Cambrian Stage 3

Key events in the Cambrian
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Fortunian
"Stage 2"
"Stage 3"
"Stage 4"
"Stage 5"
Drumian
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Jiangshanian
"Stage 10"
 
 
 
 
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Baykonurian glaciation
Baykonurian glaciation
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Orsten Fauna
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Burgess Shale
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Kaili biota
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Archaeocyatha extinction
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Emu Bay Shale
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Sirius Passet biota
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Chengjiang biota
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First Trilobites
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SSF diversification, first brachiopods & archaeocyatha
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First halkieriids, mollusсs, hyoliths SSF
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Treptichnus pedum trace
Large negative peak δ 13Ccarb excursion
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First Cloudina & Namacalathus mineral tubular fossils
Stratigraphic scale of the ICS subdivisions and Precambrian/Cambrian boundary.

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 lower boundary is loosely defined as the first appearance of trilobites about 521 million years ago. 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.[1]

Naming

The International Commission on Stratigraphy has not officially named the 3rd stage of the Cambrian. Sometimes this stage is referred to as "Atdabanian" which is used by geologists working in Siberia.[2]

Biostratigraphy

The oldest trilobites known is Lemdadella which appears at the beginning of the Fallotaspis zone.[3]

References

  1. ↑ "GSSP Table - Paleozoic Era". Retrieved 18 November 2012.
  2. ↑ "The 13th International Field Conference of the Cambrian Stage Subdivision Working Group" (PDF). Episodes. 31 (4): 440–441.
  3. ↑ Yuan, J.L.; Zhu, X.J.; Lin, J.P.; Zhu, M.Y. (22 September 2011). "Tentative correlation of Cambrian Series 2 between South China and other continents" (PDF). Bulletin of Geosciences: 397–404. doi:10.3140/bull.geosci.1274. Retrieved 23 November 2012.
Preceded by Proterozoic Eon Phanerozoic Eon
Paleozoic Era Mesozoic Era Cenozoic Era
Cambrian Ordovician Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous Paleogene Neogene 4ry
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