No evidence for a volcanic trigger for late Cambrian carbon-cycle perturbations
The early Paleozoic was marked by several carbon-cycle perturbations and associated carbon-isotope excursions (CIEs). Whether these CIEs are connected to significant (external) triggers, as is commonly considered to be the case for CIEs in the Mesozoic and Cenozoic, or result from small carbon-cycle...
| Main Authors: | , , , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
Geological Society of America
2023
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| _version_ | 1826312915583500288 |
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| author | Frieling, J Mather, TA Fendley, IM Jenkyns, HC Zhao, Z Dahl, TW Bergquist, BA Cheng, K Nielsen, AT Dickson, AJ |
| author_facet | Frieling, J Mather, TA Fendley, IM Jenkyns, HC Zhao, Z Dahl, TW Bergquist, BA Cheng, K Nielsen, AT Dickson, AJ |
| author_sort | Frieling, J |
| collection | OXFORD |
| description | The early Paleozoic was marked by several carbon-cycle perturbations and associated carbon-isotope excursions (CIEs). Whether these CIEs are connected to significant (external) triggers, as is commonly considered to be the case for CIEs in the Mesozoic and Cenozoic, or result from small carbon-cycle imbalances that became amplified through lack of efficient silicate weathering or other feedbacks remains unclear. We present concentration and isotope data for sedimentary mercury (Hg) and osmium (Os) to assess the impact of subaerial and submarine volcanism and weathering during the late Cambrian and early Ordovician. Data from the Alum Shale Formation (Sweden) cover the Steptoean positive carbon-isotope excursion (SPICE; ca. 497–494 Ma), a period marked by marine anoxia and biotic overturning, and several smaller CIEs extending into the early Ordovician. Our Hg and Os data offer no strong evidence that the CIEs present in our record were driven by (globally) elevated volcanism or continental weathering. Organic-carbon and Hg concentrations covary cyclically, providing further evidence of an unperturbed Hg cycle. Mesozoic and Cenozoic CIEs are commonly linked to enhanced volcanic activity and weathering, but similar late Cambrian–early Ordovician events cannot easily be connected to such external triggers. Our results are more consistent with reduced early Paleozoic carbon-cycle resilience that allowed small imbalances to develop into large CIEs. |
| first_indexed | 2024-03-07T08:05:51Z |
| format | Journal article |
| id | oxford-uuid:ead677f3-7e75-47ee-bb94-1a6a7c05a847 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-09-25T04:02:43Z |
| publishDate | 2023 |
| publisher | Geological Society of America |
| record_format | dspace |
| spelling | oxford-uuid:ead677f3-7e75-47ee-bb94-1a6a7c05a8472024-04-25T07:37:43ZNo evidence for a volcanic trigger for late Cambrian carbon-cycle perturbationsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:ead677f3-7e75-47ee-bb94-1a6a7c05a847EnglishSymplectic ElementsGeological Society of America2023Frieling, JMather, TAFendley, IMJenkyns, HCZhao, ZDahl, TWBergquist, BACheng, KNielsen, ATDickson, AJThe early Paleozoic was marked by several carbon-cycle perturbations and associated carbon-isotope excursions (CIEs). Whether these CIEs are connected to significant (external) triggers, as is commonly considered to be the case for CIEs in the Mesozoic and Cenozoic, or result from small carbon-cycle imbalances that became amplified through lack of efficient silicate weathering or other feedbacks remains unclear. We present concentration and isotope data for sedimentary mercury (Hg) and osmium (Os) to assess the impact of subaerial and submarine volcanism and weathering during the late Cambrian and early Ordovician. Data from the Alum Shale Formation (Sweden) cover the Steptoean positive carbon-isotope excursion (SPICE; ca. 497–494 Ma), a period marked by marine anoxia and biotic overturning, and several smaller CIEs extending into the early Ordovician. Our Hg and Os data offer no strong evidence that the CIEs present in our record were driven by (globally) elevated volcanism or continental weathering. Organic-carbon and Hg concentrations covary cyclically, providing further evidence of an unperturbed Hg cycle. Mesozoic and Cenozoic CIEs are commonly linked to enhanced volcanic activity and weathering, but similar late Cambrian–early Ordovician events cannot easily be connected to such external triggers. Our results are more consistent with reduced early Paleozoic carbon-cycle resilience that allowed small imbalances to develop into large CIEs. |
| spellingShingle | Frieling, J Mather, TA Fendley, IM Jenkyns, HC Zhao, Z Dahl, TW Bergquist, BA Cheng, K Nielsen, AT Dickson, AJ No evidence for a volcanic trigger for late Cambrian carbon-cycle perturbations |
| title | No evidence for a volcanic trigger for late Cambrian carbon-cycle perturbations |
| title_full | No evidence for a volcanic trigger for late Cambrian carbon-cycle perturbations |
| title_fullStr | No evidence for a volcanic trigger for late Cambrian carbon-cycle perturbations |
| title_full_unstemmed | No evidence for a volcanic trigger for late Cambrian carbon-cycle perturbations |
| title_short | No evidence for a volcanic trigger for late Cambrian carbon-cycle perturbations |
| title_sort | no evidence for a volcanic trigger for late cambrian carbon cycle perturbations |
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