Pliocene
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Pliocene | |
---|---|
Epoch | |
Stratigraphic unit | Series |
Time span formality | Formal |
Lower boundary definition | Base of the Thvera magnetic event (C3n.4n), which is only 96 ka (5 precession cycles) younger than the GSSP |
Lower boundary GSSP | Heraclea Minoa section, Heraclea Minoa, Cattolica Eraclea, Sicily, Italy 37°23′30″N 13°16′50″E / 37.3917°N 13.2806°E |
Lower GSSP ratified | 2000[4] |
Upper boundary definition |
|
Upper boundary GSSP | Monte San Nicola Section, Gela, Sicily, Italy 37°08′49″N 14°12′13″E / 37.1469°N 14.2035°E |
Upper GSSP ratified | 2009 (as base of Quaternary and Pleistocene)[5] |
Part of a series on |
Human history and prehistory |
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↑ before Homo (Pliocene epoch) |
↓ Future (Holocene epoch) |
The Pliocene (
As with other older geologic periods, the geological strata that define the start and end are well-identified but the exact dates of the start and end of the epoch are slightly uncertain. The boundaries defining the Pliocene are not set at an easily identified worldwide event but rather at regional boundaries between the warmer Miocene and the relatively cooler Pleistocene. The upper boundary was set at the start of the Pleistocene glaciations.
Etymology
Charles Lyell (later Sir Charles) gave the Pliocene its name in Principles of Geology (volume 3, 1833).[11]
The word pliocene comes from the Greek words πλεῖον (pleion, "more") and καινός (kainos, "new" or "recent")
Subdivisions

In the official timescale of the ICS, the Pliocene is subdivided into two stages. From youngest to oldest they are:
- Piacenzian (3.60–2.58 Ma)[13]
- Zanclean (5.33–3.60 Ma)[4]
The Piacenzian is sometimes referred to as the Late Pliocene, whereas the Zanclean is referred to as the Early Pliocene.
In the system of
- North American Land Mammal Ages (NALMA) include Hemphillian (9–4.75 Ma),[14][15] and Blancan (4.75–1.6 Ma).[16] The Blancan extends forward into the Pleistocene.
- South American Land Mammal Ages (SALMA) include Montehermosan (6.8–4.0 Ma), Chapadmalalan (4.0–3.0 Ma) and Uquian (3.0–1.2 Ma).[17]
In the Paratethys area (central Europe and parts of western Asia) the Pliocene contains the Dacian (roughly equal to the Zanclean) and Romanian (roughly equal to the Piacenzian and Gelasian together) stages. As usual in stratigraphy, there are many other regional and local subdivisions in use.
In
Climate

During the Pliocene epoch (5.3 to 2.6 million years ago (Ma)), the Earth's climate became cooler and drier, as well as more seasonal, marking a transition between the relatively warm Miocene to the cooler Pleistocene.[19] However, the beginning of the Pliocene was marked by an increase in global temperatures relative to the cooler Messinian. This increase was related to the 1.2 million year obliquity amplitude modulation cycle.[20] By 3.3-3.0 Ma, during the Mid-Piacenzian Warm Period (mPWP), global average temperature was 2–3 °C higher than today,[21] while carbon dioxide levels were the same as today (400 ppm).[22] Global sea level was about 25 m higher,[23] though its exact value is uncertain.[24][25] The northern hemisphere ice sheet was ephemeral before the onset of extensive glaciation over Greenland that occurred in the late Pliocene around 3 Ma.[26] The formation of an Arctic
During the Pliocene the earth climate system response shifted from a period of high frequency-low amplitude oscillation dominated by the 41,000-year period of Earth's obliquity to one of low-frequency, high-amplitude oscillation dominated by the 100,000-year period of the orbital eccentricity characteristic of the Pleistocene glacial-interglacial cycles.[29]
During the late Pliocene and early Pleistocene, 3.6 to 2.6 Ma, the Arctic was much warmer than it is at the present day (with summer temperatures some 8 °C warmer than today). That is a key finding of research into a lake-sediment core obtained in Eastern Siberia, which is of exceptional importance because it has provided the longest continuous late Cenozoic land-based sedimentary record thus far.[30]
During the late Zanclean, Italy remained relatively warm and humid.[31] Central Asia became more seasonal during the Pliocene, with colder, drier winters and wetter summers, which contributed to an increase in the abundance of C4 plants across the region.[32] In the Loess Plateau, δ13C values of occluded organic matter increased by 2.5% while those of pedogenic carbonate increased by 5% over the course of the Late Miocene and Pliocene, indicating increased aridification.[33] Further aridification of Central Asia was caused by the development of Northern Hemisphere glaciation during the Late Pliocene.[34] A sediment core from the northern South China Sea shows an increase in dust storm activity during the middle Pliocene.[35] The South Asian Summer Monsoon (SASM) increased in intensity after 2.95 Ma, likely because of enhanced cross-equatorial pressure caused by the reorganisation of the Indonesian Throughflow.[36]
In the south-central Andes, an arid period occurred from 6.1 to 5.2 Ma, with another occurring from 3.6 to 3.3 Ma. These arid periods are coincident with global cold periods, during which the position of the Southern Hemisphere westerlies shifted northward and disrupted the South American Low Level Jet, which brings moisture to southeastern South America.[37]
From around 3.8 Ma to about 3.3 Ma, North Africa experienced an extended humid period.[38] In northwestern Africa, tropical forests extended up to Cape Blanc during the Zanclean until around 3.5 Ma. During the Piacenzian, from about 3.5 to 2.6 Ma, the region was forested at irregular intervals and contained a significant Saharan palaeoriver until 3.35 Ma, when trade winds began to dominate over fluvial transport of pollen. Around 3.26 Ma, a strong aridification event that was followed by a return to more humid conditions, which was itself followed by another aridification around 2.7 Ma. From 2.6 to 2.4 Ma, vegetation zones began repeatedly shifting latitudinally in response to glacial-interglacial cycles.[39]
The climate of eastern Africa was very similar to what it is today. Unexpectedly, the expansion of grasslands in eastern Africa during this epoch appears to have been decoupled from aridification and not caused by it, as evidenced by their asynchrony.[40]
Southwestern Australia hosted
The equatorial Pacific Ocean
The extent of the
Paleogeography

