Pliocene

From Encyclopedia Britannia
Jump to navigation Jump to search
Pliocene
5.333 – 2.58 Ma
↓
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 definitionBase of the Thvera magnetic event (C3n.4n), which is only 96 ka (5 precession cycles) younger than the GSSP
Lower 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
GSSP ratified2000[4]
Upper boundary definition
Upper boundary GSSPMonte San Nicola Section, Gela, Sicily, Italy
37°08′49″N 14°12′13″E / 37.1469°N 14.2035°E / 37.1469; 14.2035
GSSP ratified2009 (as base of Quaternary and Pleistocene)[5]
Part of a series on
Human history
and prehistory
↑ before Homo   (Pliocene epoch)
Prehistory
(three-age system)
Stone Age
Lower Paleolithic
Middle Paleolithic 
Early Homo sapiens
Upper Paleolithic
Behavioral modernity
Neolithic 
Cradle of civilization
Protohistory
Chalcolithic
Bronze Age
Bronze Age collapse
Iron Age
Recorded history
Ancient history
Post-classical history
Modern history
↓ Future   (Holocene epoch)

The Pliocene ( /ˈplaɪ.əˌsiːn, ˈplaɪ.oʊ-/ PLY-ə-seen, PLY-oh-;[6][7] also Pleiocene[8]) Epoch is the epoch in the geologic timescale that extends from 5.333 million to 2.58[9] 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.[10]

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.

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")[12] and means roughly "continuation of the recent", referring to the essentially modern marine mollusc fauna.

Subdivisions

Some schemes for subdivisions of the Pliocene

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.[18]

Climate

Main article: Pliocene climate
Mid-Pliocene reconstructed annual sea surface temperature anomaly

The global average temperature in the mid-Pliocene (3.3–3 mya) was 2–3 °C higher than today,[19] carbon dioxide levels were the same as today,[20] and global sea level was 25 m higher.[21] The northern hemisphere ice sheet was ephemeral before the onset of extensive glaciation over Greenland that occurred in the late Pliocene around 3 Ma.[22] 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.[23] 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.[24]

Paleogeography

Examples of migrant species in the Americas after the formation of the Isthmus of Panama. Olive green silhouettes denote North American species with South American ancestors; blue silhouettes denote South American species of North American origin.

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.[25] 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.[26]

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.[27][28]

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.[29]

Pliocene marine formations are exposed in northeast Spain,[30] southern California,[31] New Zealand,[32] and Italy.[33]

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.[34] 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.[35]

Flora

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.[36][failed verification]

Fauna

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.

  • The gastropod Oliva sayana, from the Pliocene of Florida.

  • The coral Cladocora from the Pliocene of Cyprus.

  • A gastropod and attached serpulid wormtube from the Pliocene of Cyprus.

  • The gastropod Turritella carinata from the Pliocene of Cyprus.

  • The thorny oyster Spondylus right and left valve interiors from the Pliocene of Cyprus.

  • Articulated Spondylus from the Pliocene of Cyprus.

  • The limpet Diodora italica from the Pliocene of Cyprus.

  • The scaphopod Dentalium from the Pliocene of Cyprus.

  • The gastropod Aporrhais from the Pliocene of Cyprus.

  • The arcid bivalve Anadara from the Pliocene of Cyprus.

  • The pectenid bivalve Ammusium cristatum from the Pliocene of Cyprus.

  • Vermetid gastropod Petaloconchus intortus attached to a branch of the coral Cladocora from the Pliocene of Cyprus.

  • Chesapecten, barnacles and sponge borings (Entobia) from the Pliocene of York River, Virginia, USA.]]

Mammals

19th century artist's impression of a Pliocene landscape

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.

