Early Ordovician
| Early/Lower Ordovician | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
A map of Earth as it appeared 480 million years ago during the Early Ordovician Epoch, Tremadocian Age | |||||||||||
| Chronology | |||||||||||
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| Etymology | |||||||||||
| Chronostratigraphic name | Lower Ordovician | ||||||||||
| Geochronological name | Early Ordovician | ||||||||||
| Name formality | Formal | ||||||||||
| Usage information | |||||||||||
| Celestial body | Earth | ||||||||||
| Regional usage | Global (ICS) | ||||||||||
| Time scale(s) used | ICS Time Scale | ||||||||||
| Definition | |||||||||||
| Chronological unit | Epoch | ||||||||||
| Stratigraphic unit | Series | ||||||||||
| Time span formality | Formal | ||||||||||
| Lower boundary definition | FAD of the conodont Iapetognathus fluctivagus. | ||||||||||
| Lower boundary GSSP | Greenpoint section, Green Point, Newfoundland, Canada 49°40′58″N 57°57′55″W / 49.6829°N 57.9653°W | ||||||||||
| Lower GSSP ratified | 2000 | ||||||||||
| Upper boundary definition | FAD of the conodont Baltoniodus triangularis | ||||||||||
| Upper boundary GSSP | Huanghuachang section, Huanghuachang, Yichang, China 30°51′38″N 110°22′26″E / 30.8605°N 110.3740°E | ||||||||||
| Upper GSSP ratified | 2007 | ||||||||||
| Atmospheric and climatic data | |||||||||||
| Mean atmospheric O2 content | c. 11.5 vol % (55 % of modern) | ||||||||||
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The Early Ordovician is the first epoch of the Ordovician period, corresponding to the Lower Ordovician series of the Ordovician system. It began after the Age 10 of the Furongian epoch of the Cambrian and lasted from 486.85 to 471.3 million years ago, until the Dapingian age of the Middle Ordovician. It includes Tremadocian and Floian ages.