Messinian | |||||||||||
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7.246 – 5.333Ma | |||||||||||
Chronology | |||||||||||
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Formerly part of | TertiaryPeriod/System | ||||||||||
Etymology | |||||||||||
Name formality | Formal | ||||||||||
Usage information | |||||||||||
Celestial body | Earth | ||||||||||
Regional usage | Global (ICS) | ||||||||||
Time scale(s) used | ICS Time Scale | ||||||||||
Definition | |||||||||||
Chronological unit | Age | ||||||||||
Stratigraphic unit | Stage | ||||||||||
Time span formality | Formal | ||||||||||
Lower boundary definition |
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Lower boundary GSSP | Oued Akrech section,Rabat,Morocco 33°56′13″N6°48′45″W / 33.9369°N 6.8125°W /33.9369; -6.8125 | ||||||||||
Lower GSSP ratified | January 2000[4] | ||||||||||
Upper boundary definition | Base of the Thvera magnetic event (C3n.4n), which is only 96 ka (5 precession cycles) younger than the GSSP | ||||||||||
Upper boundary GSSP | Heraclea Minoa section,Heraclea Minoa,Cattolica Eraclea,Sicily, Italy 37°23′30″N13°16′50″E / 37.3917°N 13.2806°E /37.3917; 13.2806 | ||||||||||
Upper GSSP ratified | 2000[5] |
TheMessinian is in thegeologic timescale the lastage or uppermoststage of theMiocene. It spans the time between 7.246 ± 0.005Ma and 5.333 ± 0.005 Ma (million years ago). It follows theTortonian and is followed by theZanclean, the first age of thePliocene.
The Messinian overlaps theTurolianEuropean Land Mammal Mega Zone (more precisely MN 12 and 13) and thePontian Central EuropeanParatethys Stage. It also overlaps the lateHuayquerian and earlyMontehermosanSouth American Land Mammal Ages, and falls inside the more extensiveHemphillianNorth American Land Mammal Age.
During the Messinian, around 6 million years ago, theMessinian salinity crisis took place, which brought about repeated desiccations of theMediterranean Sea.
The Messinian was introduced bySwiss stratigrapher Karl Mayer-Eymar in 1867.[6] Its name comes from the Italian city ofMessina onSicily, where theMessinian evaporite deposit is of the same age.
The base of the Messinian is at the first appearance of theplanktonicforam speciesGloborotalia conomiozea and is stratigraphically in the middle of magnetic chronozone C3Br.1r. TheGlobal Boundary Stratotype Section and Point for the Messinian is located in a section at Oued Akrech, near theMoroccan capitalRabat.[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 theextinction level of the calcareousnanoplankton speciesTriquetrorhabdulus rugosus (the base ofbiozone CN10b) and the first appearance of nanoplanktonCeratolithus acutus.[citation needed]
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: CS1 maint: location missing publisher (link)33°56′13″N6°48′45″W / 33.9369°N 6.8125°W /33.9369; -6.8125