Human evolution during the Pliocene

<timeline> ImageSize = width:350 height:230 PlotArea = left:20 right:20 bottom:20 top:0 AlignBars = justify

Colors = 

 id:color1  value:rgb(1,1,0.7) # light yellow
 id:color2  value:rgb(0.7,0.7,1) # light blue
 id:color3  value:rgb(0.7,1,0.7) # light green
 id:color4  value:rgb(1,0.9216,0.3843) # 255/235/98
 id:events  value:rgb(1,0.3,1) # light purple

Period = from:1806000 till:5332000 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:1000000 start:2000000 ScaleMinor = unit:year increment:250000 start:2000000

BarData = 

 bar:Events
 bar:bar0
 bar:bar1
 bar:bar2
 bar:bar3
 bar:bar4
 bar:bar5
 bar:bar6
 bar:bar7
 bar:bar8
 bar:bar9
 bar:bar10
 bar:bar11
 bar:bar12
 bar:bar13
 bar:bar14
 bar:bar15
 bar:bar16
 bar:bar17
 bar:bar18
 bar:bar19

PlotData= 

 width:15  mark:(line,red)  textcolor:black

 bar:Events  color:events  align:right  shift:(-5,10)
   at:5000000  text:"Split between Homo and Pan~using molecular clock, about 7 Ma"

 width:7  mark:none  color:events  align:right  shift:(-5,-4)

 bar:bar3
   from:5200000  till:end
   at:5200000  text:Ar. kadabba
 bar:bar5
   from:4200000  till:end
   at:4200000  text:Ar. ramidus

 align:left  shift:(5,-4)

 bar:bar7
   from:3900000  till:4400000
   at:4400000  text:A. anamensis
 bar:bar9
   from:3000000  till:3900000
   at:3900000  text:A. afarensis
 bar:bar11
   from:3000000  till:3500000
   at:3500000  text:A. bahrelghazali
 bar:bar13
   from:2400000  till:3300000
   at:3300000  text:A. africanus
 bar:bar15
   from:2000000  till:3000000
   at:3000000  text:A. garhi

 bar:bar17
   from:start  till:2500000
   at:2500000  text:H. habilis
 bar:bar19
   from:start  till:1900000
   at:1900000  text:H. erectus

 bar:bar7
   from:2500000  till:2700000
   at:2700000  text:P. aethiopicus
 bar:bar5
   from:start  till:2600000
   at:2600000  text:P. boisei
 bar:bar3
   from:start  till:2000000
   at:2000000  text:P. robustus

 mark:none
 bar:bar1  at:start  text:Genus Paranthropus
 bar:bar5  from:1806000  till:2735000  width:45  color:color1
 bar:bar5  from:1856000  till:2665000  width:35  color:white

 bar:bar1  at:end  align:right  shift:(-5,-4)  text:Genus Ardipithecus
 bar:bar4  from:4165000  till:5332000  width:29  color:color4
 bar:bar4  from:4235000  till:5282000  width:19  color:white

 bar:bar17  at:end  align:right  shift:(-5,-6)  text:Genus Australopithecus
 bar:bar11  from:1965000  till:4435000  width:71  color:color2
 bar:bar11  from:2035000  till:4365000  width:61  color:white

 bar:bar19  at:2535000  shift:(10,-10)  text:Genus Homo
 bar:bar18  from:1806000  till:2535000  width:29  color:color3
 bar:bar18  from:1856000  till:2465000  width:19  color:white

TextData = 

 pos:(59,14)
 text:"Years"

</timeline>

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 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.

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.

Birds

Titanis

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.

Reptiles and amphibians

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

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[37] 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.

Supernovae

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.[38] 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).[39][40] Radioactive iron-60 isotopes that have been found in ancient seabed deposits further back this finding, as there are no natural sources for this radioactive isotope on Earth, but they can be produced in supernovae.[41] 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, relatively close supernovae.[42]

In 2019, researchers found more of these interstellar iron-60 isotopes in Antarctica, which have been associated with the Local Interstellar Cloud.[43]

