Cambrian Series 2
| Cambrian Series 2 | |||||||
|---|---|---|---|---|---|---|---|
| Chronology | |||||||
| |||||||
| |||||||
Subdivision of the Cambrian according to the Epoch | |||||||
| Stratigraphic unit | Series | ||||||
| Time span formality | Formal | ||||||
| Lower boundary definition | Not formally defined | ||||||
| Lower boundary definition candidates | FAD of Trilobites | ||||||
| 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 Series 2 is the unnamed 2nd series of the
Naming
The International Commission on Stratigraphy has not named the 2nd series of the Cambrian yet.[3] In part the new name will replace the older terms "Lower Cambrian" and "Early Cambrian". The nomenclature used in Siberia uses the term "Yakutian" for this series.[5]
Subdivisions
The 2nd series is currently subdivided by the
Toyonian.[5] In general most subdivisions of this series rely on biostratigraphy of trilobite zones.[6]
Biostratigraphy
The beginning of the 2nd series of the Cambrian is marked by the appearance of
trilobites. Correlating this event on different continents has proven difficult and resolving this is essential for the definition of the lower boundary of this series. Currently the oldest trilobite known is Lemdadella which marks the beginning of the Fallotaspis zone.[6]
The end of the 2nd series of the Cambrian is marked by the first major biotic extinction of the
ocean chemistry and the marine environment are posited as the most likely cause of these extinctions.[7]
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: 165–184. Retrieved 8 December 2020.
- ^ a b c "GSSP Table - Paleozoic Era". Retrieved 18 November 2012.
- ISSN 2391-5447.
- ^ a b "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 2012-11-23.
- ^ . Retrieved 23 November 2012.
- .
