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The Ordovician (/ ɔːr d ə ˈ v ɪ ʃ i. ə n,-d oʊ-,-ˈ v ɪ ʃ ən / or-də-VISH-ee-ən, -doh-, - VISH-ən) [9] is a geologic period and system, the second of six periods of the Paleozoic Era, and the second of twelve periods of the Phanerozoic Eon.
The Hirnantian glaciation, also known as the Andean-Saharan glaciation, Early Paleozoic Ice Age (EPIA), [1] the Early Paleozoic Icehouse, [2] the Late Ordovician glaciation, or the end-Ordovician glaciation, occurred during the Paleozoic from approximately 460 Ma to around 420 Ma, during the Late Ordovician and the Silurian period.
The Late Ordovician is the third and final epoch of the Ordovician period, lasting 15.1 million years and spanning from around 458.2 to 443.1 million years ago. [ 4 ] [ 5 ] The rocks associated with this epoch are referred to as the Upper Ordovician Series.
It existed as a positive topographic area during late Ordovician through the Devonian period which stretched from northern Alabama northeastward to the southeastern tip of Ontario. Fossils from the Ordovician are commonplace in the geologic formations which make up the Cincinnati Arch and are commonly studied along man made roadcuts.
In fact, the Hirnantian (also known as the End Ordovician and the Ordovician-Silurian) mass extinction event represents the second largest such event in geologic history. Approximately 85% of marine (sea-dwelling) species died. Only the End-Permian mass extinction was larger. Unlike many smaller extinction events, however, the long-term ...
The St. Peter Sandstone is an Ordovician geological formation.It belongs to the Chazyan stage of the Champlainian series in North American regional stratigraphy, equivalent to the late Darriwilian global stage.
More recently, a World Ortelius map sold for £4,000 (about $5,000) at an auction in 2012. These maps are celebrated for their artistry and the way they reflect the geographical knowledge of the ...
The Ordovician Martinsburg Formation (Om) is a mapped bedrock unit in Pennsylvania, New Jersey, Maryland, Virginia, and West Virginia.It is named for the town of Martinsburg, West Virginia for which it was first described.