Piacenzian

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Piacenzian
3.600 – 2.58 Ma
↓
Chronology

The Piacenzian is in the international

age of the Pliocene. It spans the time between 3.6 ± 0.005 Ma and 2.588 ± 0.005 Ma (million years ago). The Piacenzian is after the Zanclean and is followed by the Gelasian (part of the Pleistocene
).

The Piacenzian is roughly coeval with the European land mammal age MN 16, overlaps the late Chapadmalalan and early Uquian South American land mammal age and falls inside the more extensive Blancan North American land mammal age. It also correlates with the Astian, Redonian, Reuverian and Romanian regional stages of Europe, and the Waipipian and Mangapanian stages of New Zealand. Some authorities describe the British Red Crag Formation and Waltonian Stage as late Piacenzian,[6][7] while others regard them as early Pleistocene.[8][9]

Carbon dioxide levels during the Piacenzian were similar to those of today, making this age, with global mean temperature 2–3 °C higher and sea levels about twenty meters higher than today, an important analogue for predictions of the future of our world.[10]

Definition

The Piacenzian was introduced in scientific literature by Swiss stratigrapher Karl Mayer-Eymar in 1858. It is named after the Italian city of Piacenza.

The base of the Piacenzian is at the base of magnetic chronozone C2An (the base of the Gauss chronozone and at the

GSSP for the Piacenzian Stage is at Punta Piccola on Sicily, Italy.[11]

The top of the Piacenzian (the base of the Quaternary System and the Pleistocene Series) is defined

Gauss-Matuyama reversal), and isotopic stage 103. Above this point there are notable extinctions of the calcareous nannofossils: Discoaster pentaradiatus and Discoaster surculus.[12]

Climate

The Piacenzian was the last age before the

solar insolation.[10]

Climate of the Piacenzian would have started as a somewhat wet and warm period in North America occurring just after a brief cooling period of the Zanclean. Deposition of sediments and mollusks of the Piacenzian correspond with the rise in sea level creating the Tamiami Subsea and Jackson Subsea of Florida, Duplin Subsea generally of South Carolina, and Yorktown Subsea of the Outer Banks and inland North Carolina. Dates have been established on the basis of the genera and species of mollusks found.[13]

Origin of the genus Homo

The late Piacenzian may be when the genus Homo developed out of the ancestral genus Australopithecus.[14] While the oldest known fossils unambiguously identified as Homo habilis date to just after the end of the Piacenzian (2.58 Ma), a fossilized jawbone that exhibits traits that are transitional between Australopithecus and Homo habilis was discovered in the Afar Triangle in 2015. The find was made by Ethiopian student Chalachew Seyoum at a site called

savanna as the ancestral environment which shaped the evolution of early Homo and other hominins.[17]

References

Wikimedia Commons has media related to Piacenzian.

Notes

  1. doi:10.1016/0012-821X(96)00109-4
    .
  2. JSTOR 3515337
    . Retrieved 2008-02-11.
  3. ^ "ICS Timescale Chart" (PDF). www.stratigraphy.org.
  4. doi:10.18814/epiiugs/1998/v21i2/003
    . Retrieved 26 December 2020.
  5. doi:10.18814/epiiugs/1998/v21i2/002
    .
  6. ^ "Red Crag Formation". British Geological Survey. Retrieved 5 August 2016.
  7. ^ "Global Chronostratigraphical Correlation Table for the Last 2.7 Million Years. v.2011". University of Cambridge. Retrieved 5 August 2016.
  8. ^ "The Naze citation" (PDF). Sites of Special Scientific Interest. Natural England. Archived from the original (PDF) on 4 March 2016. Retrieved 5 August 2016.
  9. ISBN 978-0-19-96530 6-5
    .
  10. ^
    PMID 32647351
    .
  11. ^ Castradori et al. (1998)
  12. ^ Gadstein et al. (2005), p. 28; Rio et al. (1998)
  13. ISBN 0-8493-1632-4
    .
  14. ^ Pallab Ghosh (4 March 2015). "'First human' discovered in Ethiopia". BBC. Retrieved 22 March 2015.
  15. ^ "Oldest known member of human family found in Ethiopia". New Scientist. 4 March 2015. Retrieved 7 March 2015.
  16. ^ Ghosh, Pallab (4 March 2015). "'First human' discovered in Ethiopia". bbc.co.uk. Retrieved 7 March 2015.
  17. PMID 25739409
    .

Literature

Wikisource has original works on the topic: Cenozoic#Neogene

External links
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