The world, Middle Ordovician, 470 Ma, Global Paleogeographic Views of Earth History, NAU
The world, Middle Ordovician, 458 Ma, PALEOMAP Project
The world, Late Ordovician, 450 Ma, Global Paleogeographic Views of Earth History, NAU
North America, Early Ordovician, 485 Ma, Paleogeography and Geologic Evolution of North America, NAU
North America, Middle Ordovician, 470 Ma, Paleogeography and Geologic Evolution of North America, NAU
North America, Late Ordovician, 450 Ma, Paleogeography and Geologic Evolution of North America, NAU
North America in the Ordovician Period
North American Ordovician Rocks (purple)
Ordovician, Palæos
Ordovician, Wikipedia
The Ordovician, Paleontology Portal
Geologic Time Table, Seafriends
See general sources above.
Early Ordovician Climate, 480 Ma, PALEOMAP project
Middle and Late Ordovician Climate, 440 Ma, PALEOMAP project
Ordovician radiation, Wikipedia.
Ordovician Life, Palæos
Life of the Ordovician, University of California Museum of Paleontology
The Ordovician Period: The Rise of the Cephalopods, Fossil-Facts-and-Finds.com
Ordovician Fossils, Fossil Museum
Ordovician radiation (or The Great Ordovician Biodiversification Event), another explosion of life after the Cambrian-Ordovician extinctions.
The Avalonia terrane moves north away from Gondwana and the Rheic Ocean widens.
Sea level rises to highest levels know in geologic history. Many landmasses are covered by shallow seas. A great deal of the Earth's sedimentary rock was laid at this time.
The Baltica craton and the Avalonia terrane move toward Laurentia (the North American craton). The Iapetus Ocean shrinks while the Rheic Ocean becomes rapidly larger. Gondwana still covers the southern part of earth.
A volcanic island arc east of Siberia and Baltica will eventually form the Kazakhstania continent block.
The western section of the Iapetus Ocean closes as its crust subducts under a volcanic island arc. Mountains are formed in Laurentia as the two landmasses collide. This was the Taconic orogeny (mountain formation) which formed the basement rocks under what would later become the east coast of North America.
Numerous meteor impacts, especially in the Middle Ordovician, may have been due to an asteroid collision and breakup:
Rock Elm Disturbance impact event in Wisconsin.
Granby crater impact event in what is today Sweden.
Neugrund crater impact event in what is today the Baltic Sea in northern Europe.
Ames crater impact event near Laurentia in what is today Oklahoma.
Kärdla crater impact event in Estonia, Europe.
Tvären crater impact event in Sweden.
Lockne crater impact event in Sweden.
Calvin crater impact event in Michigan.
Large Slate Islands impact event in Canada.
Pilot crater impact event in Canada.
Beginning of the Lachlan orogeny in what is today southeastern Australia.
Beginning of the Alice Springs orogeny in central Australia.
Baltica begins to approach Laurentia. The Iapetus Ocean closes on the east side. Mountains begin to form during the intial phases of the Caledonian orogeny in what is today northern Norway (Finnmarkian phase). This mountain building continues into the Silurian and Devonian Periods.
Avalonia begins to collide with Baltica and the Tornquist Sea disappears (Shelveian Phase or Event).
Glaciers form in Gondwana in what are today South America and Africa. An ice age may have occured at the end of the Ordovician. Sea levels fall.
Ordovician-Silurian extinction event, one of the largest extinction events in earth's history, Wikipedia.
© 2009, Mr. Varner.
