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Ordovician
[awr-duh-vish-uhn]
adjective
noting or pertaining to a geologic period of the Paleozoic Era, from 500 million to 425 million years ago, notable for the advent of fish.
noun
the Ordovician Period or System.
Ordovician
/ ˌɔːəʊˈɪʃɪə /
adjective
of, denoting, or formed in the second period of the Palaeozoic era, between the Cambrian and Silurian periods, which lasted for 45 000 000 years during which marine invertebrates flourished
noun
the Ordovician period or rock system
Ordovician
The second period of the Paleozoic Era, from about 505 to 438 million years ago. During this time most of the Earth's landmasses were gathered in the supercontinent Gondwanaland, located in the Southern Hemisphere. Much of this continent was submerged under shallow seas, and marine invertebrates, including trilobites, brachiopods, graptolites, and conodonts were widespread. The first primitive fishes appeared; some evidence suggests the first land plants may also have appeared at this time. By the end of the Ordovician massive glaciers formed on Gondwanaland, causing sea levels to drop and approximately 60 percent of all known marine invertebrates to become extinct.
See Chart at geologic time
Other 51Թ Forms
- post-Ordovician adjective
51Թ History and Origins
Origin of Ordovician1
51Թ History and Origins
Origin of Ordovician1
Example Sentences
The rings are theorized to have formed 466 million years ago during one of the coldest periods in the planet's history, known as the Ordovician.
The extra oxygen likely contributed to the Great Ordovician Biodiversification Event, when new species rapidly flourished, the researchers said.
The fossils hail from Morocco’s Fezouata Formation, a deposit dating back to the Early Ordovician period, which began around 488 million years ago and spanned nearly 45 million years.
Moreover, this biota was once located very close to the South Pole, revealing the composition of Ordovician southernmost ecosystems.
Speculative studies have suggested that events in Earth's fossil record, such as the Late Ordovician mass extinction, could have been caused by a gamma-ray-burst strike.
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