The Neogene ( /ˈniːəˌdʒiːn/) (informally Upper Tertiary or Late Tertiary) 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).
During this period, mammals and birds continued to evolve into roughly modern forms, while other groups of life remained relatively unchanged. Early hominids, the ancestors of humans, appeared in Africa near the end of the period. Some continental movement took place, the most significant event being the connection of North and South America at the Isthmus of Panama, late in the Pliocene. This cut off the warm ocean currents from the Pacific to the Atlantic Ocean, leaving only the Gulf Stream to transfer heat to the Arctic Ocean. The global climate cooled considerably over the course of the Neogene, culminating in a series of continental glaciations in the Quaternary Period that follows.
23.03–2.58 million years ago
|Mean atmospheric O
2 content over period duration
|c. 21.5 vol %|
(108 % of modern level)
|Mean atmospheric CO
2 content over period duration
|c. 280 ppm|
(1 times pre-industrial level)
|Mean surface temperature over period duration||c. 14 °C|
(0 °C above modern level)
In ICS terminology, from upper (later, more recent) to lower (earlier):
The Pliocene Epoch is subdivided into 2 ages:
The Miocene Epoch is subdivided into 6 ages:
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.
The continents in the Neogene were very close to their current positions. The Isthmus of Panama formed, connecting North and South America. The Indian subcontinent continued to collide with Asia, forming the Himalayas. Sea levels fell, creating land bridges between Africa and Eurasia and between Eurasia and North America.
The global climate became seasonal and continued an overall drying and cooling trend which began at the start of the Paleogene. 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.
Marine and continental flora and fauna have a modern appearance. The reptile group Choristodera became extinct in the early part of the period, while the amphibians known as Allocaudata disappeared at the end. Mammals and birds continued to be the dominant terrestrial vertebrates, and took many forms as they adapted to various habitats. The first hominins, the ancestors of humans, may have appeared in southern Europe and migrated into Africa.
In response to the cooler, seasonal climate, tropical plant species gave way to deciduous 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 horses, antelope, and bison. Eucalyptus fossil leaves occur in the Miocene of New Zealand, where the genus is not native today, but have been introduced from Australia.
The Neogene traditionally ended at the end of the Pliocene Epoch, just before the older definition of the beginning of the Quaternary Period; many time scales show this division.
However, there was a movement amongst geologists (particularly marine geologists) 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 Era into three (arguably two) periods (Paleogene, Neogene, Quaternary) 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 (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 and Pliocene epochs. The International Union for Quaternary Research (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. 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 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.
From p. 806: "Das häufige Vorkommen der Wiener Mollusken … im trennenden Gegensatze zu den eocänen zusammenzufassen." (The frequent occurrence of Viennese mollusks in typical Miocene as well as in typical Pliocene deposits motivated me – in order to avoid the perpetual monotony [of providing] details about the deposits – to subsume both deposits provisionally under the name "Neogene" (νεος new and γιγνομαι to arise) in distinguishing contrast to the Eocene.)
The order Cathartiformes of raptors or birds of prey includes the New World vultures and the now extinct Teratornithidae. These raptors are classified by most taxonomic authorities in the order Accipitriformes (which includes the eagles and hawks). In the past they were considered to be a sister group to the storks of the order Ciconiiformes based on DNA-DNA hybridization and morphology.Caviidae
Caviidae, the cavy family, is composed of rodents native to South America and includes the domestic guinea pig, wild cavies, and the largest living rodent, the capybara. They are found across South America in open areas from moist savanna to thorn forests or scrub desert. This family of rodents has fewer members than most other rodent families, with 19 species in 6 genera in 3 subfamilies.Early Miocene
The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene Epoch made up of two stages: the Aquitanian and Burdigalian stages.
