GSSP Gelasium / Calabrium

Coordinates: 39 ° 2 ′ 19 ″  N , 17 ° 8 ′ 6 ″  E

GSSP Gelasium / Calabrium​

Italy

The GSSP Gelasium / Calabrium is a stratigraphic reference profile that defines the boundary between the Gelasium and the Calabrium . The profile is located at the locality Vrica about 4 kilometers south of Crotone in Calabria . The limit was dated to 1.806 million years BP .

history

The GSSP ( Engl. Global Boundary Stratotype Section and Point - "global reference profile for determining the levels boundaries") Gelasian / Calabrium (also GSSP Calabrium) for the border Gelasian / Calabrium was organized by the International Commission on Stratigraphy accepted (ICS) in 1983 and Ratified by the International Union of Geological Sciences (IUGS) in 1984 . First scientific descriptions come from 1985 by Aguirre and Pasini as well as by Bassett.

Note: Until June 29th, 2009 the GSSP Gelasian / Calabrian had to be referred to as GSSP Pliocene / Pleistocene, since the Calabrian was the lowest stage of the Pleistocene until then . However, since 2009 the IUGS has used the Gelasian instead of the Calabrian as the lowest stage of the Pleistocene (and thus the Quaternary ).

Description and definition

The Vrica reference profile is composed of three subsegments A, B and C that can easily be correlated with one another. The GSSP is located in the middle sub-segment B. The sediments are of marine origin and 300 meters thick. They consist of dark-gray or blue-gray, epibathyal , fossil-bearing, silty-marl-like clay stones in which several grayish-pink layers of sapropel are inserted. Sandy liners are rare. There are three volcanic ash layers, including the "m" layer. At 0.25 to 0.34 millimeters / year, the sedimentary sequence has a very high rate of accumulation. The slightly northerly dipping sequence is complete and has been correlated bank by bank with the profiles of the deep-sea wells in the Mediterranean ODP 964 , ODP 967 and ODP 975 .

The basis of the Calabrium was defined in this reference profile as follows:

It lies at the lower edge of the mudstone horizon overlying the sapropel layer "e" .

Dating and Correlations

The GSSP Gelasium / Calabrium could be assigned an age of 1.806 million years BP by means of astronomical correlation of the sapropel horizons.

The Gelasian / Calabrian boundary correlates with other stratigraphic schemes as follows:

• Magnetostratigraphy : Magnetostratigraphically, the GSSP Gelasium / Calabrium is 10 meters below the upper limit of the Olduvai polarity subchronic (Chron C 2n ), which was dated 1.77 million years BP.

• Oxygen isotope stratigraphy (δ O ¹⁸ ): The GSSP coincides with the transition from the marine isotope stage (MIS) 65 (interstadial) to 64 (stadial). In the Mediterranean region, this corresponds to the precession-related sapropel layer 176 ( MPRS 176 insolation cycle ).

Gephyrocapsa oceanica

• Biostratigraphy :
  • Foraminifera : Last occurrence (LO) of the planktonic foraminifera Globigerinoides obliquus extremus in the hanging wall of the GSSP. The last occurrence of the taxon Globigerinoides fistulosus, recently dated 1.88 million years BP, is below. Globigerina cariacoensis (22 meters above) and Globigerinoides tenellus appear slightly above. The GSSP is also practically identical to the beginning of the mass occurrence (FCO) of the left-rotating foraminiferous taxon Neogloboquadrina pachyderma (3 meters above). It is located near the upper edge of PL 6 ( Menardella miocenica-Globigerinoides fistulosus interval zone ) or in the middle of MPL 6b or in the lowest section of N 22 .
  • Calcareous nannoplankton : Last occurrence (LO) of the taxon Discoaster brouweri (70 meters below) and Discoaster triradiatus in the lying area of ​​the GSSP, Gephyrocapsa oceanica (Gephyrocapsa of medium size) appears for the first time 26 meters above (just above the sapropel layer "h"). The GSSP lies in the lowest section of NN 19 or in the upper section of CN 13a .
  • Radiolarians : First appearance of Anthocyrtidium angulare at the GSSP and of Pterocorys zancleus just below. Pterocanium prismatium disappears above the GSSP located in the radiolaria zone RN 12 b .
  • Dinoflagellates : The taxon Selenopemphix dionaeacysta disappears slightly above the GSSP in the lower section of the dinoflagellate zone D 21 b .
  • Diatoms : Immediately above the GSSP in the diatom zone NPD 10 , Coscinodiscus pustulatus appears for the last time, slightly below Pyxidicula horridus disappears .
  • Land mammals :
    • In North America ( NALMMZ ): Beginning of the Irvingtonium in Ir 1 : First appearance of Paramylodon harlani and Phenacomys slightly above the GSSP, Megalonyx leptostomus , Platygonus bicalcaratus and Ondatra idahoensis disappeared at about the same time .
    • In South America ( SALMMZ ): The GSSP is in the upper third of the Uquium .
    • In Europe ( ELMMZ ): In the immediate vicinity of the GSSP, the first appearance of Canis etruscus ( wolf event ) at the beginning of the Olivola fauna community of the Villa Franchium .

