Cambrian Series 2

Short description: Unnamed 2nd series of the Cambrian

Cambrian Series 2

~521 – ~509 Ma

PreЄ

A map of Earth 515 million years ago during the Cambrian's 2nd series, Stage 3

Chronology

Cambrian graphical timeline

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-540 --

-535 --

-530 --

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-520 --

-515 --

-510 --

-505 --

-500 --

-495 --

-490 --

-485 --

Ediacaran

Early O

Fortunian

"Stage 2"

"Stage 3"

"Stage 4"

Wuliuan

Drumian

Guzhangian

Paibian

Jiangshanian

"Stage 10"

Orsten Fauna

Burgess Shale

Kaili biota

Archaeocyatha extinction

Emu Bay Shale

Sirius Passet biota

Chengjiang biota

First Trilobites

SSF diversification, first brachiopods & archaeocyatha

First halkieriids, mollusсs, hyoliths SSF

Baykonurian glaciation

Dresbachian extinction

Major Glacial period

Subdivision of the Cambrian according to the ICS, as of 2021.[1]
Vertical axis scale: millions of years ago

Etymology
Name formality| Informal
Usage information
Celestial body| Earth
Regional usage| Global (ICS)
Time scale(s) used| ICS Time Scale
Definition
Chronological unit| 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
GSSP ratified| Template:Period start ratification
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 / 26.0807; 108.4138
GSSP ratified| Template:Period end ratification

Cambrian Series 2 or Mid-Early Cambrian is the unnamed 2nd series of the Cambrian. It lies above the Terreneuvian series and below the Miaolingian. Series 2 has not been formally defined by the International Commission on Stratigraphy, lacking a precise lower boundary and subdivision into stages. The proposed lower boundary is the first appearance of trilobites which is estimated to be around 521 million years ago.[2][3]

## Contents

* 1 Naming
* 2 Subdivisions
* 3 Biostratigraphy
* 4 References
* 5 External links

## Naming

The International Commission on Stratigraphy has not named the 2nd series of the Cambrian yet.[2] 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.[4]

## Subdivisions

The 2nd series is currently subdivided by the ICS into two stages: Cambrian Stage 3 and Cambrian Stage 4. Both of these stages also lack formal definition.[2] The Siberian nomenclature distinguishes three stages (lowest first): Atdabanian, Botomian and Toyonian.[4] In general most subdivisions of this series rely on biostratigraphy of trilobite zones.[5]

The Ordian stage, which is use in Australian chronostratigraphical scale, was originally supposed to be the lowest stage of the Miaolingian, but may belong to upper Series 2. As of 2024, the base of the Ordian is not defined yet.[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.[5]

The end of the 2nd series of the Cambrian is marked by the first major biotic extinction of the Paleozoic. Changes in ocean chemistry and the marine environment are posited as the most likely cause of this extinction.[7] At the Series 2–Miaolingian boundary, the first major trilobite extinction, known as the Olenellid Biomere boundary, occurred. In particular, trilobites of the families Olenellidae and Redlichiidae have been extinct in Laurentia and South China, respectively.[8] The first O. indicus appear after this global extinction, and in areas where O. indicus fossils are absent, the Series 2–Miaolingian boundary is determined by chemostratigraphic data.[9]

## References

1. ↑ "Chart/Time Scale". International Commission on Stratigraphy. http://www.stratigraphy.org/index.php/ics-chart-timescale.
2. ↑ 2.0 2.1 2.2 "GSSP Table - Paleozoic Era". https://engineering.purdue.edu/Stratigraphy/gssp/index.php?parentid=77.
3. ↑ Wu, Tong; Yang, Ruidong; Gao, Junbo; Li, Jun (1 January 2021). "Age of the lower Cambrian Vanadium deposit, East Guizhou, South China: Evidences from age of tuff and carbon isotope analysis along the Bagong section" (in en). Open Geosciences 13 (1): 999–1012. doi:10.1515/geo-2020-0287. ISSN 2391-5447. https://doi.org/10.1515/geo-2020-0287.
4. ↑ 4.0 4.1 "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 Confreport-Russia, 2 (3).pdf. Retrieved 2024-04-02.
5. ↑ 5.0 5.1 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". Bulletin of Geosciences: 397–404. doi:10.3140/bull.geosci.1274. http://www.geology.cz/bulletin/fulltext/1274_Yuan.pdf. Retrieved 2024-04-02.
6. ↑ John R. Laurie, Peter D. Kruse, Glenn A. Brock, James D. Holmes, James B. Jago, Marissa J. Betts, John R. Paterson, Patrick M. Smith (April 2024). "The quest for an Australian Cambrian stage scale". Alcheringa: An Australasian Journal of Palaeontology. doi:10.1080/03115518.2024.2327045. https://www.researchgate.net/publication/379507870.
7. ↑ Zhang, Wenhao (2014). "Mass-occurrence of oncoids at the Cambrian Series 2–Series 3 transition: Implications for microbial resurgence following an Early Cambrian extinction". Gondwana Research 28: 432–450. doi:10.1016/j.gr.2014.03.015.
8. ↑ Jih-Pai Lin, Frederick A. Sundberg, Ganqing Jiang, Isabel P. Montañez, Thomas Wotte (22 November 2019). "Chemostratigraphic correlations across the first major trilobite extinction and faunal turnovers between Laurentia and South China". Scientific Reports 9 (1): 17392. doi:10.1038/s41598-019-53685-2. PMC 6874646. https://www.nature.com/articles/s41598-019-53685-2.
9. ↑ Courtney Birksmith, Glenn A. Brock, Marissa J. Betts, James D. Holmes, Zhiliang Zhang (2023). "Chronostratigraphy of the Cambrian Series 2 -Miaolingian boundary, western Stansbury Basin, South Australia". Conference: Palaeo Down Under 3 at Perth, Western Australia. https://www.researchgate.net/publication/372885761.