See also

References

  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. ↑ 4.0 4.1 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.
  5. ↑ Gibbard, Philip; Head, Martin (September 2010). "The newly-ratified definition of the Quaternary System/Period and redefinition of the Pleistocene Series/Epoch, and comparison of proposals advanced prior to formal ratification" (PDF). Episodes. 33 (3): 152–158. doi:10.18814/epiiugs/2010/v33i3/002. Retrieved 8 December 2020.
  6. ↑ "Pliocene". Merriam-Webster Dictionary.
  7. ↑ "Pliocene". Dictionary.com Unabridged. Random House.
  8. ↑ "Pleiocene". Dictionary.com Unabridged. Random House.
  9. ↑ See the 2014 version of the ICS geologic time scale Archived 2014-05-30 at the Wayback Machine
  10. ↑ Ogg, James George; Ogg, Gabi; Gradstein F. M. (2008). The Concise Geologic Time Scale. Cambridge University Press. pp. 150–1. ISBN 9780521898492.
  11. ↑ See:
  12. ↑ "Pliocene". Online Etymology Dictionary.
  13. ↑ Castradori, D.; Rio, D.; Hilgen, F. J.; Lourens, L. J. (1998). "The Global Standard Stratotype-section and Point (GSSP) of the Piacenzian Stage (Middle Pliocene)". Episodes. 21 (2): 88–93. doi:10.18814/epiiugs/1998/v21i2/003.
  14. ↑ Tedford, Richard H.; Albright, L. Barry; Barnosky, Anthony D.; Ferrusquia-Villafranca, Ismael; Hunt, Robert M.; Storer, John E.; Swisher, Carl C.; Voorhies, Michael R.; Webb, S. David; Whistler, David P. (2004-12-31). "6. Mammalian Biochronology of the Arikareean Through Hemphillian Interval (Late Oligocene Through Early Pliocene Epochs)". Late Cretaceous and Cenozoic Mammals of North America: 169–231. doi:10.7312/wood13040-008.
  15. ↑ Hulbert, Richard C., Jr. (2 August 2016). "Hemphillian North American Land Mammal Age". Fossil Species of Florida. Florida Museum. Retrieved 7 June 2021.
  16. ↑ Hulbert, Richard C., Jr. (2 August 2016). "Blancan North American Land Mammal Age". Fossil Species of Florida. Florida Museum. Retrieved 7 June 2021.
  17. ↑ Flynn, J., and C.C. Swisher. 1995. Cenozoic South American Land Mammal Ages: correlation to global geochronology. Geochronology Time Scales and Global Stratigraphic Correlation, SEPM Special Publication 54. 317–333.
  18. ↑ Kuhlmann, G.; C.G. Langereis; D. Munsterman; R.-J. van Leeuwen; R. Verreussel; J.E. Meulenkamp; Th.E. Wong (2006). "Integrated chronostratigraphy of the Pliocene-Pleistocene interval and its relation to the regional stratigraphical stages in the southern North Sea region" (PDF). Netherlands Journal of Geosciences. 85: 19–35. doi:10.1017/S0016774600021405. S2CID 62803118.
  19. ↑ Robinson, M.; Dowsett, H.J.; Chandler, M.A. (2008). "Pliocene role in assessing future climate impacts". Eos, Transactions, American Geophysical Union. 89 (49): 501–502. Bibcode:2008EOSTr..89..501R. doi:10.1029/2008eo490001.
  20. ↑ "Solutions: Responding to Climate Change". Climate.Nasa.gov. Retrieved 1 September 2016.
  21. ↑ Dwyer, G.S.; Chandler, M.A. (2009). "Mid-Pliocene sea level and continental ice volume based on coupled benthic Mg/Ca palaeotemperatures and oxygen isotopes". Phil. Trans. Royal Soc. A. 367 (1886): 157–168. Bibcode:2009RSPTA.367..157D. doi:10.1098/rsta.2008.0222. hdl:10161/6586. PMID 18854304. S2CID 3199617.
  22. ↑ Bartoli, G.; et al. (2005). "Final closure of Panama and the onset of northern hemisphere glaciation". Earth Planet. Sci. Lett. 237 (1–2): 3344. Bibcode:2005E&PSL.237...33B. doi:10.1016/j.epsl.2005.06.020.
  23. ↑ Van Andel (1994), p. 226.
  24. ↑ "The Pliocene epoch". University of California Museum of Paleontology. Retrieved 2008-03-25.
  25. ↑ Webb, S. David (1991). "Ecogeography and the Great American Interchange". Paleobiology. 17 (3): 266–280. doi:10.1017/S0094837300010605. JSTOR 2400869.
