| Cambrian Stage 4 | ||||||||||||||||||||||||||||||||||||||
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| 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 | FAD of the Trilobite Olenellus or Redlichia | |||||||||||||||||||||||||||||||||||||
| Lower boundary GSSP candidate section(s) | None | |||||||||||||||||||||||||||||||||||||
| Upper boundary definition | FAD of Oryctocephalus indicus. | |||||||||||||||||||||||||||||||||||||
| Upper boundary GSSP | Wuliu-Zengjiayan, Guizhou, China 26°04′51″N 108°24′50″E / 26.0807°N 108.4138°E | |||||||||||||||||||||||||||||||||||||
| Upper GSSP ratified | 2018[2] | |||||||||||||||||||||||||||||||||||||
Cambrian Stage 4 is the still unnamed fourth stage of the Cambrian and the upper stage of Cambrian Series 2. It follows Cambrian Stage 3 and lies below the Wuliuan. The lower boundary has not been formally defined by the International Commission on Stratigraphy. One proposal is the first appearance of two trilobite genera, Olenellus or Redlichia. Another proposal is the first appearance of the trilobite species Arthricocephalus chauveaui.[3] Both proposals will set the lower boundary close to 514 million years ago.[4] The upper boundary corresponds to the beginning of the Wuliuan.
Naming
The International Commission on Stratigraphy has not named the fourth stage of the Cambrian yet. In the widely used Siberian nomenclature stage 4 would overlap with parts of the Botomian and Toyonian.[5]
Biostratigraphy
The beginning of Cambrian Stage 4 has been tentatively correlated with the base of the European Leonian faunal stage and the base of the South China Duyunian faunal stage.[6]
References
- ↑ "Chart/Time Scale". stratigraphy.org. International Commission on Stratigraphy.
- ↑ Zhao; et al. (June 2019). "Global Standard Stratotype-Section and Point (GSSP) for the conterminous base of the Miaolingian Series and Wuliuan Stage (Cambrian) at Balang, Jianhe, Guizhou, China" (PDF). Episodes. 42 (2): 165–184. doi:10.18814/epiiugs/2019/019013. S2CID 202181406. Retrieved 8 December 2020.
- ↑ Peng, S.C.; Babcock, L.E. (21 September 2011). "Continuing progress on chronostratigraphic subdivision of the Cambrian System" (PDF). Bulletin of Geosciences: 391–396. doi:10.3140/bull.geosci.1273. Retrieved 21 November 2012.
- ↑ "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. Archived from the original (PDF) on 2014-11-05. Retrieved 2012-11-21.
- ↑ Yuan, Jinliang; Ng, Tin-Wai (2014). "Tentative correlation of the Duyunian (Cambrian Series 2, Stage 4) and the Taijiangian (Cambrian Series 3, Stage 5) between South China and the Mediterranean region". GFF. Geological Society of Sweden. 136 (1/2): 314–319. doi:10.1080/11035897.2014.898331. S2CID 129488362.
