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Geochemical evidence for widespread euxinia in the later Cambrian ocean.
Nature. 2011 Jan 06; 469(7328):80-3.Nat

Abstract

Widespread anoxia in the ocean is frequently invoked as a primary driver of mass extinction as well as a long-term inhibitor of evolutionary radiation on early Earth. In recent biogeochemical studies it has been hypothesized that oxygen deficiency was widespread in subsurface water masses of later Cambrian oceans, possibly influencing evolutionary events during this time. Physical evidence of widespread anoxia in Cambrian oceans has remained elusive and thus its potential relationship to the palaeontological record remains largely unexplored. Here we present sulphur isotope records from six globally distributed stratigraphic sections of later Cambrian marine rocks (about 499 million years old). We find a positive sulphur isotope excursion in phase with the Steptoean Positive Carbon Isotope Excursion (SPICE), a large and rapid excursion in the marine carbon isotope record, which is thought to be indicative of a global carbon cycle perturbation. Numerical box modelling of the paired carbon sulphur isotope data indicates that these isotope shifts reflect transient increases in the burial of organic carbon and pyrite sulphur in sediments deposited under large-scale anoxic and sulphidic (euxinic) conditions. Independently, molybdenum abundances in a coeval black shale point convincingly to the transient spread of anoxia. These results identify the SPICE interval as the best characterized ocean anoxic event in the pre-Mesozoic ocean and an extreme example of oxygen deficiency in the later Cambrian ocean. Thus, a redox structure similar to those in Proterozoic oceans may have persisted or returned in the oceans of the early Phanerozoic eon. Indeed, the environmental challenges presented by widespread anoxia may have been a prevalent if not dominant influence on animal evolution in Cambrian oceans.

Authors+Show Affiliations

Department of Earth Sciences, University of California, 900 University Avenue, Riverside, California 92521, USA. bgill@fas.harvard.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Historical Article
Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

21209662

Citation

Gill, Benjamin C., et al. "Geochemical Evidence for Widespread Euxinia in the Later Cambrian Ocean." Nature, vol. 469, no. 7328, 2011, pp. 80-3.
Gill BC, Lyons TW, Young SA, et al. Geochemical evidence for widespread euxinia in the later Cambrian ocean. Nature. 2011;469(7328):80-3.
Gill, B. C., Lyons, T. W., Young, S. A., Kump, L. R., Knoll, A. H., & Saltzman, M. R. (2011). Geochemical evidence for widespread euxinia in the later Cambrian ocean. Nature, 469(7328), 80-3. https://doi.org/10.1038/nature09700
Gill BC, et al. Geochemical Evidence for Widespread Euxinia in the Later Cambrian Ocean. Nature. 2011 Jan 6;469(7328):80-3. PubMed PMID: 21209662.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Geochemical evidence for widespread euxinia in the later Cambrian ocean. AU - Gill,Benjamin C, AU - Lyons,Timothy W, AU - Young,Seth A, AU - Kump,Lee R, AU - Knoll,Andrew H, AU - Saltzman,Matthew R, PY - 2010/06/21/received PY - 2010/11/16/accepted PY - 2011/1/7/entrez PY - 2011/1/7/pubmed PY - 2011/2/10/medline SP - 80 EP - 3 JF - Nature JO - Nature VL - 469 IS - 7328 N2 - Widespread anoxia in the ocean is frequently invoked as a primary driver of mass extinction as well as a long-term inhibitor of evolutionary radiation on early Earth. In recent biogeochemical studies it has been hypothesized that oxygen deficiency was widespread in subsurface water masses of later Cambrian oceans, possibly influencing evolutionary events during this time. Physical evidence of widespread anoxia in Cambrian oceans has remained elusive and thus its potential relationship to the palaeontological record remains largely unexplored. Here we present sulphur isotope records from six globally distributed stratigraphic sections of later Cambrian marine rocks (about 499 million years old). We find a positive sulphur isotope excursion in phase with the Steptoean Positive Carbon Isotope Excursion (SPICE), a large and rapid excursion in the marine carbon isotope record, which is thought to be indicative of a global carbon cycle perturbation. Numerical box modelling of the paired carbon sulphur isotope data indicates that these isotope shifts reflect transient increases in the burial of organic carbon and pyrite sulphur in sediments deposited under large-scale anoxic and sulphidic (euxinic) conditions. Independently, molybdenum abundances in a coeval black shale point convincingly to the transient spread of anoxia. These results identify the SPICE interval as the best characterized ocean anoxic event in the pre-Mesozoic ocean and an extreme example of oxygen deficiency in the later Cambrian ocean. Thus, a redox structure similar to those in Proterozoic oceans may have persisted or returned in the oceans of the early Phanerozoic eon. Indeed, the environmental challenges presented by widespread anoxia may have been a prevalent if not dominant influence on animal evolution in Cambrian oceans. SN - 1476-4687 UR - https://www.unboundmedicine.com/medline/citation/21209662/Geochemical_evidence_for_widespread_euxinia_in_the_later_Cambrian_ocean_ L2 - https://doi.org/10.1038/nature09700 DB - PRIME DP - Unbound Medicine ER -