Steptoean positive carbon isotope excursion

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The Steptoean Positive Carbon Isotope Excursion (SPICE) was a geological event which occurred about 500 million years ago at the end of the Cambrian Period. The SPICE event was a positive shift in carbon isotope (Δ13C) values which lasted for around 2 to 4 million years.[1] This shift is interpreted to be a global disturbance in the carbon cycle, affecting both the ocean and atmosphere. Regional sea level changes and trilobite extinctions are associated with the SPICE event, although the exact mechanism(s) driving these events is still unconfirmed.[2][3]

One proposed cause of the SPICE is an increase in the burial of organic carbon, perhaps caused by increased primary productivity or enhanced organic matter preservation due to ocean stratification (i.e. anoxia or euxinia).[4][5] Seafloor anoxia has also been proposed as the kill mechanism for the trilobite extinctions.

References[]

  1. ^ Saltzman, M. R.; Cowan, C. A.; Runkel, A. C.; Runnegar, B.; Stewart, M. C.; Palmer, A. R. (2004-05-01). "The Late Cambrian Spice (13C) Event and the Sauk II-SAUK III Regression: New Evidence from Laurentian Basins in Utah, Iowa, and Newfoundland". Journal of Sedimentary Research. 74 (3): 366–377. doi:10.1306/120203740366. ISSN 1527-1404.
  2. ^ Gerhardt, Angela M.; Gill, Benjamin C. (2016-11-01). "Elucidating the relationship between the later Cambrian end-Marjuman extinctions and SPICE Event". Palaeogeography, Palaeoclimatology, Palaeoecology. 461: 362–373. doi:10.1016/j.palaeo.2016.08.031. ISSN 0031-0182.
  3. ^ Saltzman, Matthew R.; Ripperdan, Robert L.; Brasier, M. D.; Lohmann, Kyger C.; Robison, Richard A.; Chang, W. T.; Peng, Shanchi; Ergaliev, E. K.; Runnegar, Bruce (2000-10-01). "A global carbon isotope excursion (SPICE) during the Late Cambrian: relation to trilobite extinctions, organic-matter burial and sea level". Palaeogeography, Palaeoclimatology, Palaeoecology. 162 (3): 211–223. doi:10.1016/S0031-0182(00)00128-0. ISSN 0031-0182.
  4. ^ Wotte, Thomas; Strauss, Harald (2015). "Questioning a widespread euxinia for the Furongian (Late Cambrian) SPICE event: indications from δ13C, δ18O, δ34S and biostratigraphic constraints". Geological Magazine. 152 (6): 1085–1103. doi:10.1017/S0016756815000187. ISSN 0016-7568.
  5. ^ LeRoy, Matthew A.; Gill, Benjamin C.; Sperling, Erik A.; McKenzie, N. Ryan; Park, Tae-Yoon S. (2021-03-15). "Variable redox conditions as an evolutionary driver? A multi-basin comparison of redox in the middle and later Cambrian oceans (Drumian-Paibian)". Palaeogeography, Palaeoclimatology, Palaeoecology. 566: 110209. doi:10.1016/j.palaeo.2020.110209. ISSN 0031-0182.
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