  26. ↑ Bartoli, G.; Sarnthein, M.; Weinelt, M.; Erlenkeuser, H.; Garbe-Schönberg, D.; Lea, D.W. (August 2005). "Final closure of Panama and the onset of northern hemisphere glaciation". Earth and Planetary Science Letters. 237 (1–2): 33–44. doi:10.1016/j.epsl.2005.06.020.
  27. ↑ Gautier, F., Clauzon, G., Suc, J.P., Cravatte, J., Violanti, D., 1994. Age and duration of the Messinian salinity crisis. C.R. Acad. Sci., Paris (IIA) 318, 1103–1109.
  28. ↑ Krijgsman, W (August 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.
  29. ↑ Gladenkov, Andrey Yu; Oleinik, Anton E; Marincovich, Louie; Barinov, Konstantin B (July 2002). "A refined age for the earliest opening of Bering Strait". Palaeogeography, Palaeoclimatology, Palaeoecology. 183 (3–4): 321–328. doi:10.1016/S0031-0182(02)00249-3.
  30. ↑ Gibert, Jordi Maria de; Martinell, Jordi (January 1995). "Sedimentary substrate andtrace fossil assemblages in marine Pliocene deposits in Northeast Spain". Geobios. 28: 197–206. doi:10.1016/S0016-6995(95)80166-9.
  31. ↑ Deméré, Thomas A. (1983). "The Neogene San Diego basin: a review of the marine Pliocene San Diego formation". Cenozoic Marine Sedimentation, Pacific Margin. Pacific Section,m Society for Sedimentary Geology. Retrieved 7 June 2021.
  32. ↑ Saul, G.; Naish, T.R.; Abbott, S.T.; Carter, R.M. (1 April 1999). "Sedimentary cyclicity in the marine Pliocene-Pleistocene of the Wanganui basin (New Zealand): Sequence stratigraphic motifs characteristic of the past 2.5 m.y.". GSA Bulletin. 111 (4): 524-537. doi:10.1130/0016-7606(1999)111<0524:SCITMP>2.3.CO;2.
  33. ↑ Selli, Raimondo (September 1965). "The Pliocene-Pleistocene boundary in Italian marine sections and its relationship to continental stratigraphies". Progress in Oceanography. 4: 67–86. doi:10.1016/0079-6611(65)90041-8.
  34. ↑ Japsen, Peter; Green, Paul F.; Chalmers, James A.; Bonow, Johan M. (17 May 2018). "Mountains of southernmost Norway: uplifted Miocene peneplains and re-exposed Mesozoic surfaces". Journal of the Geological Society. 175 (5): 721–741. Bibcode:2018JGSoc.175..721J. doi:10.1144/jgs2017-157. S2CID 134575021.
  35. ↑ Lidmar-Bergström, Karna; Olvmo, Mats; Bonow, Johan M. (2017). "The South Swedish Dome: a key structure for identification of peneplains and conclusions on Phanerozoic tectonics of an ancient shield". GFF. 139 (4): 244–259. doi:10.1080/11035897.2017.1364293. S2CID 134300755.
  36. ↑ Mares, Micheal A., ed. (1999). "Miocene". Encyclopedia of Deserts. University of Oaklahoma Press. ISBN 0-8061-3146-2.
  37. ↑ Keigwin, Lloyd D. (1978-10-01). "Pliocene closing of the Isthmus of Panama, based on biostratigraphic evidence from nearby Pacific Ocean and Caribbean Sea cores". Geology (in English). 6 (10): 630–634. doi:10.1130/0091-7613(1978)62.0.CO;2. ISSN 0091-7613.
  38. ↑ Narciso Benítez, Jesús Maíz-Apellániz, and Matilde Canelles et al. (2002). "Evidence for Nearby Supernova Explosions". Phys. Rev. Lett. 88 (8): 081101. arXiv:astro-ph/0201018. Bibcode:2002PhRvL..88h1101B. doi:10.1103/PhysRevLett.88.081101. PMID 11863949. S2CID 41229823.CS1 maint: uses authors parameter (link)
  39. ↑ Katie Pennicott (Feb 13, 2002). "Supernova link to ancient extinction". physicsworld.com. Retrieved 16 July 2012.
  40. ↑ Comins & Kaufmann (2005), p. 359.
  41. ↑ "Researchers consider whether supernovae killed off large ocean animals at dawn of Pleistocene". phys.org (in English).
  42. ↑ "Researchers consider whether supernovae killed off large ocean animals at dawn of Pleistocene". phys.org (in English).
  43. ↑ "Interstellar Iron Found In Antarctic Snow - Astrobiology". astrobiology.com (in English).

Further reading

External links

Lua error in Module:Authority_control at line 1238: attempt to index field 'wikibase' (a nil value).

Retrieved from ‘http://www.encyclopediabritannia.org/index.php?title=Pliocene&oldid=178219’