Cambrian Stage 3
| Cambrian Stage 3 | ||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chronology | ||||||||||||||||||||||||||||||||||||||
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| Etymology | ||||||||||||||||||||||||||||||||||||||
| Name formality | Informal | |||||||||||||||||||||||||||||||||||||
| Usage information | ||||||||||||||||||||||||||||||||||||||
| Celestial body | Earth | |||||||||||||||||||||||||||||||||||||
| Regional usage | Global (ICS) | |||||||||||||||||||||||||||||||||||||
| Time scale(s) used | ICS Time Scale | |||||||||||||||||||||||||||||||||||||
| Definition | ||||||||||||||||||||||||||||||||||||||
| Chronological unit | Age | |||||||||||||||||||||||||||||||||||||
| Stratigraphic unit | Stage | |||||||||||||||||||||||||||||||||||||
| Time span formality | Formal | |||||||||||||||||||||||||||||||||||||
| Lower boundary definition | Not formally defined | |||||||||||||||||||||||||||||||||||||
| Lower boundary definition candidates | FADofTrilobites | |||||||||||||||||||||||||||||||||||||
| Lower boundary GSSP candidate section(s) | None | |||||||||||||||||||||||||||||||||||||
| Upper boundary definition | Not formally defined | |||||||||||||||||||||||||||||||||||||
| Upper boundary definition candidates | FAD of theTrilobitesOlenellusorRedlichia | |||||||||||||||||||||||||||||||||||||
| Upper boundary GSSP candidate section(s) | None | |||||||||||||||||||||||||||||||||||||
Cambrian Stage 3is the still unnamed third stage of theCambrian.It succeedsCambrian Stage 2and precedesCambrian 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 oftrilobites,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 ofCambrian Stage 4is informally defined as the first appearance of thetrilobitegeneraOlenellusorRedlichiaaround 514 million years ago.[4]
Naming[edit]
TheInternational Commission on Stratigraphyhas not officially named the 3rd stage of the Cambrian. The stage approximately corresponds to the "Atdabanian",which is used by geologists working inSiberia.[5]
Biostratigraphy[edit]
The oldesttrilobiteknown isLemdadellawhich appears at the beginning of theFallotaspiszone.[6]TheCambrian radiationof animal phyla ends here, after the diversification and origination ofarthropods,molluscs,lophophorates,chordates(includingvertebrates) among others.[7]
References[edit]
- Zhang (2017). "Challenges in defining the base of Cambrian Series 2 and Stage 3".Earth-Science Reviews.172:124–139.Bibcode:2017ESRv..172..124Z.doi:10.1016/j.earscirev.2017.07.017.
- ^"Chart/Time Scale".stratigraphy.org.International Commission on Stratigraphy.
- ^Ahlberg, Per; Babcock, Loren E."Subcommission on Cambrian Stratigraphy Annual Report 2017"(PDF).International Commission on Stratigraphy.Archived(PDF)from the original on 2023-07-16.Retrieved2024-03-27.
- ^"ISCS Working Groups: Working Group on the Stage 3 GSSP".International Subcommission on Cambrian Stratigraphy.Archivedfrom the original on 2023-09-26.
- ^"GSSP Table - Paleozoic Era".Geologic Timescale Foundation.Archivedfrom the original on 2023-10-08.Retrieved2024-03-27.
- ^"The 13th International Field Conference of the Cambrian Stage Subdivision Working Group"(PDF).Episodes.31(4): 440–441. Archived fromthe original(PDF)on 2014-11-05.Retrieved2024-03-27.
- ^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.Archived fromthe original(PDF)on 2024-01-18.Retrieved2024-03-27.
- ^Degan Shu, Yukio Isozaki, Xingliang Zhang, Jan Han, Shigenori Maruyama (2014)."Birth and early evolution of metazoans".Gondwana Research.25(3): 884—895.Bibcode:2014GondR..25..884S.doi:10.1016/j.gr.2013.09.001.
{{cite journal}}:CS1 maint: multiple names: authors list (link)
External links[edit]
- "GSSP Table - Paleozoic Era".Geologic Timescale Foundation.Archivedfrom the original on 2023-10-08.Retrieved2024-06-13.
- "GSSPs - The Cambrian System 2019".International Commission on Stratigraphy.Archivedfrom the original on 2023-07-21.
