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The Neogene ( ) (informally Upper Tertiary or Late Tertiary) is a
geologic period and system
geologic period and system
that spans 20.45 million years from the end of the
Paleogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous The Cretaceous ( ) is a geological period A geologi ...
Period million years ago ( Mya) to the beginning of the present
Quaternary The Quaternary ( ) is the current and most recent of the three period (geology), periods of the Cenozoic era (geology), Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans ...
Period Mya. The Neogene is sub-divided into two
epoch In chronology 222px, Joseph Scaliger's ''De emendatione temporum'' (1583) began the modern science of chronology Chronology (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-E ...
s, the earlier
Miocene The Miocene ( ) is the first geological epoch In geochronology, an epoch is a subdivision of the geologic timescale that is longer than an age (geology), age but shorter than a period (geology), period. The current epoch is the Holocene Epoch of ...
and the later
Pliocene The Pliocene ( ; also Pleiocene) epoch (geology), Epoch is the epoch in the geologic timescale that extends from 5.333 million to 2.58Quaternary The Quaternary ( ) is the current and most recent of the three period (geology), periods of the Cenozoic era (geology), Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans ...
. The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes (1815–1868). During this period,
mammal Mammals (from Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Communication (from Latin ''communicare'', meaning "to share" or "to be i ...
s and
bird Birds are a group of warm-blooded vertebrate Vertebrates () comprise all species of animal Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biology), biological kingdom Animalia. With ...

bird
s continued to evolve into modern forms, while other groups of life remained relatively unchanged. The first humans (''
Homo habilis ''Homo habilis'' ("handy man") is a species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the large ...

Homo habilis
'') appeared in Africa near the end of the period. Some continental movement took place, the most significant event being the connection of
North North is one of the four compass points The points of the compass are the vectors by which planet A planet is an astronomical body orbiting a star or Stellar evolution#Stellar remnants, stellar remnant that is massive enough to be Hydro ...

North
and
South America South America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continent ...

South America
at the
Isthmus of Panama The Isthmus of Panama ( es, Istmo de Panamá), also historically known as the Isthmus of Darien (), is the narrow strip of land that lies between the Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lamè Kara ...
, late in the Pliocene. This cut off the warm ocean currents from the Pacific to the Atlantic Ocean, leaving only the
Gulf Stream The Gulf Stream, together with its northern extension the North Atlantic Drift The North Atlantic Current (NAC), also known as North Atlantic Drift and North Atlantic Sea Movement, is a powerful warm western boundary current Boundary curren ...
to transfer heat to the
Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five major s. It spans an area of approximately and is also known as the coldest of all the oceans. The (IHO) recognizes it as an ocean, although some call it the Arctic Medit ...

Arctic Ocean
. The global climate cooled considerably over the course of the Neogene, culminating in a series of continental glaciations in the
Quaternary The Quaternary ( ) is the current and most recent of the three period (geology), periods of the Cenozoic era (geology), Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans ...
Period that follows.


Divisions

In ICS terminology, from upper (later, more recent) to lower (earlier): The
Pliocene The Pliocene ( ; also Pleiocene) epoch (geology), Epoch is the epoch in the geologic timescale that extends from 5.333 million to 2.58Piacenzian The Piacenzian is in the international geologic time scale the upper stage (stratigraphy), stage or latest age (geology), age of the Pliocene. It spans the time between 3.6 ± 0.005 annum, Ma and 2.588 ± 0.005 Ma (million years ago). The Piacenzian ...
Age, preceded by *
Zanclean The Zanclean is the lowest stage (stratigraphy), stage or earliest age (geology), age on the geologic time scale of the Pliocene. It spans the time between 5.332 ± 0.005 annum, Ma (million years ago) and 3.6 ± 0.005 Ma. It is preceded by the Me ...
Age The
Miocene The Miocene ( ) is the first geological epoch In geochronology, an epoch is a subdivision of the geologic timescale that is longer than an age (geology), age but shorter than a period (geology), period. The current epoch is the Holocene Epoch of ...
Epoch is subdivided into six ages: *
Messinian The Messinian is in the geologic timescale 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 object or ...
Age, preceded by *
Tortonian The Tortonian is in 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 ...
Age *
Serravallian The Serravallian is in the geologic timescale 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 ...
Age *
Langhian The Langhian is, in the ICS geologic timescale 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 oth ...
Age *
Burdigalian The Burdigalian is, in the geologic timescale 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 object ...
Age * Aquitanian Age In different geophysical regions of the world, other regional names are also used for the same or overlapping ages and other timeline subdivisions. The terms ''Neogene System'' (formal) and ''Upper Tertiary System'' (informal) describe the rocks deposited during the ''Neogene Period''.


