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|Subdivision of the Neogene Period|
according to the ICS, as of 2017.
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The Pliocene ( /, -/ PLY-ə-seen, PLY-oh-; also Pleiocene ) Epoch is the epoch in the geologic timescale that extends from 5.333 million to 2.58 million years BP. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch. Prior to the 2009 revision of the geologic time scale, which placed the four most recent major glaciations entirely within the Pleistocene, the Pliocene also included the Gelasian stage, which lasted from 2.588 to 1.806 million years ago, and is now included in the Pleistocene.
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 Pliocene. The upper boundary was set at the start of the Pleistocene glaciations.
Charles Lyell (later Sir Charles) gave the Pliocene its name in Principles of Geology (volume 3, 1833).
The word pliocene comes from the Greek words πλεῖον (pleion, "more") and καινός (kainos, "new" or "recent") and means roughly "continuation of the recent", referring to the essentially modern marine mollusc fauna.
|Epoch||Literally||First Element||Second Element|
|Holocene||whole-new||ὅλος||holos||"whole" or "entire"||καινός||kainós|
(Latinized as cænus)
These reflect the understanding that these are all new relative to the Mesozoic ("middle life" - the age of dinosaurs) and Paleozoic ("old life" - Trilobites, coal forests, and the earliest Synapsida) eras.[ citation needed ][ original research? ]
In the official timescale of the ICS, the Pliocene is subdivided into two stages. From youngest to oldest they are:
The Piacenzian is sometimes referred to as the Late Pliocene, whereas the Zanclean is referred to as the Early Pliocene.
In the system of
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 Britain the Pliocene is divided into the following stages (old to young): Gedgravian, Waltonian, Pre-Ludhamian, Ludhamian, Thurnian, Bramertonian or Antian, Pre-Pastonian or Baventian, Pastonian and Beestonian. In the Netherlands the Pliocene is divided into these stages (old to young): Brunssumian C, Reuverian A, Reuverian B, Reuverian C, Praetiglian, Tiglian A, Tiglian B, Tiglian C1-4b, Tiglian C4c, Tiglian C5, Tiglian C6 and Eburonian. The exact correlations between these local stages and the International Commission on Stratigraphy (ICS) stages is still a matter of detail.
The global average temperature in the mid-Pliocene (3.3–3 mya) was 2–3 °C higher than today, carbon dioxide levels were the same as today, and global sea level was 25 m higher. The northern hemisphere ice sheet was ephemeral before the onset of extensive glaciation over Greenland that occurred in the late Pliocene around 3 Ma. The formation of an Arctic ice cap is signaled by an abrupt shift in oxygen isotope ratios and ice-rafted cobbles in the North Atlantic and North Pacific ocean beds. Mid-latitude glaciation was probably underway before the end of the epoch. The global cooling that occurred during the Pliocene may have spurred on the disappearance of forests and the spread of grasslands and savannas.
Continents continued to drift, moving from positions possibly as far as 250 km from their present locations to positions only 70 km from their current locations. South America became linked to North America through the Isthmus of Panama during the Pliocene, making possible the Great American Interchange and bringing a nearly complete end to South America's distinctive large marsupial predator and native ungulate faunas. The formation of the Isthmus had major consequences on global temperatures, since warm equatorial ocean currents were cut off and an Atlantic cooling cycle began, with cold Arctic and Antarctic waters dropping temperatures in the now-isolated Atlantic Ocean.
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.
Sea level changes exposed the land bridge between Alaska and Asia (Beringia).
Pliocene marine rocks are well exposed in the Mediterranean, India, and China. Elsewhere, they are exposed largely near shores.
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.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.
The change to a cooler, dry, seasonal climate had considerable impacts on Pliocene vegetation, reducing tropical species worldwide. Deciduous forests proliferated, coniferous forests and tundra covered much of the north, and grasslands spread on all continents (except Antarctica). Tropical forests were limited to a tight band around the equator, and in addition to dry savannahs, deserts appeared in Asia and Africa.
Both marine and continental faunas were essentially modern, although continental faunas were a bit more primitive than today. The first recognizable hominins, the australopithecines, appeared in the Pliocene.
The land mass collisions meant great migration and mixing of previously isolated species, such as in the Great American Interchange. Herbivores got bigger, as did specialized predators.
