Paleozoic Era · Ordovician Period
Earth 450 Million Years Ago: The Ordovician
Earth 450 million years ago in the Ordovician: rich seas, the first plants on land, and Gondwana drifting over the South Pole towards an ice age.
Spin it in 3D and move through timeMap: Ancient maps: PALEOMAP PaleoDEMs (Scotese & Wright 2018), CC BY 4.0 · Natural Earth.
In the Ordovician, life in the sea diversified enormously, in what is called the Great Ordovician Biodiversification Event: reefs, nautiloids, sea lilies and the first jawless fish. The first land plants, small and moss-like, had appeared by about 470 million years ago.
Gondwana was drifting over the South Pole. Around 445 million years ago an ice sheet spread across what is now the Sahara, sea levels dropped and the seas cooled, causing the end-Ordovician mass extinction, which killed around 85% of marine species.
The Iapetus Ocean was closing as Baltica and Avalonia approached Laurentia, raising the first stages of the Appalachian and Caledonian mountains.
Events of the time
Ice sheet over the Sahara
445 million years ago · North Africa
Scratched rock and glacial deposits in the Sahara show that ice covered North Africa when it lay over the South Pole. The cold and falling seas killed about 85% of marine species.
Which land was under the sea 450 million years ago?
On the map nearest this age (450 million years ago, Late Ordovician), about 41% of today’s land was under the sea at some point, some 58.8 million km². That makes it number 13 of the 80 maps from 535 to 5 million years ago, which run from 2% to 50%. Each map shows the greatest flooding of its stage, so no single moment had quite this much sea.
- Tippecanoe Sea
Middle Ordovician to Early Devonian (approximate) · The centre and east of North America: Ohio, Indiana, Kentucky, Tennessee and the Great Lakes
The second flood over North America’s interior, named after the Tippecanoe sequence of rock layers. The limestone around Cincinnati, packed with brachiopods and corals, formed in it.
Was it under the sea? 23 of 42 cities
| Place today | 450 million years ago |
|---|---|
| Alice Springs, Australia | Shallow sea |
| Bangkok, Thailand | Shallow sea |
| Berlin, Germany | Shallow sea |
| Bismarck, United States | Shallow sea |
| Calgary, Canada | Shallow sea |
| Casper, Wyoming, United States | Shallow sea |
| Chicago, United States | Shallow sea |
| Dallas, United States | Shallow sea |
| Denver, United States | Shallow sea |
| Hays, Kansas, United States | Shallow sea |
| Kansas City, United States | Shallow sea |
| Madrid, Spain | Shallow sea |
| Mexico City, Mexico | Shallow sea |
| Montgomery, Alabama, United States | Shallow sea |
| Moscow, Russia | Shallow sea |
| Novosibirsk, Russia | Shallow sea |
| Paris, France | Shallow sea |
| Regina, Canada | Shallow sea |
| Salt Lake City, United States | Shallow sea |
| Tehran, Iran | Shallow sea |
| Vienna, Austria | Shallow sea |
| Warsaw, Poland | Shallow sea |
| Winnipeg, Canada | Shallow sea |
| Almaty, Kazakhstan | Not modelled |
| Baku, Azerbaijan | Not modelled |
| Beijing, China | Land |
| Budapest, Hungary | Not modelled |
| Cairo, Egypt | Land |
| Delhi, India | Land |
| Hannover, Germany | Land |
| Johannesburg, South Africa | Land |
| Kathmandu, Nepal | Land |
| London, United Kingdom | Land |
| Nairobi, Kenya | Land |
| New York, United States | Land |
| Niamey, Niger | Land |
| Perth, Australia | Land |
| Richmond, Queensland, Australia | Land |
| Riyadh, Saudi Arabia | Land |
| Rome, Italy | Land |
| São Paulo, Brazil | Land |
| Timbuktu, Mali | Land |
4,004 marine fossil sites in the Paleobiology Database are dated closely enough to this map. Of those on today’s land, 99% fall in its shaded sea.
Seas: Ancient seas: PaleoCoastlines v7 (Kocsis & Scotese 2021), CC BY 4.0 · Fossils: Paleobiology Database.
Part of the Paleozoic Era & The Cambrian Explosion.