The sub-epoch lasted from 23.03 ± 0.05 Ma to 15.97 ± 0.05 Ma (million years ago). It was preceded by the Oligocene epoch. As the climate started to get cooler, the landscape started to change. New mammals evolved to replace the extinct animals of the Oligocene epoch.The first members of the hyena and weasel family started to evolve to replace the extinct Hyaenodon, entelodonts and bear-dogs. The chalicotheres survived the Oligocene epoch. A new genus of entelodont called Daeodon evolved in order to adapt to the new habitats and hunt the new prey animals of the Early Miocene epoch; it quickly became the top predator of North America. But it became extinct due to competition from Amphicyon, a newcomer from Eurasia. Amphicyon bested Daeodon because the bear-dog's larger brain, sharper teeth and longer legs built for longer chases helped it to overcome its prey.Elseya nadibajagu
Elseya nadibajagu is a Pliocene species of extinct Australian snapping turtle, described from the Bluff Downs region of Queensland, Australia.Gryposuchus
Gryposuchus is an extinct genus of gavialoid crocodilian. It is the type genus of the subfamily Gryposuchinae. Fossils have been found from Argentina, Colombia, Venezuela, Brazil and the Peruvian Amazon. The genus existed from the Middle Miocene to Late Pleistocene (Friasian to Lujanian). One recently described species, G. croizati, grew to an estimated length of 10 metres (33 ft).List of fossiliferous stratigraphic units in California
This article contains a list of fossil-bearing stratigraphic units in the state of California, U.S.List of fossiliferous stratigraphic units in Mexico
This is a list of stratigraphic units (groups, formations and members), containing fossils and pertaining to the North American country of Mexico.List of fossiliferous stratigraphic units in Nevada
This article contains a list of fossil-bearing stratigraphic units in the state of Nevada, U.S.Mesoeucrocodylia
Mesoeucrocodylia is the clade that includes Eusuchia and crocodyliforms formerly placed in the paraphyletic group Mesosuchia. The group appeared during the Early Jurassic, and continues to the present day.Metasuchia
Metasuchia is a major clade within the superorder Crocodylomorpha. It is split into two main groups, Notosuchia and Neosuchia. Notosuchia is an extinct group that contains primarily small-bodied Cretaceous taxa with heterodont dentition. Neosuchia includes the extant crocodylians and basal taxa, such as peirosaurids and pholidosaurids. It is phylogenetically defined by Sereno et al. (2001) as a clade containing Notosuchus terrestris, Crocodylus niloticus, and all descendants of their common ancestor.Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about 23.03 to 5.333 million years ago (Ma). The Miocene was named by Charles Lyell; its name comes from the Greek words μείων (meiōn, “less”) and καινός (kainos, “new”) 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.
As the earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch.
The Apes first evolved, arose, and diversified during the early Miocene (Aquitanian and Burdigalian stages), becoming widespread in the Old World. By the end of this epoch and the start of the following one, the ancestors of humans had split away from the ancestors of the chimpanzees to follow their own evolutionary path during the final Messinian stage (7.2 - 5.3 mya) of the Miocene. As in the Oligocene before it, grasslands continued to expand and forests to dwindle in extent. In the seas of the Miocene, kelp forests made their first appearance and soon became one of Earth's most productive ecosystems.The plants and animals of the Miocene were recognizably modern. Mammals and birds were well-established. Whales, pinnipeds, and kelp spread.