In North America, rodents, large mastodons and gomphotheres, and opossums continued successfully, while hoofed animals (ungulates) declined, with camel, deer and horse all seeing populations recede. Rhinos, three toed horses ( Nannippus ), oreodonts, protoceratids, and chalicotheres became extinct. Borophagine dogs and Agriotherium became extinct, but other carnivores including the weasel family diversified, and dogs and short-faced bears did well. Ground sloths, huge glyptodonts, and armadillos came north with the formation of the Isthmus of Panama.
In Eurasia rodents did well, while primate distribution declined. Elephants, gomphotheres and stegodonts were successful in Asia, and hyraxes migrated north from Africa. Horse diversity declined, while tapirs and rhinos did fairly well. Cows and antelopes were successful, and some camel species crossed into Asia from North America. Hyenas and early saber-toothed cats appeared, joining other predators including dogs, bears and weasels.
Africa was dominated by hoofed animals, and primates continued their evolution, with australopithecines (some of the first hominins) appearing in the late Pliocene. Rodents were successful, and elephant populations increased. Cows and antelopes continued diversification and overtaking 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.
South America was invaded by North American species for the first time since the Cretaceous, with North American rodents and primates mixing with southern forms. Litopterns and the notoungulates, South American natives, were mostly wiped out, except for the macrauchenids and toxodonts, which managed to survive. Small weasel-like carnivorous mustelids, coatis and short-faced bears migrated from the north. Grazing glyptodonts, browsing giant ground sloths and smaller caviomorph rodents, pampatheres, and armadillos did the opposite, migrating to the north and thriving there.
The marsupials remained the dominant Australian mammals, with herbivore forms including wombats and kangaroos, and the huge Diprotodon . Carnivorous marsupials continued hunting in the Pliocene, including dasyurids, the dog-like thylacine and cat-like Thylacoleo . The first rodents arrived in Australia. The modern platypus, a monotreme, appeared.
The predatory South American phorusrhacids were rare in this time; among the last was Titanis , a large phorusrhacid that migrated to North America and rivaled mammals as top predator. Other birds probably evolved at this time, some modern (such as the genera Cygnus , Bubo , Struthio and Corvus ), some now extinct.
Alligators and crocodiles died out in Europe as the climate cooled. Venomous snake genera continued to increase as more rodents and birds evolved. Rattlesnakes first appeared in the Pliocene. The modern species Alligator mississippiensis , having evolved in the Miocene, continued into the Pliocene, except with a more northern range; specimens have been found in very late Miocene deposits of Tennessee. Giant tortoises still thrived in North America, with genera like Hesperotestudo . Madtsoid snakes were still present in Australia. The amphibian order Allocaudata became extinct.
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 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 and sharks.
In 2002, Narciso Benítez et al. calculated that roughly 2 million years ago, around the end of the Pliocene epoch, a group of bright O and B stars called the Scorpius-Centaurus OB association passed within 130 light-years of Earth and that one or more supernova explosions gave rise to a feature known as the Local Bubble.Such a close explosion could have damaged the Earth's ozone layer and caused the extinction of some ocean life (at its peak, a supernova of this size could have the same absolute magnitude as an entire galaxy of 200 billion stars). Radioactive Iron-60 isotopes that have been found in ancient seabed deposits further back this hypothesis as there are no natural sources for this radioactive isotope on Earth, and so it must be of supernova origin. Furthermore, Iron-60 residues point to a huge spike 2.6 million years ago, but an excess scattered over 10 million years can also be found suggesting that there may have been multiple supernovae.
In 2019, researchers have found more of these interstellar Iron-60 isotopes in Antarctica, which have been associated with the Local Interstellar Cloud where the Solar System resides.
The Cenozoic Era meaning "new life" is the current and most recent of the three Phanerozoic geological eras, following the Mesozoic Era and extending from 66 million years ago to the present day. It is generally believed to have started on the day of the Cretaceous–Paleogene extinction event when an asteroid hit the earth.
The Miocene is the first geological epoch of the Neogene Period and extends from about(Ma). The Miocene was named by Charles Lyell; its name comes from the Greek words μείων and καινός and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene is preceded by the Oligocene and is followed by the Pliocene.
The Neogene is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period 23.03 million years ago (Mya) to the beginning of the present Quaternary Period 2.58 Mya. The Neogene is sub-divided into two epochs, the earlier Miocene and the later Pliocene. Some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the Quaternary. The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes (1815–1868).
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present. As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich; the name comes from the Ancient Greek ὀλίγος and καινός, and refers to the sparsity of extant forms of molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period.
The Pleistocene is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the world's most recent period of repeated glaciations. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology.
