GSSP Pliocene / Pleistocene

Coordinates: 37 ° 8 ′ 49 ″  N , 14 ° 12 ′ 13 ″  E

GSSP Pliocene / Pleistocene​

Italy

The GSSP Pliocene / Pleistocene is a stratigraphic reference profile that defines the boundary between the Piacenzian and Gelasian . The profile is located on Monte San Nicola near Gela in Sicily . The limit was dated 2.588 million years BP .

history

The GSSP ( Engl. Global Boundary Stratotype Section and Point - global reference profile for determining the levels boundaries) Pliocene / Pleistocene (also GSSP Gelasian) for the border Pliocene / Pleistocene was organized by the International Commission on Stratigraphy ratified (ICS) in August 1996 and scientifically by Rio et al. 1998 described. The final decision to set this GSSP as the lower limit of the Pleistocene and thus the Quaternary was made on June 29, 2009 by the International Union of Geological Sciences (IUGS).

Description and definition

The sedimentary sequence belonging to the Monte Narbone Formation on Monte San Nicola near Gela in Sicily contains a bundle of six sapropel horizons that can be found throughout the Mediterranean . The sapropeles can be correlated with precession cycles. In English they are therefore referred to as Mediterranean precession related sapropels (precession related sapropels ) or MPRS for short . They are also known as insolation-related cycles or i-cycles for short , since the sapropeles with marls assume a cyclical, astronomically controlled alternating position.

The basis of the gelasia was defined as follows:

It lies on the upper edge of Sapropel MPRS 250 (the so-called Nicola layer) and forms the boundary to the overlying, homogeneous marl band .

In the stratigraphic profile on Monte San Nicola this corresponds to meters 62.

Dating and Correlations

The Piacenzium / Gelasium boundary was dated to 2.588 million years BP using astronomical cycles such as the two eccentricity cycles of 100,000 and 413,000 years, the earth axis inclination cycle of 41,000 years and the precession cycle of 21,000 years, and using an astronomical calibration procedure (such as ATNTS 2004 ).

The boundary correlates with other stratigraphic schemes as follows:

• Magnetostratigraphy : 1 meter below the Gauss - Matuyama polarity reversal (in Singa profile), which is therefore an excellent distinguishing feature of the boundary
• Oxygen isotope stratigraphy (δ O ¹⁸ ): Within the marine isotope stage (MIS) 103 (corresponds to an interglacial), about 60,000 years below the prominent stage 100 (glacial).
• Biostratigraphy :
  • Foraminifera : Last occurrence of the planktonic taxa Globorotalia bononiensis and Neogloboquadrina atlantica 140,000 years above the border. In the Mediterranean and the Atlantic, this corresponds to the end of isotope stage 96 (glacial). First appearance of Globorotalia truncatolinoides in the Pacific region. The border is thus located in the upper section of the PI 5 foraminiferous zone or in the upper section of MPL 5a . It also separates NN 20 from NN21 .
  • Calcareous nannoplankton : Last appearance of Discoaster pentaradiatus and Discoaster surculus 80,000 years above the limit, ie during stage 99 (interglacial). The limit is thus at the upper limit of the NN 16 nannoplankton zone (or near the upper limit of CN 12b ).
  • Radiolaria : Approximate correlation with the last occurrence of Stichocorys peregrina (slightly below) or with the end of the Pterocanium prismaticum zone . Beginning of the radiolarian zone RN 12 a and the first appearance of the taxa Theocorythium trachelium trachelium , Lamprocyrtis neoheteroporus and Cycladophora davisiana .
  • Dinoflagellates : First occurrence of Spiniferites pachyderma and last occurrence of Invertocysta tabulata (and thus beginning of the dinoflagellate zone D 21 b ) 80,000 years above the limit.
  • Diatoms : Approximate correlation with the first occurrence of Nitschia joussaea in low latitudes and the last occurrence of Neodenticula kamtschatica in the North Pacific and in high latitudes (lies slightly below). First appearance of neodenticula seminae and beginning of the diatom zone NPD 9 .
  • Land mammals :
    • In North America ( NALMMZ ): first appearance of Glossotherium chapadmalense and Mictomys vetus and beginning of Blancum Bl 5 . Last appearance of Dipoides rexroadensis , Ogmodontomys poaphagus , Pliopotamys, and Pliolemmus .
    • In Europe ( ELMMZ ): Beginning of the Upper Villa Franchium : Large migrations of elephants and horses.

