Lower Ordovician

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Lower Ordovician

[′lō·ər ‚ȯr·də′vish·ən]
(geology)
The earliest epoch of the Ordovician period of geologic time, extending from about 490- to 460,000,000 years ago.
References in periodicals archive ?
Le modele des biofacies a Trilobites: un test dans I'Ordovicien inferieur de l'Anti-Atlas, Maroc [The trilobite biofacies model: a test in the Early Ordovician of the Anti-Atlas, Morocco].
Younis Baqi, Department of Chemistry, College of Science); (4) Diagnosis and reservoir quality evaluation of middle Cambrian to early Ordovician clastic hydrocarbon reservoirs in Oman interior sedimentary basin (Dr.
Fourth: "Subsequent Mutations and the Quality of the Oil Reservoirs of the Middle Cambrian Rocks till early Ordovician Period in Oman" Principal Researcher, Dr.
The term was coined in 1980 to indicate the system of carbonates and related shallow-water siliciclastics that were deposited on and around the Laurentian continent--the northern fragment as Pangaea broke up--during the Cambrian, Early Ordovician, and earliest Middle Ordovician nearly 500 million years ago.
1992) in maintaining that Avalonia was part of Gondwana throughout this time interval until the Early Ordovician, whereas Landing and co-workers maintain that Avalonia was a separate microcontinent at different paleolatitudes during the late Neoproterozoic and Cambrian.
Briggs said: "The early Ordovician was a critical moment when massive diversification takes off, but we were only seeing a small piece of the picture that was based almost exclusively on the shelly fossil record.
The Estonian black argillites and mudstones were formed during the period of time from Late Cambrian (Furongian) to Early Ordovician (Tremadoc).
Palaeomagnetic data place the Baltica Palaeocontinent at the temperate southern latitudes in the Early Ordovician, on the eastern side of the Iapetus Ocean.
Appalachian Basin play targets the early Ordovician age, Trenton-Black River
The Boundary Mountains terrane moved southeastward and became amalgamated with the Gander margin during Late Cambrian to Early Ordovician, the Penobscottian (Penobscot) orogeny.
Fish, the first animals with backbones, had appeared by the early Ordovician period, some 500 million years ago, and they remained the only vertebrates until around 360 million years ago.