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Shuram excursion

Topic: Earth

 From HandWiki - Reading time: 3 min

The Shuram excursion, or Shuram-Wonoka excursion, is a change in δ13C, or in the ratio of carbon-13 to carbon-12, taking place during the Ediacaran Period. The exact time period of the excursion is debated among scholars, beginning around 573 Ma and ending around 562[1] or 551[2] Ma. It was first noticed in the Wonoka Formation in South Australia in 1990 and later in the Clemente Formation of Mexico in 1992 [3] and the Shuram Formation in Oman in 1993.[4] It is the largest negative δ13C excursion in Earth history, and recovery took 50 million years,[5] although the apparent magnitude of the excursion may be distorted due to meteoric water diagenesis.[6]

It is not known what caused the excursion.[7] The Shuram excursion may have played a role in sparking the rise of animals that resulted later in the Cambrian explosion.[8] The oxygen-consuming Ediacara biota experienced a radiation during the isotopic excursion as a response to the transient surplus of oxidants.[9] Microbial blooms of oxygenic phototrophs regulated the recovery of the carbon cycle from the isotopic excursion.[10]

References

  1. ↑ Canfield, Donald Eugene; Knoll, Andrew H.; Poulton, Simon W.; Narbonne, Guy M.; Dunning, Gregory R. (February 2020). "Carbon isotopes in clastic rocks and the Neoproterozoic carbon cycle". American Journal of Science 320 (2): 97–124. doi:10.2475/02.2020.01. Bibcode: 2020AmJS..320...97C. https://www.ajsonline.org/content/320/2/97. Retrieved 12 March 2023. 
  2. ↑ Shi, Wei; Li, Chao; Luo, Genming; Huang, Junhua; Algeo, Thomas J.; Jin, Chengsheng; Zhang, Zihu; Cheng, Meng (24 January 2018). "Sulfur isotope evidence for transient marine-shelf oxidation during the Ediacaran Shuram Excursion". Geology 46 (3): 267–270. doi:10.1130/G39663.1. Bibcode: 2018Geo....46..267S. https://pubs.geoscienceworld.org/gsa/geology/article/46/3/267/526708/Sulfur-isotope-evidence-for-transient-marine-shelf. 
  3. ↑ McMenamin, M.A.S; Rowland, S.M.; Corsetti, F.; Dix, A.M.; Nance, R.P. (1992). "Vendian body fossils (?) and isotope stratigraphy from the Caborca area, Sonora, Mexico.". Fifth North American Paleontological Convention Abstracts and Program, Paleontological Society Special Publication 5: 206. doi:10.1017/S2475262200007668. 
  4. ↑ George Williams and Phillip Schmidt (March 2018). "Shuram–Wonoka carbon isotope excursion: Ediacaran revolution in the world ocean's meridional overturning circulation". Geoscience Frontiers 9 (2): 391–402. doi:10.1016/j.gsf.2017.11.006. Bibcode: 2018GeoFr...9..391W. 
  5. ↑ Erwan Le Guerroué (20 April 2006). "Chemostratigraphic and sedimentological framework of the largest negative carbon isotopic excursion in Earth history: The Neoproterozoic Shuram Formation (Nafun Group, Oman)". Precambrian Research 146 (1–2): 68–92. doi:10.1016/j.precamres.2006.01.007. Bibcode: 2006PreR..146...68L. https://www.sciencedirect.com/science/article/abs/pii/S0301926806000179. Retrieved 12 March 2023. 
  6. ↑ Cui, Huan (15 September 2022). "Ediacaran Shuram Excursion interpreted, reinterpreted, and misinterpreted: A comment" (in en). Precambrian Research 380. doi:10.1016/j.precamres.2022.106826. Bibcode: 2022PreR..38006826C. https://linkinghub.elsevier.com/retrieve/pii/S0301926822002704. Retrieved 18 December 2023. 
  7. ↑ Wei, Guang-Yi; Wang, Jiuyuan; Planavsky, Noah J.; Zhao, Mingyu; Bolton, Edward W.; Jiang, Lei; Asael, Dan; Wei, Wei et al. (1 July 2022). "On the origin of Shuram carbon isotope excursion in South China and its implication for Ediacaran atmospheric oxygen levels". Precambrian Research 375. doi:10.1016/j.precamres.2022.106673. Bibcode: 2022PreR..37506673W. 
  8. ↑ Colin Barras (Nov 9, 2019). "The weird creatures that might be the very first complex animals". New Scientist. https://www.newscientist.com/article/mg24432550-700-the-weird-creatures-that-might-be-the-very-first-complex-animals/. 
  9. ↑ Shields, Graham A.; Mills, Benjamin J. W.; Zhu, Maoyan; Raub, Timothy D.; Daines, Stuart J.; Lenton, Timothy M. (2 September 2019). "Unique Neoproterozoic carbon isotope excursions sustained by coupled evaporite dissolution and pyrite burial". Nature Geoscience 12 (10): 823–827. doi:10.1038/s41561-019-0434-3. Bibcode: 2019NatGe..12..823S. https://www.nature.com/articles/s41561-019-0434-3?error=cookies_not_supported&code=5b84f102-268e-4f63-8332-ea92a0ee76ea. Retrieved 12 January 2023. 
  10. ↑ Cañadas, Fuencisla; Papineau, Dominic; Leng, Melanie J.; Li, Chao (10 January 2022). "Extensive primary production promoted the recovery of the Ediacaran Shuram excursion". Nature Communications 13 (1): 148. doi:10.1038/s41467-021-27812-5. PMID 35013337. Bibcode: 2022NatCo..13..148C. 



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