182.9 - 174.7 Ma

The definition of this interval in the timescale Ammonite Chrons of Northwest Europe is taken from the following source:

• J. Palfy, P. L. Smith, and J. K. Mortensen. 2000. A U-Pb and 40Ar/39Ar time scale for the Jurassic. Canadian Journal of Earth Sciences 37(6):923-944 view

The bottom age has been interpolated based on the differences between the ages for international timescale boundaries quoted in the source and the currently accepted ages for those boundaries.

There are intervals in 6 timescales which overlap this one. show

• International Chronostratigraphic Timescale: Toarcian age, Early Jurassic epoch
• Mesozoic Subages: Late Toarcian subage, Middle Toarcian subage
• Ammonite Chrons of Northwest Europe: Variabilis chron, Thouarsense chron, Bifrons chron
• Ammonite Chrons of North America: Carlottense chron, Crassicosta chron, Yakounensis chron, Hillebrandti chron, Kanense chron, Planulata chron, Arnioceras arnouldi chron
• Calcareous Nannoplankton Zones: NJ8 zone, NJ5 zone, NJ6 zone, NJ7 zone
• Permian-Jurassic of New Zealand: Kawhia epoch, Ururoan age, Temaikan age, Herangi epoch

This interval is used in the definition of 189 collections

A total of 3230 collections with 13663 occurrences lie within this time span