Sea level

The GSSP Gelasium / Calabrium is located just below the high point between the two regressions Ge 2 and Cala 1 . In the long term, however, the sea ​​level has been subject to a general decline since the Upper Piacenzium .

Other equivalents

In north-western Europe the GSSP Gelasium / Calabrium falls shortly before the upper limit of the Tiglium (Tiglium C5-6), in Great Britain it is in the middle of the Pastonium . In the North Sea region, the beginning of the NSR 13 microfossil zone with the last appearance of the benthic foraminiferous taxa Ammonia beccari and Cassidulina grossa . In North America it corresponds to the middle of Preillinoium I or in California to the lowest wheelerium , in the Russian plain to the end of the Khapry . In the Chinese loess stratigraphy , the upper section of the soil horizon WS 3 was formed . In Australia that began Werrikooium and in New Zealand , the inclined Nukumaruum and Marahauum coming to an end.

climate

A drastic climatic change occurred at the GSSP Gelasium / Calabrium . Using palynological research methods, Combourieu-Nebout u. a. demonstrate the forest vegetation ( palm and cypress plants ) of a subtropical to moderately warm climate (outgoing tiglium) below the GSSP . Above the GSSP, a decline in forest vegetation and a transition to cooler, xeric conditions (desertification - massive occurrence of Artemisia ) (incipient eburonium ) can be observed .

literature

• MB Cita et al: The Calabrian Stage redefined . In: Episodes . tape 31 , no. 4 , 2008, p. 408-419 .
• J. Hardenbol et al: Cenozoic-Mesozoic Biochronostratigraphy . 1998.
• F. Gradstein et al: A Geologic Time Scale 2004 . Cambridge University Press, 2004, ISBN 0-521-78673-8 .
• JG Ogg et al: The Concise Geologic Time Scale . 2008.

Individual evidence

1. ^ E. Aguirre, G. Pasini: The Pliocene – Pleistocene Boundary . In: Episodes . tape 8 , no. 2 , 1985, pp. 116-120 .
2. ^ M. Bassett: Towards a “common language” in stratigraphy . In: Episodes . tape 8 , 1985, pp. 87-92 .
3. ^ SC Finney: Formal definition of the Quaternary System / Period and redefinition of the Pleistocene Series / Epoch . In: Episodes . tape 33 , no. 3 , 2010, p. 159-163 .
4. ↑ G. Pasini, ML Cola Longo: Proposal for the erection of the Santernian / Emilian boundary-stratotype (lower Pliocene) and new data on the Pliocene / Pleistocene boundary stratotype . In: Bollettino della Società Paleontologica Italiana . tape 33 , 1994, pp. 101-120 .
5. ^ D. Rio, J. Backman, I. Raffi: Calcareous nannofossil Biochronology and the Pliocene – Pleistocene Boundary . Ed .: Van Couvering: The Pliocene-Pleistocene boundary: Definition and Worldwide Correlation. Cambridge University Press, 1996, pp. 63-78 .
6. ↑ LJ Lourens: Revised tuning of Ocean Drilling Program Site 964 and KC01B (Mediterranean) and implications for the D18O, tephra, calcareous nannofossil, and geomagnetic reversal chronologies of the past 1.1 Myr . In: Paleoceanography . tape 19 , 2004, pp. 3010 .
7. ↑ LJ Lourens, FJ Hilgen, I. Raffi: Base of large Gephyrocapsa and astronomical calibration of early Pleistocene sapropels in Site 967 and Hole 969D: solving the chronology of the Vrica section (Calabria, Italy) . In: HF Robertson, K. Emeis, C. Richter et al. (Eds.): Proceedings of the Ocean Drilling Program, Scientific Results . tape 160 . College Station, TX (Ocean Drilling Program) 1998, p. 191-198 .
8. ↑ JD A Zijderveld, FJ Hilgen, CG Langereis, PJJM Verhallen, WJ Zachariasse: Integrated magnetostratigraphy and biostratigraphy of the Upper Pliocene-Lower Pleistocene from the Monte Singa and Crotone areas in Calabria (Italy) . In: Earth Planetary Science Letters . tape 107 , 1991, pp. 697-714 .
9. Jump up ↑ LJ Lourens, A. Antonarakou, FJ Hilgen, AAM Van Hoof, C. Vergnaud-Grazzini, W. Zachariasse: Evaluation of the Plio-Pleistocene astronomical timescale . In: Paleoceanography . tape 11 , 1996, pp. 391-413 .
10. ^ N. Combourieu-Nebout, F. Semah, T. Djubiantono: La limite Pliocéne-Pléistocéne: précisions magnétostratigraphiques et climatiques par l'étude sériéé de la coupe-type de Vrica (Crotone - Italie) . In: CR Acad. Sc. Paris . tape 311 , series II, 10, 1990, pp. 851-857 .