Ordovician

American  

[awr-duh-vish-uhn] / ˌɔr dəˈvɪʃ ən /

adjective

1. 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.

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noun

1. the Ordovician Period or System.

Ordovician British  

/ ˌɔːdəʊˈvɪʃɪən /

adjective

1. 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

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noun

1. the Ordovician period or rock system

Ordovician Scientific  

/ ôr′də-vĭsh′ən /

1. 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.

2. See Chart at geologic time

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Other Word Forms

• post-Ordovician adjective

Etymology

Origin of Ordovician

1879; after the Ordovices (plural) (< Latin ) an ancient British tribe in N Wales, where rocks characterizing the period were found; -ian

Example Sentences

To understand how this played out, the research team assembled an extensive fossil database spanning two centuries of late Ordovician and early Silurian paleontology.

From Science Daily

The fossils studied came from early relatives of modern clams that lived during the Ordovician Period, a time of rapid ecological expansion when marine life became increasingly mobile, predatory, and parasitic.

From Science Daily

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.

From Salon

The extra oxygen likely contributed to the Great Ordovician Biodiversification Event, when new species rapidly flourished, the researchers said.

From Science Daily

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.

From New York Times