Ordovician


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Related to Ordovician: Permian

Ordovician

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

Ordovician

[‚ȯrd·ə′vish·ən]
(geology)
The second period of the Paleozoic era, above the Cambrian and below the Silurian, from approximately 500 million to 440 million years ago.
References in periodicals archive ?
During the Ordovician Baltica drifted from the temperate climatic zone into the subtropical realm (Cocks & Torsvik 2005; Torsvik et al.
While oxygen was just 14 percent of the air in the middle of the Ordovician period, in a space of about 10 million years it jumped dramatically; it constituted almost a quarter of the atmosphere in the late part of that period.
Well-drilling exploration has revealed the absence of the Middle Ordovician Yijianfang and Upper Ordovician Tumuxiuke formations in the central Tarim uplift between the Mid-Lower Ordovician Yingshan and the Upper Ordovician Lianglitage formations of the Bachu uplift (Yang et al.
The Ordovician Mossen and Fjacka black shales and contemporaneous shallow shelf sediments do not reveal signs of increased bioproductivity, such as chert concretions and barite found in the limestone of the Raikkiila Stage correlative with the Dobele Formation.
Almost immediately following the Ordovician mass extinction, new neograptine species proliferated, as expected.
They persuasively argue for a unified existence of Avalonia as a single terrane during the Ordovician, rather than as independent West and East Avalonian terranes.
In this paper we aim to provide an up-to-date compilation of the Ordovician timescale as it is used in Estonia.
Toward the end of the Ordovician Period about 444 million years ago, life was still largely confined to Earth's oceans and seas, but it still had a lot of diversity, including the appearance of the first known bony vertebrates.
The acquisition of these additional permit areas are the result of a technical evaluation of drilling programs carried out on the Bannock Creek property which have confirmed Saturns exploration model of Ordovician Red River source rock with large structural traps north of the Potash Restriction Zone, in the Oil Triangle.
Eastern Australia has been affected by the Ross - Delamerian (520-500 Ma), an Early Ordovician (475-450 Ma), Benambran (440-420 Ma), Tabberabberan (410-370 Ma), Kanimblan (360-320 Ma) and Hunter-Bowen (Permian) Orogenies.

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