Cambrian Stage 3

Cambrian Stage 3
Name formalityInformal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Chronological unitAge
Stratigraphic unitStage
Time span formalityFormal
Lower boundary definitionNot formally defined
Lower boundary definition candidatesFAD of Trilobites
Lower boundary GSSP candidate section(s)None
Upper boundary definitionNot formally defined
Upper boundary definition candidatesFAD of the Trilobites Olenellus or Redlichia
Upper boundary GSSP candidate section(s)None

Cambrian Stage 3 is the still unnamed third stage of the Cambrian. It succeeds Cambrian Stage 2 and precedes Cambrian Stage 4, although neither its base nor top have been formally defined. The plan is for its lower boundary to correspond approximately to the first appearance of trilobites, about 521 million years ago,[2] though the globally asynchronous appearance of trilobites warrants the use of a separate, globally synchronous marker to define the base.[3] The upper boundary and beginning of Cambrian Stage 4 is informally defined as the first appearance of the trilobite genera Olenellus or Redlichia around 514 million years ago.[4]

  1. ^ "Chart/Time Scale". International Commission on Stratigraphy.
  2. ^ Ahlberg, Per; Babcock, Loren E. "Subcommission on Cambrian Stratigraphy Annual Report 2017" (PDF). International Commission on Stratigraphy. Retrieved 14 March 2022.
  3. ^ "International Commission on Stratigraphy".
  4. ^ "GSSP Table - Paleozoic Era". Retrieved 18 November 2012.

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