The Miocene is of particular interest to geologists and palaeoclimatologists as major phases of the geology of the Himalaya occurred during the Miocene, affecting monsoonal patterns in Asia, which were interlinked with glacial periods in the northern hemisphere.Mourasuchus
Mourasuchus is an extinct genus of giant, aberrant caiman from the Miocene of South America. Its skull has been described as duck like, being broad, flat and very elongate, closely resembling what is seen in Stomatosuchus, an unrelated crocodylian that may also have had a large gular sac similar to those of pelicans or baleen whales. Mourasuchus, is a strange nettosuchid with an unusually long, broad snout.The synonym Carandaisuchus was used to describe fossils from the Ituzaingó Formation in Argentina demonstrating a pronounced bony occipital crest.Northwestern Hawaiian Islands
The Northwestern Hawaiian Islands or the Leeward Islands are the small islands and atolls in the Hawaiian island chain located northwest (in some cases, far to the northwest) of the islands of Kauai and Niihau. Politically, they are all part of Honolulu County in the U.S. state of Hawaii, except Midway Atoll, which is a territory distinct from Hawaii and grouped as one of the United States Minor Outlying Islands. The United States Census Bureau defines this area, except Midway, as Census Tract 114.98 of Honolulu County. Its total land area is 3.1075 square miles (8.048 km2). All the islands except Nihoa are north of the Tropic of Cancer, making them the only islands in Hawaii that lie outside the tropics.
The Northwestern or Leeward Hawaiian Islands include:
Nihoa (Moku Manu) at 23°03′38″N 161°55′19″W
Necker (Mokumanamana) at 23°34′N 164°42′W
French Frigate Shoals (Kānemilohaʻi) at 23°52.134′N 166°17.16′W
Gardner Pinnacles (Pūhāhonu) at 25°01′N 167°59′W
Maro Reef (Nalukākala) at 25.415°N 170.590°W / 25.415; -170.590
Laysan (Kauō) at 25.7675°N 171.7334°W / 25.7675; -171.7334
Lisianski (Papaāpoho) at 26.064031°N 173.965802°W / 26.064031; -173.965802
Pearl and Hermes Atoll (Holoikauaua) at 27.927687°N 175.737991°W / 27.927687; -175.737991
Midway (Pihemanu) at 28°12′N 177°21′W - not part of the State of Hawaii
Kure (Mokupāpapa) at 28°25′N 178°20′WPholadomya
Pholadomya is a genus of fossil saltwater clams, marine bivalve mollusks in the family Pholadomyidae. Fossils species within this genus lived during the Mesozoic era, in the opening South Atlantic, between present-day Brazil and Africa. In the Triassic of Argentina, Austria, Hungary, and Italy fossils have been found. They are found in the Jurassic of the Coquina Group, La Guajira, Colombia among many other places. Of Campanian age, this genus is widespread as a fossil in Cameroon, France, Poland, Austria, Germany and the USA. Fossils up to the Neogene have been found in Belgium, the United Kingdom, and Venezuela (Pliocene Mare and Playa Grande Formations) and Miocene Bulgaria, Chile, Colombia, Cyprus, Germany, India, Japan, Malta, Moldova, New Zealand, Panama, Poland, the Russian Federation, Slovakia, Trinidad and Tobago, and Venezuela.Pliocene
The Pliocene ( ; 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.Purussaurus
Purussaurus is an extinct genus of giant caiman that lived in South America during the Miocene epoch, from the Colhuehuapian to the Montehermosan in the SALMA classification. It is known from skull material found in the Brazilian and Peruvian Amazon, Colombian Villavieja Formation, Panamanian Culebra Formation and the Urumaco and Socorro Formations of northern Venezuela. This indicates how widespread the wetlands such a large caiman would require to survive were across South America in the Miocene.Stupendemys
Stupendemys is a prehistoric genus of freshwater side-necked turtle. Its fossils have been found in northern South America, in rocks dating from the late Miocene to the very start of the Pliocene, about 9 to 5 million years ago.Zanclean
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 (million years ago). It is preceded by the Messinian age of the Miocene epoch, and followed by the Piacenzian age.
The Zanclean can be correlated with regionally used stages, such as the Tabianian or Dacian of Central Europe. It also corresponds to the late Hemphillian to mid-Blancan North American Land Mammal Ages. In California, the Zanclean roughly corresponds to the mid-Delmontian Californian Stage of from 7.5 To 2.9 Ma ago.
(541.0 Mya–2.5 Gya)
|Archean eon (2.5–4 Gya)|
|Hadean eon (4–4.6 Gya)|
|History of geology|
|Сomposition and structure|