Cambrian Stage 2
| Cambrian Stage 2 | ||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chronology | ||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||
| 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 | First appearance ofsmall shelly faunaorArchaeocyathids | |||||||||||||||||||||||||||||||||||||
| Lower boundary GSSP candidate section(s) | None | |||||||||||||||||||||||||||||||||||||
| Upper boundary definition | Not formally defined | |||||||||||||||||||||||||||||||||||||
| Upper boundary definition candidates | FADofTrilobites | |||||||||||||||||||||||||||||||||||||
| Upper boundary GSSP candidate section(s) | None | |||||||||||||||||||||||||||||||||||||
Stage 2of theCambrianis the unnamed upperstageof theTerreneuvianSeries. It lies atop theFortunianand belowStage 3of the Cambrian. It is commonly referred to as theTommotian,after the Cambrian stratigraphy of Siberia.[2][3]Neither the upper nor lower boundary has yet been defined by theInternational Commission on Stratigraphy.[4][5] The preferred definitions for the lower boundary are thefirst appearanceof themolluscsWatsonella crosbyiorAldanella attleborensisaround 529 million years ago.[6][7]The correlation between the lowest occurrences ofA. attleborensisandW. crosbyiwith the Zhujiaqing positive carbon isotope excursion (ZHUCE) has led to the conclusion that the combination of these two markers are a reliable indicator of the boundary between the Fortunian and Stage 2.[8]The proposed upper boundary might be the first appearance oftrilobitesaround 521 million years ago.[4]
Naming
[edit]The name"Laolinian"after the Laolin village inYunnan,China, was proposed for the Stage 2 in 2012.[9]
Stratotype
[edit]Possible candidates for aGSSPinclude the first appearance ofWatsonella crosbyiin the Zhujiaqing Formation ( Chu gia khánh tổ ) in Yunnan, China or the Pestrotsvet Formation near theAldan Riveron theSiberian Platform.[10]
References
[edit]- ^"Chart/Time Scale".stratigraphy.org.International Commission on Stratigraphy.
- ^Kouchinsky, Artem; Bengtson, Stefan; Missarzhevsky, Vladimir V.; Pelechaty, Shane; Torssander, Peter; Val'kov, Anatolij K. (24 September 2001). "Carbon isotope stratigraphy and the problem of a pre-Tommotian stage in Siberia".Geological Magazine.138(4): 387–396.Bibcode:2001GeoM..138..387K.doi:10.1017/S0016756801005684.S2CID3884375.
- ^Landing, E.; Kouchinsky, A. V. (2016)."Correlation of the Cambrian Evolutionary Radiation: geochronology, evolutionary stasis of earliest Cambrian (Terreneuvian) small shelly fossil (SSF) taxa, and chronostratigraphic significance".Geol. Mag.153(4): 750–756.Bibcode:2016GeoM..153..750L.doi:10.1017/s0016756815001089.S2CID132867265.
- ^ab"GSSP List ICS".ICS. Archived fromthe originalon 15 November 2012.Retrieved2024-03-26.
- ^P. Yu. Parkhaev, Yu. E. Demidenko, M. A. Kulsha (2020)."ZooproblematicaMobergella radiolataas Index Species of the Lower Cambrian Stage Units "(PDF).Стратиграфия. Геологическая корреляция(in Russian).28(2): 34.doi:10.31857/S0869592X20020064.Archived(PDF)from the original on 2024-01-30.
{{cite journal}}:CS1 maint: multiple names: authors list (link) - ^"ISCS Working Groups: Working Group on the Stage 2 GSSP".International Subcommission on Cambrian Stratigraphy.Archivedfrom the original on 2023-09-26.
- ^Yaqin Qiang, Junfeng Guo, Guoxiang Li, Zuchen Song, Jiaxin Peng, Jie Sun, Jian Han, Zhifei Zhang (2023)."Aldanella attleborensis(Mollusca) from Cambrian Stage 2 of the Three Gorges Area and Its Stratigraphic Implications ".Biology.12(2): 1—21.doi:10.3390/biology12020261.PMC9953005.PMID36829538.
{{cite journal}}:CS1 maint: multiple names: authors list (link) - ^Yang, Chuan; Bowyer, Fred T.; Condon, Daniel J.; Li, Xian-Hua; Zhu, Maoyan (15 April 2023)."New U-Pb age from the Shuijingtuo Formation (Yangtze Gorges area) and its implications for the Cambrian timescale".Palaeogeography, Palaeoclimatology, Palaeoecology.616:111477.Bibcode:2023PPP...61611477Y.doi:10.1016/j.palaeo.2023.111477.ISSN0031-0182.Retrieved2024-03-26– via Elsevier Science Direct.
- ^Ed Landing, Gerd Geyer, Adam C. Maloof, Martin B. Brasier, Samuel A. Bowring (2013)."Proposal of the global stratotype section and point for the Laolinian Stage (=informal Cambrian Stage 2) as the upper stage of the Terreneuvian Series".International Cambrian Subcommission:1—43.doi:10.13140/RG.2.1.4198.1842.
{{cite journal}}:CS1 maint: multiple names: authors list (link) - ^Li, Guoxiang; Zhao, Xin; Gubanov, Alexander; Zhu, Maoyan; Na, Lin (1 April 2011). "Early Cambrian Mollusc Watsonella crosbyi: A Potential GSSP Index Fossil for the Base of the Cambrian Stage 2".Acta Geologica Sinica - English Edition.85(2): 309–319.Bibcode:2011AcGlS..85..309L.doi:10.1111/j.1755-6724.2011.00400.x.S2CID129506892.
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.
 | Thisgeochronologyarticle is astub.You can help Wikipedia byexpanding it. |
 | This article related to theCambrianperiodis astub.You can help Wikipedia byexpanding it. |