Neogene

The Neogene ( /ˈniːəˌdʒiːn/)[6][7] (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).[8]

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.

Neogene Period
23.03–2.58 million years ago
N
Mean atmospheric O
2
content over period duration
c. 21.5 vol %[1][2]
(108 % of modern level)
Mean atmospheric CO
2
content over period duration
c. 280 ppm[3]
(1 times pre-industrial level)
Mean surface temperature over period duration c. 14 °C[4]
(0 °C above modern level)
Key events in the Neogene
-24 —
-22 —
-20 —
-18 —
-16 —
-14 —
-12 —
-10 —
-8 —
-6 —
-4 —
-2 —
0 —
Holocene begins 11.7 ka ago
An approximate timescale of key Neogene events.
Vertical axis: millions of years ago.

Divisions

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.

Geography

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.

Climate

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.

Flora and fauna

Miocene
Scene featuring Miocene (Early Neogene) fauna

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.[9][10]

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.[11]

Disagreements

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.[12] 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.[13] 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.[14][15] 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.[16]

Following formal discussions at the 2008 International Geological Congress in Oslo, Norway,[17] 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.[18] Thus the Neogene Period ends bounding the succeeding Quaternary Period at 2.58 Mya.

References

  1. ^ Image:Sauerstoffgehalt-1000mj.svg
  2. ^ File:OxygenLevel-1000ma.svg
  3. ^ Image:Phanerozoic Carbon Dioxide.png
  4. ^ Image:All palaeotemps.png
  5. ^ Krijgsman, W.; Garcés, M.; Langereis, C. G.; Daams, R.; Van Dam, J.; Van Der Meulen, A. J.; Agustí, J.; Cabrera, L. (1996). "A new chronology for the middle to late Miocene continental record in Spain". Earth and Planetary Science Letters. 142 (3–4): 367–380. Bibcode:1996E&PSL.142..367K. doi:10.1016/0012-821X(96)00109-4.
  6. ^ "Neogene". Merriam-Webster Dictionary.
  7. ^ "Neogene". Dictionary.com Unabridged. Random House.
  8. ^ Hörnes, Moritz (1853). "Mittheilungen an Professor Bronn gerichtet" [Reports addressed to Professor Bronn]. Neues Jahrbuch für Mineralogie, Geognosie, Geologie und Petrefakten-kunde [New Yearbook for Mineralogy, Geognosy, Geology, and the Study of Fossils] (in German): 806–810. hdl:2027/hvd.32044106271273. 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.)
  9. ^ "Scientists find 7.2-million-year-old pre-human remains in the Balkans". Phys.org. Retrieved 17 December 2017.
  10. ^ "9.7 million-year-old teeth found in Germany resemble those of human ancestors in Africa". ResearchGate. Retrieved 17 December 2017.
  11. ^ "Eucalyptus fossils in New Zealand - the thin end of the wedge - Mike Pole".
  12. ^ Tucker, M.E. (2001). Sedimentary petrology : an introduction to the origin of sedimentary rocks (3rd ed.). Osney Nead, Oxford, UK: Blackwell Science. ISBN 978-0-632-05735-1.
  13. ^ Lourens, L., Hilgen, F., Shackleton, N.J., Laskar, J., Wilson, D., (2004) “The Neogene Period”. In: Gradstein, F., Ogg, J., Smith, A.G. (Eds.), Geologic Time Scale, Cambridge University Press, Cambridge.
  14. ^ Clague, John et al. (2006) "Open Letter by INQUA Executive Committee" Archived 2006-09-23 at the Wayback Machine Quaternary Perspective, the INQUA Newsletter International Union for Quaternary Research 16(1)
  15. ^ Clague, John; et al. (2006). "Open Letter by INQUA Executive Committee" (PDF). Quaternary Perspective, the INQUA Newsletter. International Union for Quaternary Research. 16 (1): 158–159. doi:10.1016/j.quaint.2006.06.001. ISSN 1040-6182. Archived from the original (PDF) on 2006-09-23. Retrieved 2006-09-23.
  16. ^ "ICS: Consolidated Annual Report for 2006" (PDF). Stratigraphy.org. Retrieved 15 June 2007.
  17. ^ "Geoparks and Geotourism - Field Excursion of South America". 33igc.org. Retrieved 17 December 2017.
  18. ^ "See the 2009 version of the ICS geologic time scale". Quaternary.stratigraphy.org.uk. Retrieved 17 December 2017.

External links

Cathartiformes

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′W

Pholadomya

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.

Neogene Period
Cenozoic era
(present–66.0 Mya)
Mesozoic era
(66.0–251.902 Mya)
Paleozoic era
(251.902–541.0 Mya)
Proterozoic eon
(541.0 Mya–2.5 Gya)
Archean eon (2.5–4 Gya)
Hadean eon (4–4.6 Gya)
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Сomposition and structure
Historical geology
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