Ordovician Period: Quick Facts

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Last updated

Oct. 9, 2026

Photos

Ordovician paleogeography

A detailed geologic time scale chart displaying Earth's history from the Hadean Eon over 4.5 billion years ago to the present, organized by eons, eras, periods, epochs, and ages with color-coded columns and corresponding dates in millions of years.

Clusters of dark, rounded living stromatolites cover the sandy shore at Hamlyn Bay, Western Australia, with shallow turquoise water in the background.

Diagram showing the structure of trilete spores: the left image displays a tetrad of four connected spores with a central trilete mark, the center shows a single trilete spore from above with labeled features including lasura and margo, and the right shows a side view with labels for proximal and distal poles, equator, margo, and trilete lasurae.

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Topics

Hirnantian Age fossil Ordovician radiation Ordovician-Silurian extinction Taconic orogeny Lituites Diplograptus Didymograptus Platystrophia Maclurites Silurian Period Devonian Period Cambrian Period Permian Period Carboniferous Period

Key People

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Charles Lapworth

British geologist