Miocene

Miocene
Chronology
Etymology
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitEpoch
Stratigraphic unitSeries
Time span formalityFormal
Lower boundary definition
Lower boundary GSSPLemme-Carrosio Section, Carrosio, Italy
44°39′32″N 8°50′11″E / 44.6589°N 8.8364°E / 44.6589; 8.8364
Lower GSSP ratified1996[4]
Upper boundary definitionBase of the Thvera magnetic event (C3n.4n), which is only 96 ka (5 precession cycles) younger than the GSSP
Upper boundary GSSPHeraclea Minoa section, Heraclea Minoa, Cattolica Eraclea, Sicily, Italy
37°23′30″N 13°16′50″E / 37.3917°N 13.2806°E / 37.3917; 13.2806
Upper GSSP ratified2000[5]

The Miocene (/ˈm.əsn, --/ MY-ə-seen, -⁠oh-)[6][7] 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 Scottish geologist Charles Lyell; the name comes from the Greek words μείων (meíōn, "less") and καινός (kainós, "new")[8][9] and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has.[10] The Miocene is preceded by the Oligocene and is followed by the Pliocene.

As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages.[11][12] 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.

During the Early Miocene, Afro-Arabia collided with Eurasia, severing the connection between the Mediterranean and Indian Oceans, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. During the late Miocene, the connections between the Atlantic and Mediterranean closed, causing the Mediterranean Sea to nearly completely evaporate, in an event called the Messinian salinity crisis. The Strait of Gibraltar opened and the Mediterranean refilled at the Miocene–Pliocene boundary, in an event called the Zanclean flood.

The apes first evolved 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 (7.5–5.3 Ma) 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.[13]

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.[14]

  1. ^ 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.
  2. ^ Retallack, G. J. (1997). "Neogene Expansion of the North American Prairie". PALAIOS. 12 (4): 380–390. doi:10.2307/3515337. JSTOR 3515337. Retrieved 2008-02-11.
  3. ^ "ICS Timescale Chart" (PDF). www.stratigraphy.org.
  4. ^ Steininger, Fritz F.; M. P. Aubry; W. A. Berggren; M. Biolzi; A. M. Borsetti; Julie E. Cartlidge; F. Cati; R. Corfield; R. Gelati; S. Iaccarino; C. Napoleone; F. Ottner; F. Rögl; R. Roetzel; S. Spezzaferri; F. Tateo; G. Villa; D. Zevenboom (1997). "The Global Stratotype Section and Point (GSSP) for the base of the Neogene" (PDF). Episodes. 20 (1): 23–28. doi:10.18814/epiiugs/1997/v20i1/005.
  5. ^ Van Couvering, John; Castradori, Davide; Cita, Maria; Hilgen, Frederik; Rio, Domenico (September 2000). "The base of the Zanclean Stage and of the Pliocene Series" (PDF). Episodes. 23 (3): 179–187. doi:10.18814/epiiugs/2000/v23i3/005.
  6. ^ "Miocene". Dictionary.com Unabridged (Online). n.d.
  7. ^ "Miocene". Merriam-Webster.com Dictionary.
  8. ^ See:
  9. ^ Harper, Douglas. "Miocene". Online Etymology Dictionary. Retrieved 2016-01-20.
  10. ^ Lyell, Charles (1833). Principles of Geology, …. Vol. 3. London, England: John Murray. p. 54.
  11. ^ Gibson, M. E.; McCoy, J.; O'Keefe, J. M. K.; Otaño, N. B. Nuñez; Warny, S.; Pound, M. J. (2022). "Reconstructing Terrestrial Paleoclimates: A Comparison of the Co-Existence Approach, Bayesian and Probability Reconstruction Techniques Using the UK Neogene". Paleoceanography and Paleoclimatology. 37 (2): e2021PA004358. Bibcode:2022PaPa...37.4358G. doi:10.1029/2021PA004358. S2CID 245937316.
  12. ^ Steinthorsdottir, M.; Coxall, H. K.; Boer, A. M. de; Huber, M.; Barbolini, N.; Bradshaw, C. D.; Burls, N. J.; Feakins, S. J.; Gasson, E.; Henderiks, J.; Holbourn, A. E.; Kiel, S.; Kohn, M. J.; Knorr, G.; Kürschner, W. M.; Lear, C. H.; Liebrand, D.; Lunt, D. J.; Mörs, T.; Pearson, P. N.; Pound, M. J.; Stoll, H.; Strömberg, C. a. E. (2021). "The Miocene: The Future of the Past". Paleoceanography and Paleoclimatology. 36 (4): e2020PA004037. Bibcode:2021PaPa...36.4037S. doi:10.1029/2020PA004037. S2CID 234434792.
  13. ^ "BBC Nature - Miocene epoch videos, news and facts". BBC. Retrieved 2016-11-13.
  14. ^ Zhisheng, An; Kutzbach, John E.; Prell, Warren L.; Porter, Stephen C. (3 May 2001). "Evolution of Asian monsoons and phased uplift of the Himalaya–Tibetan plateau since Late Miocene times". Nature. 411 (6833): 62–66. Bibcode:2001Natur.411...62Z. doi:10.1038/35075035. PMID 11333976. S2CID 4398615.

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