Ordovician period

(redirected from Ordovician)
Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.
Related to Ordovician: Permian

Ordovician period

a period of the PALAEOZOIC ERA which occurred between 515 and 445 million years ago. Algae, particularly calcareous, reef-building forms, were common as were graptolites, corals and brachiopods. The first armoured fish evolved in the Ordovician.
Mentioned in ?
References in periodicals archive ?
The aim of this paper is (1) to report the occurrence of the earliest cornulitid from the Middle Ordovician of Estonia and (2) to discuss the palaeoecology of encrusting cornulitids.
The oxygen increase during the Ordovician radiation could have made more locations on Earth habitable and "supported more predators in the food chain.
Despite their low regional metamorphic grade, the Late Ordovician to Early Devonian cover strata record multi-phase deformation including episodes of recumbent and upright folding, and thrust, strike-slip and high-angle dip-slip faulting.
Thus far, the Bashituopu oil/gas field with the Carboniferous system as the production layer in the west of the Maigaiti slope and the Hetianhe gas field with the Ordovician carbonatite rock-containing buried hill and Carboniferous system as the production layer in the Mazhatage tectonic belt on the northern border of the eastern Maigaiti slope have been identified.
Single kukersite seams are found in the Lower Ordovician Kunda Stage.
To test the adaptive radiation idea, they analyzed the colony forms of 183 neograptine and diplograptine species that lived before, during or after the Ordovician mass extinction - a total of 9 million years of graptoloid history.
The well will be drilled first as a semi-vertical pilot hole, and then sidetracked as a deviated well with a 450 meter horizontal section through the objective Ordovician reservoir.
Brian O'Cathain, Chief Executive, commented, "The results of this well will be used to high-grade the Ordovician prospect inventory for the Ksar Hadada permit.
They also evaluate the migration of faunas in response to Ordovician climatic changes.
For over 150 years, the succession of the British series and stages had been taken as the de facto global standard in Ordovician stratigraphy.
Two subsurface features in central and southwestern Southern Michigan have been interpreted by some researchers to be astroblemes dating to the Ordovician Period.
Saxon remains committed to two West Texas wildcat wells testing the Pennsylvanian age Wolfcamp and the Ordovician age Ellenberger.

Full browser ?