Geography

The continents in the Neogene were very close to their current positions. The
Isthmus of Panama The Isthmus of Panama ( es, Istmo de Panamá), also historically known as the Isthmus of Darien (), is the narrow strip of land that lies between the Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lamè Kara ...
formed, connecting
North North is one of the four compass points The points of the compass are the vectors by which planet A planet is an astronomical body orbiting a star or Stellar evolution#Stellar remnants, stellar remnant that is massive enough to be Hydro ...

North
and
South America South America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continent ...

South America
. The Indian subcontinent continued to collide with
Asia Asia () is Earth's largest and most populous continent, located primarily in the Eastern Hemisphere, Eastern and Northern Hemisphere, Northern Hemisphere of the Earth, Hemispheres. It shares the continental landmass of Eurasia with the cont ...

Asia
, forming the
Himalayas The Himalayas, or Himalaya (; Sanskrit Sanskrit (; attributively , ; nominalization, nominally , , ) is a classical language of South Asia that belongs to the Indo-Aryan languages, Indo-Aryan branch of the Indo-European languages. It ar ...

Himalayas
. Sea levels fell, creating
land bridge In biogeography Biogeography is the study of the distribution of species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A sp ...
s between
Africa Africa is the world's second-largest and second-most populous continent A continent is any of several large landmass A landmass, or land mass, is a large region In geography Geography (from Greek: , ''geographia'', ...

Africa
and
Eurasia Eurasia () is the largest continent A continent is any of several large landmass A landmass, or land mass, is a large region In geography Geography (from Greek: , ''geographia'', literally "earth description") is a ...

Eurasia
and between Eurasia and North America.


Climate

The global climate became seasonal and continued an overall drying and cooling trend which began at the start of the
Paleogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous The Cretaceous ( ) is a geological period A geologi ...
. The ice caps on both poles began to grow and thicken, and by the end of the period the first of a series of glaciations of the current Ice Age began.


Flora and fauna

Marine and continental flora and fauna have a modern appearance. The reptile group
Choristodera Choristodera is an extinct Order (biology), order of list of semiaquatic tetrapods, semiaquatic diapsid reptiles that ranged from the Middle Jurassic, or possibly Triassic, to the late Miocene (168 to 11.6 million years ago). Choristoderes are mor ...
became extinct in the early part of the period, while the amphibians known as Allocaudata disappeared at the end.
Mammal Mammals (from Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Communication (from Latin ''communicare'', meaning "to share" or "to be i ...
s and
bird Birds are a group of warm-blooded vertebrate Vertebrates () comprise all species of animal Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biology), biological kingdom Animalia. With ...

bird
s continued to be the dominant terrestrial vertebrates, and took many forms as they adapted to various habitats. The first
hominin The Hominini form a taxonomic tribe of the subfamily Homininae Homininae (), also called "African hominids" or "African apes", is a subfamily of Hominidae The Hominidae (), whose members are known as great apes or hominids (), are a t ...

hominin
s, the ancestors of humans may have appeared in southern Europe and migrated into Africa. The first humans (belonging to the species ''
Homo habilis ''Homo habilis'' ("handy man") is a species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the large ...

Homo habilis
'') appeared in Africa near the end of the period. In response to the cooler, seasonal climate, tropical plant species gave way to
deciduous In the fields of horticulture Horticulture is the art of cultivating plants in gardens to produce food and medicinal ingredients, or for comfort and ornamental purposes. Horticulturists are agriculturists who grow flowers, fruits and nuts, ...
ones and grasslands replaced many forests. Grasses therefore greatly diversified, and herbivorous mammals evolved alongside it, creating the many grazing animals of today such as
horse The horse (''Equus ferus caballus'') is a domesticated Domestication is a sustained multi-generational relationship in which one group of organisms assumes a significant degree of influence over the reproduction and care of another group to ...

horse
s,
antelope The term antelope is used to refer to many species of even-toed ruminant Ruminants (suborder In biological classification, the order ( la, wikt:ordo#Latin, ordo) is # a taxonomic rank used in the classification of organisms and recognized by ...

antelope
, and
bison Bison are large, even-toed ungulate The even-toed ungulates (Artiodactyla , ) are ungulate Ungulates ( ) are members of the diverse clade A clade (; from grc, , ''klados'', "branch"), also known as a monophyletic group or natural gro ...

bison
.
Eucalyptus ''Eucalyptus'' () is a of over seven hundred species of s, shrubs or in the , Myrtaceae. Along with several other genera in the , including ', they are commonly known as s. Plants in the genus ''Eucalyptus'' have bark that is either smooth, ...