Other equivalents

The GSSP Pliocene / Pleistocene correlates with a worldwide regression phase at the end of the Piacenzian.

In north-western Europe the pretiglium begins , which in Great Britain corresponds to the beginning of the middle preludhamium and in North America to the beginning of preillinoium K (in California the middle repettium ). On the Russian level, the Verkhodon (or Os'kinovium ) begins just below the GSSP. In the Chinese loess stratigraphy the important soil horizon RS was formed . In Australian stratigraphy, the GSSP is in the middle of the Yatalum , in New Zealand in the middle of the Mangapanium .

meaning

The GSSP Pliocene / Pleistocene is very close to the Gauss-Matuyama polarity reversal of the earth's magnetic field. In its immediate vicinity, however, a significant climatic event took place, which is not only noticeable in marine sediments, but also in continental deposits. For example, loess sedimentation began in China. In Europe , the cool pretiglium preceding the Tiglium can be separated palynologically . In the case of land mammals in Eurasia, there were larger, radiative migratory movements such as B. in the elephants ( Archidiskodon gromovi ) and horses ( Equus livenzovensis ).

All of this speaks for a clear deterioration in the climate (cooling) with receding of the forest vegetation and the beginning of the savannah formation , which is also reflected in a faunistic change - in addition to Hipparion, for example, the forest dwellers Mammuthus , Tapirus , Sus minor and Ursus minimus disappeared . Anancus arvernensis , Archidiskodon gromovi , Eucladoceros falconeri , Equus livenzovenzis , Gazella borbonica , Odobaenus and Choneziphius appeared in their place . In addition to Equus Rhinoceros , Elephas hysudricus and Stegodon insignis appear on the Indian subcontinent .

literature

• J. Hardenbol, inter alia: Cenozoic-Mesozoic Biochronostratigraphy . 1998.
• F. Gradstein, among others: A Geologic Time Scale 2004 . Cambridge University Press, 2004, ISBN 0-521-78673-8 .
• JG Ogg, among others: The Concise Geologic Time Scale . 2008.

Individual evidence

1. ^ ^{A b} D. Rio, R. Sprovieri, D. Castradori, E. Di Stefano: The Gelasian Stage (Upper Pliocene): a new unit of the global standard chronostratigraphic scale . In: Episodes . tape 21 , 1998, pp. 82-87 .
2. ^ FJ Hilgen: Astronomical calibration of Gauss to Matuyama sapropels in the Mediterranean and implication for the Geomagnetic Polarity Time Scale . In: Earth and Planetary Science Letters . tape 104 , 1991, pp. 226-244 .
3. ^ CG Langereis, among others: Steadying the rates . In: Nature . tape 369 , 1994, pp. 615 .
4. ↑ LJ Lourens, inter alia: Late Pliocene to early Pleistocene astronomically forced sea surface productivity and temperature variations in the Mediterranean . In: Marine Micropaleontology . tape 19 , 1992, pp. 49-78 .
5. ↑ MB Cita, D. Rio, R. Sprovieri: The Pliocene Series: Chronology of the type Mediterranean record and standard chronostratigraphy . Ed .: JH Wrenn, J.-P. Suc, SAG Leroy, The Pliocene: Time of Change. American Association of Stratigraphic Palynologists Foundation. Dallas, Texas 1999, pp. 49-63 .
6. ^ G. Kukla, Z. Han: Loess stratigraphy in central China . In: Palaeogeography, Palaeoclimatology, Palaeoecology . tape 72 , 1989, pp. 200-225 .
7. ^ WH Zagwijn: The Pliocene – Pleistocene boundary in western and southern Europe . In: Boreas . tape 3 , 1974, p. 75-97 .
8. ^ F. Masini, D. Torre: Large Mammal dispersal events at the beginning of the Late Villafranchian . Ed .: EH Lindsay, et al., European Neogene Mammal Chronology. Plenum Press, New York 1990, pp. 131-138 .
9. ↑ A. Azzaroli, among others: Late Pliocene to Early-Mid Pleistocene Mammals in Eurasia: Faunal succession and dispersal events . In: Palaeogeography, Palaeoclimatology, Palaeoecology . tape 66 , 1988, pp. 77-100 .