Earth:Wuliuan
| Wuliuan | |
|---|---|
| ~509 – ~504.5 Ma | |
| Chronology | |
Cambrian graphical timeline -540 — – -535 — – -530 — – -525 — – -520 — – -515 — – -510 — – -505 — – -500 — – -495 — – -490 — – -485 — – Major Glacial period | |
| Etymology | |
| Name formality | Formal |
| Former name(s) | Cambrian Stage 5 |
| Usage information | |
| Celestial body | Earth |
| Regional usage | Global (ICS) |
| Time scale(s) used | ICS Time Scale |
| Definition | |
| Chronological unit | Age |
| Stratigraphic unit | Stage |
| First proposed by | Zhao et al., 2018[2] |
| Time span formality | Formal |
| Lower boundary definition | FAD of Oryctocephalus indicus. |
| Lower boundary GSSP | Wuliu-Zengjiayan, Guizhou, China [ ⚑ ] 26°04′51″N 108°24′50″E / 26.0807°N 108.4138°E |
| GSSP ratified | 2018[3] |
| Upper boundary definition | FAD of the Trilobite Ptychagnostus atavus |
| Upper boundary GSSP | Drumian section, Wheeler Shale, Utah, United States [ ⚑ ] 39°30′42″N 112°59′29″W / 39.5117°N 112.9915°W |
| GSSP ratified | 2006[4] |
The Wuliuan stage is the fifth stage of the Cambrian, and the first stage of the Miaolingian Series of the Cambrian. It was formally defined by the International Commission on Stratigraphy in 2018.[5] Its base is defined by the first appearance of the trilobite species Oryctocephalus indicus; it ends with the beginning of the Drumian Stage, marked by the first appearance of the trilobite Ptychagnostus atavus around 504.5 million years ago.[6]
The 'golden spike' that formally defines the base of the period is driven into the Wuliu-Zengjiayan(乌溜-曾家崖)section of the Kaili formation, near Balang Village in the Miaoling Mountains, Guizhou, China.[7]
GSSP
Three sections were discussed as GSSP candidates: the Wuliu-Zengjiayan section near Balang in Guizhou province (China), a section on Split Mountain in Nevada (USA)[6] and the "Molodo river section" along the Molodo river (Sakha Republic, Russia).[8] The Wuliu-Zengjiayan section is an outcrop of the Kaili Formation in the Wuliu quarry. The first candidate for the beginning of the Wuliuan was the trilobite Oryctocephalus indicus, the second candidate was the trilobite Ovatoryctocara granulata.[9]
The Wuliu-Zengjiayan section was chosen as the formal base in 2018, with the first appearance of Oryctocephalus indicus being chosen as the defining marker for the GSSP.[3]
References
- ↑ "Chart/Time Scale". International Commission on Stratigraphy. http://www.stratigraphy.org/index.php/ics-chart-timescale.
- ↑ Yuanlong, Zhao; Jinliang, Yuan; Babcock, Loren; Qingjun, Guo; Jin, Peng; Leiming, Yin; Xinglian, Yang; Chunjiang, Wang et al.. "PROPOSED GLOBAL STANDARD STRATOTYPE-SECTION AND POINT FOR THE BASE OF THE MIAOLINGIAN SERIES AND WULIUAN STAGE （REPLACING PROVISIONAL CAMBRIAN SERIES 3 AND STAGE 5）". International Subcommission on Cambrian Stratigraphy. http://www.palaeontology.geo.uu.se/ISCS/ISCS_GSSPs.html.
- ↑ 3.0 3.1 Cite error: Invalid
<ref>tag; no text was provided for refs namedZhao2019 - ↑ Babcock, Loren; Robison, Richard; Rees, Margaret; Peng, Shanchi; Saltzman, Matthew (June 2007). "The Global boundary Stratotype Section and Point (GSSP) of the Drumian Stage (Cambrian) in the Drum Mountains, Utah, USA". Episodes 30 (2): 85–89. doi:10.18814/epiiugs/2007/v30i2/003. https://www.researchgate.net/publication/279605638. Retrieved 13 December 2020.
- ↑ "ChronostratChart2018-08". http://www.stratigraphy.org/icschart/ChronostratChart2018-08.pdf.
- ↑ 6.0 6.1 "GSSP Table - Paleozoic Era". https://engineering.purdue.edu/Stratigraphy/gssp/index.php?parentid=77.
- ↑ "ISCS Annual Report 2017.pdf". http://www.palaeontology.geo.uu.se/ISCS/ISCS%20Annual%20Report%202017.pdf.
- ↑ "The 13th International Field Conference of the Cambrian Stage Subdivision Working Group". Episodes 31 (4): 440–441. http://www.episodes.co.in/www/backissues/314/440-442%20Confreport-Russia,%202%20(3).pdf.
- ↑ Sundberg, F.A.; Zhao, Y.L.; Yuan, J.L.; Lin, J.P. (22 September 2011). "Detailed trilobite biostratigraphy across the proposed GSSP for Stage 5 ("Middle Cambrian" boundary) at the Wuliu-Zengjiayan section, Guizhou, China". Bulletin of Geosciences: 423–464. doi:10.3140/bull.geosci.1211.
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