## External links

* "GSSP Table - Paleozoic Era". https://timescalefoundation.org/gssp/index.php?parentid=77.
* "GSSPs - The Cambrian System 2019". International Commission on Stratigraphy. http://www.palaeontology.geo.uu.se/ISCS/ISCS_GSSPs.html.

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Geological history of Earth

Cenozoic era
(present–66.0 Mya)|

| Quaternary (present–2.588 Mya)|

* Holocene (present–11.784 kya)
* Pleistocene (11.784 kya–2.588 Mya)

|

Neogene (2.588–23.03 Mya)|

* Pliocene (2.588–5.333 Mya)
* Miocene (5.333–23.03 Mya)

Paleogene (23.03–66.0 Mya)|

* Oligocene (23.03–33.9 Mya)
* Eocene (33.9–56.0 Mya)
* Paleocene (56.0–66.0 Mya)

Mesozoic era
(66.0–251.902 Mya)|

| Cretaceous (66.0–145.0 Mya)|

* Late (66.0–100.5 Mya)
* Early (100.5–145.0 Mya)

|

Jurassic (145.0–201.3 Mya)|

* Late (145.0–163.5 Mya)
* Middle (163.5–174.1 Mya)
* Early (174.1–201.3 Mya)

Triassic (201.3–251.902 Mya)|

* Late (201.3–237 Mya)
* Middle (237–247.2 Mya)
* Early (247.2–251.902 Mya)

Paleozoic era
(251.902–541.0 Mya)|

| Permian (251.902–298.9 Mya)|

* Lopingian (251.902–259.8 Mya)
* Guadalupian (259.8–272.3 Mya)
* Cisuralian (272.3–298.9 Mya)

|

Carboniferous (298.9–358.9 Mya)|

* Pennsylvanian (298.9–323.2 Mya)
* Mississippian (323.2–358.9 Mya)

Devonian (358.9–419.2 Mya)|

* Late (358.9–382.7 Mya)
* Middle (382.7–393.3 Mya)
* Early (393.3–419.2 Mya)

Silurian (419.2–443.8 Mya)|

* Pridoli (419.2–423.0 Mya)
* Ludlow (423.0–427.4 Mya)
* Wenlock (427.4–433.4 Mya)
* Llandovery (433.4–443.8 Mya)

Ordovician (443.8–485.4 Mya)|

* Late (443.8–458.4 Mya)
* Middle (458.4–470.0 Mya)
* Early (470.0–485.4 Mya)

Cambrian (485.4–541.0 Mya)|

* Furongian (485.4–497 Mya)
* Miaolingian (497–509 Mya)
* Series 2 (509–521 Mya)
* Terreneuvian (521–541.0 Mya)

Proterozoic eon
(541.0 Mya–2.5 Gya)|

| Neoproterozoic (541.0 Mya–1 Gya)|

* Ediacaran (541.0–~635 Mya)
* Cryogenian (~635–~720 Mya)
* Tonian (~720 Mya–1 Gya)

|

Mesoproterozoic (1–1.6 Gya)|

* Stenian (1–1.2 Gya)
* Ectasian (1.2–1.4 Gya)
* Calymmian (1.4–1.6 Gya)

Paleoproterozoic (1.6–2.5 Gya)|

* Statherian (1.6–1.8 Gya)
* Orosirian (1.8–2.05 Gya)
* Rhyacian (2.05–2.3 Gya)
* Siderian (2.3–2.5 Gya)

Archean eon (2.5–4 Gya)|

| Eras|

* Neoarchean (2.5–2.8 Gya)
* Mesoarchean (2.8–3.2 Gya)
* Paleoarchean (3.2–3.6 Gya)
* Eoarchean (3.6–4 Gya)

|

Hadean eon (4–4.6 Gya)|

|  |

|

kya = thousands years ago. Mya = millions years ago. Gya = billions years ago.
See also: Geologic time scale

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