Late Jurassic

  (Redirected from Upper Jurassic)

The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.[2]

Late/Upper Jurassic
163.5 ± 1.0 – ~145.0 Ma
Chronology
Etymology
Chronostratigraphic nameUpper Jurassic
Geochronological nameLate Jurassic
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitEpoch
Stratigraphic unitSeries
Time span formalityFormal
Lower boundary definitionNot formally defined
Lower boundary definition candidatesHorizon of the Ammonite Cardioceras redcliffense.
Lower boundary GSSP candidate section(s)
Upper boundary definitionNot formally defined
Upper boundary definition candidates
Upper boundary GSSP candidate section(s)None

In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age.[3] In the past, Malm was also used to indicate the unit of geological time, but this usage is now discouraged to make a clear distinction between lithostratigraphic and geochronologic/chronostratigraphic units.

SubdivisionsEdit

The Late Jurassic is divided into three ages, which correspond with the three (faunal) stages of Upper Jurassic rock:

  Tithonian (152.1 ± 0.9 – 145.0 ± 0.8 Ma)
  Kimmeridgian (157.3 ± 1.0 – 152.1 ± 0.9 Ma)
  Oxfordian (163.5 ± 1.0 – 157.3 ± 1.0 Ma)

PaleogeographyEdit

During the Late Jurassic Epoch, Pangaea broke up into two supercontinents, Laurasia to the north, and Gondwana to the south. The result of this break-up was the spawning of the Atlantic Ocean. However, at this time, the Atlantic Ocean was relatively narrow.

Life forms of the epochEdit

This epoch is well known for many famous types of dinosaurs, such as the sauropods, the theropods, the thyreophorans, and the ornithopods. Other animals, such as crocodiles and the first birds, appeared in the Jurassic. Listed here are only a few of the many Jurassic animals:

ReferencesEdit

  1. ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy.
  2. ^ Owen 1987.
  3. ^ Gradstein, F.M.; Ogg, J.G.; Schmitz, M.D.; Ogg, G.M. (editors) (2012). The Geologic Timescale 2012 (volume 1). Elsevier. p. 744. ISBN 978-0-44-459390-0.CS1 maint: uses authors parameter (link)