Oxfordian Stage

Oxfordian Stage

      lowest of the three divisions of the Upper Jurassic Series, representing all rocks formed worldwide during the Oxfordian Age, which occurred between 161.2 million and 155.7 million years ago during the Jurassic Period. (Some researchers have proposed a longer span for this stage that extends into more recent time.) The Oxfordian Stage underlies the Kimmeridgian Stage and overlies the Callovian Stage of the Middle Jurassic Series.

      The name for this stage is derived from Oxford, Oxfordshire, England. The stage includes up to 90 metres (295 feet) of strata, including portions of the Oxford Clay and the Corallian Beds. The Oxfordian is divided into the Lower, Middle, and Upper Oxfordian, each of which is further subdivided into zones. In Europe there are seven standard ammonite (ammonoid) biozones (biozone), with two (the Mariae and Cordatum) in the Lower Oxfordian, two (the Plicatilis and Transversarium) in the Middle Oxfordian, and three (the Bifurcatum, Bimammatum, and Planula) in the Upper Oxfordian. Outside of Europe the distribution of ammonites and other fossils used in correlations is often patchy because of unsuitable habitats during the Oxfordian and deformation of the strata after deposition. In addition, because of the limited geographic range of many species, it is difficult to correlate strata between regions of the world. In North America a number of different zones have been established for different areas, but gaps within the sequences prevent the zones from spanning the entire Oxfordian. In Asia and the southern Pacific there are fewer established zones, and their exact placement in relationship to global correlations is unclear.

Carol Marie Tang
 

* * *


Universalium. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Oxfordian (stage) — System Series Stage Age (Ma) Cretaceous Lower Berriasian younger Jurassic Upper Tith …   Wikipedia

  • Oxfordian stage — The Oxfordian stage is the first stage of the Late Jurassic Epoch. It spans the time between 161.2 ± 4 Ma and 155.7 ± 4 Ma (million years ago).The stage takes its name from the city of Oxford in England.Vertebrate FaunaOrnithischiansInertebrate… …   Wikipedia

  • Oxfordian — may refer to: Oxfordian theory of Shakespeare authorship, view that Edward de Vere wrote under Shakespeare s name Oxfordian (stage), a geological time interval This disambiguation page lists articles associated with the same title. If an …   Wikipedia

  • Oxfordian theory of Shakespeare authorship — Edward de Vere, the 17th Earl of Oxford, is the most popular alternative candidate for the author behind the alleged pseudonym, Shakespeare. Unknown artist after lost original, 1575; National Portrait Gallery, London. The Oxfordian theory of… …   Wikipedia

  • Oxfordian theory — The Oxfordian theory of Shakespearean authorship holds that Edward de Vere, 17th Earl of Oxford (1550 1604), wrote the plays and poems attributed to William Shakespeare of Stratford upon Avon. While mainstream scholars who take the Stratfordian… …   Wikipedia

  • Callovian Stage — ▪ geochronology       uppermost of the four divisions of the Middle Jurassic Series, representing all rocks formed worldwide during the Callovian Age, which occurred between 164.7 million and 161.2 million years ago during the Jurassic Period.… …   Universalium

  • Kimmeridgian Stage — ▪ geology       middle of the three divisions of the Upper Jurassic Series, representing all rocks formed worldwide during the Kimmeridgian Age, which occurred between 155.7 million and 150.8 million years ago during the Jurassic Period. (Some… …   Universalium

  • Jurassic Period — Interval of geologic time, 206–144 million years ago, that is one of the three major divisions of the Mesozoic Era, preceded by the Triassic Period and followed by the Cretaceous. During the Jurassic, Pangea began to break up into the present day …   Universalium

  • Morrison Formation — ▪ geology       series of sedimentary (sedimentary rock) rocks deposited during the Jurassic Period in western North America, from Montana to New Mexico. The Morrison Formation is famous for its dinosaur fossils, which have been collected for… …   Universalium

  • Kimmeridgian — The Kimmeridgian is a stage of the Late Jurassic Epoch. It spans the time between 155.7 ± 4 Ma and 150.8 ± 4 Ma (million years ago). The Kimmeridgian stage follows the Oxfordian stage and precedes the Tithonian stage.The stage takes its name from …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”