Continents continued to
Africa's collision with Europe formed the Mediterranean Sea, cutting off the remnants of the Tethys Ocean. The border between the Miocene and the Pliocene is also the time of the Messinian salinity crisis.[48][49]
During the Late Pliocene, the Himalayas became less active in their uplift, as evidenced by sedimentation changes in the Bengal Fan.[50]
The land bridge between Alaska and Siberia (Beringia) was first flooded near the start of the Pliocene, allowing marine organisms to spread between the Arctic and Pacific Oceans. The bridge would continue to be periodically flooded and restored thereafter.[51]
Pliocene marine formations are exposed in northeast Spain,[52] southern California,[53] New Zealand,[54] and Italy.[55]
During the Pliocene parts of southern Norway and southern Sweden that had been near sea level rose. In Norway this rise elevated the Hardangervidda plateau to 1200 m in the Early Pliocene.[56] In Southern Sweden similar movements elevated the South Swedish highlands leading to a deflection of the ancient Eridanos river from its original path across south-central Sweden into a course south of Sweden.[57]
Environment and evolution of human ancestors
The Pliocene is bookended by two significant events in the evolution of human ancestors. The first is the appearance of the
Improvements in
Alternatives to the savanna hypothesis include the woodland/forest hypothesis, which emphasizes the evolution of hominins in closed habitats, or hypotheses emphasizing the influence of colder habitats at higher latitudes or the influence of seasonal variation. More recent research has emphasized the variability selection hypothesis, which proposes that variability in climate fostered development of hominin traits.[63] Improved climate proxies show that the Pliocene climate of east Africa was highly variable, suggesting that adaptability to varying conditions was more important in driving hominin evolution than the steady pressure of a particular habitat.[62]
Flora
The change to a cooler, drier, more seasonal climate had considerable impacts on Pliocene vegetation, reducing tropical species worldwide.
Fauna
Both marine and continental faunas were essentially modern, although continental faunas were a bit more primitive than today.
The land mass collisions meant great migration and mixing of previously isolated species, such as in the
Image gallery
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TheOliva sayana, from the Pliocene of Florida
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A gastropod and attached serpulid wormtube from the Pliocene of Cyprus
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The gastropod Turritella carinata from the Pliocene of Cyprus
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The limpet Diodora italica from the Pliocene of Cyprus
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Thescaphopod Dentaliumfrom the Pliocene of Cyprus
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The gastropod Aporrhais from the Pliocene of Cyprus
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The arcid bivalve Anadara from the Pliocene of Cyprus
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The pectenid bivalve Ammusium cristatum from the Pliocene of Cyprus
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Vermetid gastropod Petaloconchus intortus attached to a branch of the coral Cladocora from the Pliocene of Cyprus
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barnacles and sponge borings (Entobia) from the Pliocene of York River, Virginia
Mammals
million years ago ) |

In North America,
In
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Africa was dominated by hoofed animals, and primates continued their evolution, with australopithecines (some of the first hominins) and baboon-like monkeys such as the Dinopithecus appearing in the late Pliocene. Rodents were successful, and elephant populations increased. Cows and antelopes continued diversification and overtook pigs in numbers of species. Early giraffes appeared. Horses and modern rhinos came onto the scene. Bears, dogs and weasels (originally from North America) joined cats, hyenas and civets as the African predators, forcing hyenas to adapt as specialized scavengers. Most mustelids in Africa declined as a result of increased competition from the new predators, although Enhydriodon omoensis remained an unusually successful terrestrial predator.
South America was invaded by North American species for the first time since the
The
Birds

