eon, - Ma. Corresponds to "Precambrian X" rocks of older North American stratigraphy. *
Archean The Archean Eon ( , also spelled Archaean or Archæan) is one of the four geology, geologic eon (geology), eons of Earth, Earth's history, occurring (4 to 2.5 Billion years, Gya). During the Archean, the Earth's Crust (geology), crust had ...

Archean
Eon: - Ma. *
Hadean The Hadean ( ) is a geologic eon of Earth history preceding the Archean. It began with the formation of the Earth about 4.6 billion years ago and ended, as defined by the International Commission on Stratigraphy The International Commissio ...

Hadean
Eon: – Ma. This term was intended originally to cover the time before any preserved rocks were deposited, although some
zircon Zircon ( or ) is a mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in ...

zircon
crystals from about 4400 Ma demonstrate the existence of crust in the Hadean Eon. Other records from Hadean time come from the
moon The Moon is Earth's only natural satellite. At about one-quarter the diameter of Earth (comparable to the width of Australia (continent), Australia), it is the largest natural satellite in the Solar System relative to the size of its plane ...
and
meteorite A meteorite is a solid piece of debris from an object, such as a comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces ...
s. It has been proposed that the Precambrian should be divided into eons and eras that reflect stages of planetary evolution, rather than the current scheme based upon numerical ages. Such a system could rely on events in the stratigraphic record and be demarcated by GSSPs. The Precambrian could be divided into five "natural" eons, characterized as follows: # Accretion and differentiation: a period of planetary formation until giant Moon-forming impact event. # Hadean: dominated by heavy bombardment from about 4.51 Ga (possibly including a Cool Early Earth period) to the end of the
Late Heavy Bombardment The Late Heavy Bombardment (LHB), or lunar cataclysm, is a hypothesized event thought to have occurred approximately 4.1 to 3.8 billion year A year is the orbital period The orbital period is the time a given astronomical object takes ...
period. # Archean: a period defined by the first crustal formations (the Isua greenstone belt) until the deposition of
banded iron formation Banded iron formations (also known as banded ironstone formations or BIFs) are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. They can be up to several hundred meters in thickness a ...

banded iron formation
s due to increasing atmospheric oxygen content. # Transition: a period of continued iron banded formation until the first continental
red beds Red beds (or redbeds) are sedimentary rocks, typically consisting of sandstone Sandstone is a clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains. Sandstones make up abou ...
. # Proterozoic: a period of modern
plate tectonics upright=1.35, Diagram of the internal layering of Earth showing the lithosphere above the asthenosphere (not to scale) Plate tectonics (from the la, label=Late Latin Late Latin ( la, Latinitas serior) is the scholarly name for the written L ...
until the first
animal Animals (also called Metazoa) are multicellular A multicellular organism is an organism In biology, an organism () is any organic, life, living system that functions as an individual entity. All organisms are composed of cells ...

animal
s.


Precambrian supercontinents

The movement of Earth's plates has caused the formation and break-up of continents over time, including occasional formation of a
supercontinent In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid Earth, the rock (geology), rocks of which it is composed, and the proces ...
containing most or all of the landmass. The earliest known supercontinent was
Vaalbara Vaalbara was an Archean supercontinent In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid Earth, the rock (geology), rock ...
. It formed from proto-continents and was a supercontinent 3.636 billion years ago.
Vaalbara Vaalbara was an Archean supercontinent In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid Earth, the rock (geology), rock ...
broke up c. 2.845–2.803 Ga ago. The supercontinent was formed c. 2.72 Ga ago and then broke sometime after 2.45–2.1 Ga into the proto-continent
craton A craton (, , or ; from el, κράτος ''kratos'' "strength") is an old and stable part of the continental lithosphere A lithosphere ( grc, λίθος [] for "rocky", and [] for "sphere") is the rigid, outermost shell of a terrestrial p ...
s called Laurentia, Baltica, Yilgarn craton and Kalahari Craton, Kalahari. The supercontinent
Columbia Columbia may refer to: * Columbia (personification), the historical female national personification of the United States, and a poetic name for the Americas Places North America Natural features * Columbia Plateau, a geologic and geographic regio ...
, or Nuna, formed 2.1–1.8 billion years ago and broke up about 1.3–1.2 billion years ago. The supercontinent
Rodinia Rodinia (from the Russian родить, ''rodit'', meaning "to beget, to give birth", or родина, ''rodina'', meaning "motherland, birthplace") was a Neoproterozoic supercontinent that assembled 1.1–0.9 billion years ago and broke up 750 ...

Rodinia
is thought to have formed about 1300-900 Ma, to have embodied most or all of Earth's continents and to have broken up into eight continents around 750–600 million years ago.


See also

* ** ** **


References


Further reading

* Valley, John W., William H. Peck, Elizabeth M. King (1999) ''Zircons Are Forever'', The Outcrop for 1999, University of Wisconsin-Madiso
Wgeology.wisc.edu
– ''Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago'' Accessed Jan. 10, 2006 * *


External links



from the Paleomap Project {{Authority control