Tertiary is a widely used, but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start of the Cenozoic Era, and extended to the beginning of the Quaternary glaciation at the end of the Pliocene Epoch. The time span covered by the Tertiary has no exact equivalent in the current geologic time system, but it is essentially the merged Paleogene and Neogene periods, which are informally called the Lower Tertiary and the Upper Tertiary, respectively.
There have been five or six major ice ages in the history of Earth over the past 3 billion years. The Late Cenozoic Ice Age began 34 million years ago, its latest phase being the Quaternary glaciation, in progress since 2.58 million years ago.
The Zanclean is the lowest stage or earliest age on the geologic time scale of the Pliocene. It spans the time between 5.332 ± 0.005 Ma and 3.6 ± 0.005 Ma. It is preceded by the Messinian age of the Miocene epoch, and followed by the Piacenzian age.
The Bramertonian Stage is the name for an early Pleistocene biostratigraphic stage in the British Isles. It precedes the Pre-Pastonian Stage. It derives its name from Bramerton Pits in Norfolk, where the deposits can be found on the surface. The exact timing of the beginning and end of the Bramertonian Stage is currently unknown. It is only known that it is equivalent to the Tiglian C1-4b Stage of Europe and early Pre-Illinoian Stage of North America. It lies somewhere in time between Marine Oxygen Isotope stages 65 to 95 and somewhere between 1.816 and 2.427 Ma. The Bramertonian is correlated with the Antian stage identified from pollen assemblages in the Ludham borehole.
The Gelasian is an age in the international geologic timescale or a stage in chronostratigraphy, being the earliest or lowest subdivision of the Quaternary period/system and Pleistocene epoch/series. It spans the time between 2.588 ± 0.005 Ma and 1.806 ± 0.005 Ma. It follows the Piacenzian stage and is followed by the Calabrian stage.
The Piacenzian is in the international geologic time scale the upper stage or latest age of the Pliocene. It spans the time between 3.6 ± 0.005 Ma and 2.588 ± 0.005 Ma. The Piacenzian is after the Zanclean and is followed by the Gelasian.
The Messinian is in the geologic timescale the last age or uppermost stage of the Miocene. It spans the time between 7.246 ± 0.005 Ma and 5.333 ± 0.005 Ma. It follows the Tortonian and is followed by the Zanclean, the first age of the Pliocene.
Calabrian is a subdivision of the Pleistocene Epoch of the geologic time scale, defined as ~1.8 Ma.—781,000 years ago ± 5,000 years, a period of ~.
The Serravallian is in the geologic timescale an age or a stage in the middle Miocene epoch/series, that spans the time between 13.82 Ma and 11.63 Ma. The Serravallian follows the Langhian and is followed by the Tortonian.
The Blancan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 4,750,000 to 1,806,000 years BP, a period of. It is usually considered to start in the early-mid Pliocene Epoch and end by the early Pleistocene. The Blancan is preceded by the Hemphillian and followed by the Irvingtonian NALMA stages.
The geological history of Earth follows the major events in Earth's past based on the geological time scale, a system of chronological measurement based on the study of the planet's rock layers (stratigraphy). Earth formed about 4.54 billion years ago by accretion from the solar nebula, a disk-shaped mass of dust and gas left over from the formation of the Sun, which also created the rest of the Solar System.
The Paratethys ocean, Paratethys sea or just Paratethys was a large shallow inland sea that stretched from the region north of the Alps over Central Europe to the Aral Sea in Central Asia. The sea was formed during the Oxfordian stage of the Late Jurassic as an extension of the rift that formed the Central Atlantic Ocean and was isolated during the Oligocene epoch. It was separated from the Tethys Ocean to the south by the formation of the Alps, Carpathians, Dinarides, Taurus and Elburz mountains. During its long existence the Paratethys was at times reconnected with the Tethys or its successors, the Mediterranean Sea or Indian Ocean. From the Pliocene epoch onward, the Paratethys became progressively shallower. Today's Black Sea, Caspian Sea, Aral Sea, Lake Urmia, Namak Lake and others are remnants of the Paratethys Sea.
The Choctaw Sea was a Cenozoic eutropical subsea, which along with the Okeechobean Sea, occupied the eastern Gulf of Mexico basin system bounding Florida.
The Okeechobean Sea was a Cenozoic eutropical subsea, which along with the Choctaw Sea, occupied the eastern Gulf of Mexico basin system bounding Florida.
During the Pliocene epoch climate became cooler and drier, and seasonal, similar to modern climates.
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