The predatory South American
Reptiles and amphibians
Bivalves
In the Western Atlantic, assemblages of bivalves exhibited remarkable stasis with regards to their basal metabolic rates throughout the various climatic changes of the Pliocene.[73]
Corals
The Pliocene was a high water mark for species diversity among Caribbean corals. From 5 to 2 Ma, coral species origination rates were relatively high in the Caribbean, although a noticeable extinction event and drop in diversity occurred at the end of this interval.[74]
Oceans
This article needs additional citations for verification. (May 2021) |
Oceans continued to be relatively warm during the Pliocene, though they continued cooling. The Arctic ice cap formed, drying the climate and increasing cool shallow currents in the North Atlantic. Deep cold currents flowed from the Antarctic.
The formation of the Isthmus of Panama about 3.5 million years ago[75] cut off the final remnant of what was once essentially a circum-equatorial current that had existed since the Cretaceous and the early Cenozoic. This may have contributed to further cooling of the oceans worldwide.
The Pliocene seas were alive with sea cows, seals, sea lions, sharks and whales.
See also
- List of fossil sites (with link directory)
Notes
- ^ Because of the 2009 reassignment of the Pliocene-Pleistocene boundary from 1.8 to 2.6 million years ago, older papers on Pliocene hominin evolution sometimes include events that would now be regarded as taking place in the early Pleistocene.
References
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- ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. September 2023. Retrieved 16 December 2024.
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- ^ "Pliocene". Merriam-Webster.com Dictionary. Merriam-Webster.
- ^ "Pliocene". Dictionary.com Unabridged (Online). n.d.
- ^ "Pleiocene". Dictionary.com Unabridged (Online). n.d.
- ^ See the 2014 version of the ICS geologic time scale Archived 2014-05-30 at the Wayback Machine
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- Letter from William Whewell to Charles Lyell dated 31 January 1831 in: Todhunter, Isaac, ed. (1876). William Whewell, D. D., Master of Trinity College, Cambridge: An account of his writings with selections from his literary and scientific correspondence. Vol. 2. London, England: Macmillan and Co. p. 111.
- Lyell, Charles (1833). Principles of Geology, …. Vol. 3. London, England: John Murray. p. 53. From p. 53: "We derive the term Pliocene from πλειων, major, and χαινος, recens, as the major part of the fossil testacea of this epoch are referrible to recent species*."
- ^ "Pliocene". Online Etymology Dictionary.
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- ^ Hulbert, Richard C. Jr. (2 August 2016). "Hemphillian North American Land Mammal Age". Fossil Species of Florida. Florida Museum. Retrieved 7 June 2021.
- ^ Hulbert, Richard C. Jr. (2 August 2016). "Blancan North American Land Mammal Age". Fossil Species of Florida. Florida Museum. Retrieved 7 June 2021.
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- ^ "The Pliocene epoch". University of California Museum of Paleontology. Retrieved 25 March 2008.
- doi:10.1029/2005PA001133. Archived from the original(PDF) on 22 October 2011.
- ^ Mason, John. "The last time carbon dioxide concentrations were around 400ppm: a snapshot from Arctic Siberia". Skeptical Science. Retrieved 30 January 2014.
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- ^ Lewis, Barry; et al. (2013). Understanding Humans: Introduction to Physical Anthropology and Archaeology (11th ed.). Belmont, CA: Wadsworth Publishing.
{{cite book}}
: CS1 maint: location missing publisher (link) - ^ Stringer CB (1994). "Evolution of early humans". In Jones S, Martin R, Pilbeam D (eds.). The Cambridge Encyclopedia of Human Evolution. Cambridge: Cambridge University Press. p. 242.
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Further reading
- Comins, Niel F.; William J. Kaufmann III (2005). Discovering the Universe (7th ed.). New York, NY: Susan Finnemore Brennan. ISBN 978-0-7167-7584-3.
- Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge UniversityPress.
- Ogg, Jim (June 2004). "Overview of Global Boundary Stratotype Sections and Points (GSSP's)". Archived from the original on 23 April 2006. Retrieved 30 April 2006.
- Van Andel, Tjeerd H. (1994). New Views on an Old Planet: a History of Global Change (2nd ed.). Cambridge: Cambridge University Press. ISBN 978-0-521-44243-5.
External links
- Mid-Pliocene Global Warming: NASA/GISS Climate Modeling
- Palaeos Pliocene
- PBS Change: Deep Time: Pliocene
- Possible Pliocene supernova
- "Supernova dealt deaths on Earth? Stellar blasts may have killed ancient marine life" Science News Online retrieved February 2, 2002
- UCMP Berkeley Pliocene Epoch Page
- Pliocene Microfossils: 100+ images of Pliocene Foraminifera
- Human Timeline (Interactive) – Smithsonian, National Museum of Natural History (August 2016).