Calabrian (stage)

Coordinates: 39°02′19″N 17°08′06″E / 39.03861°N 17.13500°E / 39.03861; 17.13500
Source: Wikipedia, the free encyclopedia.
Calabrian
1.80 – 0.774 Ma
↓
Chronology

Calabrian is a subdivision of the

Epoch of the geologic time scale, defined as 1.8 Ma—774,000 years ago ± 5,000 years, a period of ~1.026
million years.

The end of the stage is defined by the last

faunal stage
primarily based on mollusk fossils. It has become the second geologic age in the Early Pleistocene.

History of the definition of the Calabrian

Because sea shells are much more abundant as fossils, 19th- and early-20th-century geo-scientists used the plentiful and well-differentiable

southern Italy. However, it was discovered that the original type section was discontinuous at that point and that the base of the Calabrian Stage as defined by fauna assemblages extended to earlier levels within the Pleistocene. A new type section was chosen, several miles from the original one, at Vrica, 4 km south of Crotone in Calabria, southern Italy. Analysis of strontium and oxygen isotopes as well as of planktonic foraminifera has confirmed the viability of the current type section. The 27th International Geological Congress in Moscow in 1984 formally ratified the type section. The starting date was originally thought to be about 1.65 million years ago, but has been recalculated as 1.806 Mya.[6]

Present formal definition

The Global Boundary Stratotype Section and Point,

GSSP, for the former[7] start of the Pleistocene is in a reference section at Vrica, 4 km south of Crotone in Calabria, Southern Italy, a location whose exact dating has recently been confirmed by analysis of strontium and oxygen isotopes as well as by planktonic foraminifera.[8]

The beginning of the Calabrian hence is defined as: Just above top of magnetic polarity chronozone C2n (Olduvai) and the extinction level of calcareous nannofossil Discoaster brouweri (base Zone CN13). Above the boundary are the lowest occurrence of calcareous nannofossil medium Gephyrocapsa spp. and the extinction level of the planktonic foraminifer Globigerinoides extremus.[6]

The end of the Calabrian is defined as the Brunhes–Matuyama magnetic reversal event.[8][9]

See also

Notes

  1. ^ Cohen, K. M.; Finney, S. C.; Gibbard, P. L.; Fan, J.-X. (January 2020). "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. Retrieved 23 February 2020.
  2. doi:10.18814/epiiugs/2018/018016
    . Retrieved 11 November 2019.
  3. hdl:10261/250367
    . Retrieved 26 December 2020.
  4. ^ "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 26 December 2020.
  5. ^ A chronology of Pliocene sea-level fluctuations, U.S. Atlantic Coastal Plain: Quaternary Science Reviews, v. 10, p. 163–174.
  6. ^ a b Calabrian (stage) at the GeoWhen database
  7. S2CID 54629809. abstract
  8. ^ a b 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;
  9. doi:10.18814/epiiugs/2008/v31i4/006
    .

References

39°02′19″N 17°08′06″E / 39.03861°N 17.13500°E / 39.03861; 17.13500

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