Tournaisian
The Tournaisian is in the ICS geologic timescale the lowest stage or oldest age of the Mississippian, the oldest subsystem of the Carboniferous. The Tournaisian age lasted from 358.9 Ma to 346.7 Ma. It is preceded by the Famennian (the uppermost stage of the Devonian) and is followed by the Viséan. In global stratigraphy, the Tournaisian contains two substages: the Hastarian (lower Tournaisian) and Ivorian (upper Tournaisian). These two substages were originally designated as European regional stages.
| Tournaisian | |||||||||||||||
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Paleogeography of the Tournaisian (350 Ma) | |||||||||||||||
| Chronology | |||||||||||||||
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| 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 | FAD of the conodont Siphonodella sulcata (discovered to have biostratigraphic issues as of 2006). | ||||||||||||||
| Lower boundary GSSP | La Serre, Montagne Noire, France 43.5555°N 3.3573°E | ||||||||||||||
| Lower GSSP ratified | 1990 | ||||||||||||||
| Upper boundary definition | FAD of the benthic foraminifer Eoparastaffella simplex | ||||||||||||||
| Upper boundary GSSP | Pengchong Section, Guangxi, China 24.4333°N 109.4500°E | ||||||||||||||
| Upper GSSP ratified | 2008 | ||||||||||||||
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