Messinian

Sixth and last age of the Miocene Epoch, about 7 to 5 million years ago From Wikipedia, the free encyclopedia

The Messinian is in the geologic timescale the last age or uppermost stage of the Miocene. It spans the time between 7.246 ± 0.005 Ma and 5.333 ± 0.005 Ma (million years ago). It follows the Tortonian and is followed by the Zanclean, the first age of the Pliocene.

Quick Facts Chronology, Formerly part of ...
Messinian
7.246 – 5.333 Ma
Chronology
Formerly part ofTertiary Period/System
Etymology
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitAge
Stratigraphic unitStage
Time span formalityFormal
Lower boundary definition
Lower boundary GSSPOued Akrech section, Rabat, Morocco
33.9369°N 6.8125°W / 33.9369; -6.8125
Lower GSSP ratifiedJanuary 2000[4]
Upper boundary definitionBase of the Thvera magnetic event (C3n.4n), which is only 96 ka (5 precession cycles) younger than the GSSP
Upper boundary GSSPHeraclea Minoa section, Heraclea Minoa, Cattolica Eraclea, Sicily, Italy
37.3917°N 13.2806°E / 37.3917; 13.2806
Upper GSSP ratified2000[5]
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The Messinian overlaps the Turolian European Land Mammal Mega Zone (more precisely MN 12 and 13) and the Pontian Central European Paratethys Stage. It also overlaps the late Huayquerian and early Montehermosan South American Land Mammal Ages, and falls inside the more extensive Hemphillian North American Land Mammal Age.

During the Messinian, around 6 million years ago, the Messinian salinity crisis took place, which brought about repeated desiccations of the Mediterranean Sea.

Definition

Thumb
Messinian gypsum and clay deposits in the Sorbas basin near Sorbas, southern Spain. Evaporite deposits of Messinian age are common throughout the Mediterranean.

The Messinian was introduced by Swiss stratigrapher Karl Mayer-Eymar in 1867.[6] Its name comes from the Italian city of Messina on Sicily, where the Messinian evaporite deposit is of the same age.

The base of the Messinian is at the first appearance of the planktonic foram species Globorotalia conomiozea and is stratigraphically in the middle of magnetic chronozone C3Br.1r. The Global Boundary Stratotype Section and Point for the Messinian is located in a section at Oued Akrech, near the Moroccan capital Rabat.[7]

The top of the Messinian (the base of the Zanclean Stage and Pliocene Series) lies with the top of magnetic chronozone Cr3 (about 100,000 years before the Thvera normal subchronozone C3n.4n). The top is also close to the extinction level of the calcareous nanoplankton species Triquetrorhabdulus rugosus (the base of biozone CN10b) and the first appearance of nanoplankton Ceratolithus acutus.[citation needed]

References

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