Eucalyptus
fossil leaves occur in the
Miocene The Miocene ( ) is the first geological epoch In geochronology, an epoch is a subdivision of the geologic timescale that is longer than an age (geology), age but shorter than a period (geology), period. The current epoch is the Holocene Epoch of ...
of New Zealand, where the genus is not native today, but have been introduced from Australia.


Disagreements

The Neogene traditionally ended at the end of the Pliocene Epoch, just before the older definition of the beginning of the
Quaternary The Quaternary ( ) is the current and most recent of the three period (geology), periods of the Cenozoic era (geology), Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans ...
Period; many time scales show this division. However, there was a movement amongst geologists (particularly
marine geologist Marine geology or geological oceanography is the study of the history and structure of the ocean floor. It involves geophysical, geochemistry, geochemical, sedimentology, sedimentological and paleontological investigations of the ocean floor and ...
s) to also include ongoing geological time (Quaternary) in the Neogene, while others (particularly terrestrial geologists) insist the Quaternary to be a separate period of distinctly different record. The somewhat confusing terminology and disagreement amongst geologists on where to draw what hierarchical boundaries is due to the comparatively fine divisibility of time units as time approaches the present, and due to geological preservation that causes the youngest sedimentary geological record to be preserved over a much larger area and to reflect many more environments than the older geological record. By dividing the
Cenozoic The Cenozoic ( ; ) is Earth's current geological era An era is a span of time defined for the purposes of chronology or historiography, as in the regnal eras in the history of a given monarchy, a calendar era used for a given calendar, or the ge ...

Cenozoic
Era into three (arguably two) periods (
Paleogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous The Cretaceous ( ) is a geological period A geologi ...
, Neogene,
Quaternary The Quaternary ( ) is the current and most recent of the three period (geology), periods of the Cenozoic era (geology), Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans ...
) instead of seven epochs, the periods are more closely comparable to the duration of periods in the Mesozoic and Paleozoic Eras. 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 ...
(ICS) once proposed that the Quaternary be considered a sub-era (sub-erathem) of the Neogene, with a beginning date of 2.58 Ma, namely the start of the Gelasian Stage. In the 2004 proposal of the ICS, the Neogene would have consisted of the
Miocene The Miocene ( ) is the first geological epoch In geochronology, an epoch is a subdivision of the geologic timescale that is longer than an age (geology), age but shorter than a period (geology), period. The current epoch is the Holocene Epoch of ...
and
Pliocene The Pliocene ( ; also Pleiocene) epoch (geology), Epoch is the epoch in the geologic timescale that extends from 5.333 million to 2.58International Union for Quaternary Research The International Union for Quaternary Research (INQUA) was founded in 1928. It has members from a number of scientific disciplines who study the environmental A biophysical environment is a life, biotic and Abiotic component, abiotic surroun ...
(INQUA) counterproposed that the Neogene and the Pliocene end at 2.58 Ma, that the Gelasian be transferred to the Pleistocene, and the Quaternary be recognized as the third period in the Cenozoic, citing key changes in Earth's climate, oceans, and biota that occurred 2.58 Ma and its correspondence to the Gauss-Matuyama magnetostratigraphic boundary.Clague, John ''et al.'' (2006) "Open Letter by INQUA Executive Committee"
''Quaternary Perspective, the INQUA Newsletter'' International Union for Quaternary Research 16(1)
In 2006 ICS and INQUA reached a compromise that made Quaternary a subera, subdividing Cenozoic into the old classical Tertiary and Quaternary, a compromise that was rejected by
International Union of Geological Sciences The International Union of Geological Sciences (IUGS) is an international non-governmental organization A non-governmental organization, or simply an NGO, is an that is, generally, formed independent from . They are typically s, and many o ...
because it split both Neogene and Pliocene in two. Following formal discussions at the 2008 International Geological Congress in Oslo, Norway, the ICS decided in May 2009 to make the Quaternary the youngest period of the Cenozoic Era with its base at 2.58 Mya and including the Gelasian Age, which was formerly considered part of the Neogene Period and Pliocene Epoch. Thus the Neogene Period ends bounding the succeeding Quaternary Period at 2.58 Mya.


References


External links

* {{Authority control Geological periods