Cambrian Stage 3
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 or top have been formally defined yet. The lower boundary is loosely defined as the first appearance of trilobites which happened around ~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
- ↑ "GSSP Table - Paleozoic Era". Retrieved 18 November 2012.
- ↑ "The 13th International Field Conference of the Cambrian Stage Subdivision Working Group" (PDF). Episodes 31 (4): 440–441.
- ↑ 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 | |||||||||||
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| Cambrian | Ordovician | Silurian | Devonian | Carboniferous | Permian | Triassic | Jurassic | Cretaceous | Paleogene | Neogene | 4ry | |
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