Assessing the expansion of the Cambrian Agronomic Revolution into fan-delta environments
The intensity, extent, and ecosystem-level impact of bioturbation (i.e. Agronomic Revolution) at the dawn of the Phanerozoic is a hotly debated issue. Middle Cambrian fan-delta deposits in southwestern Saskatchewan provide insights into the paleoenvironmental extent of the Agronomic Revolution into...
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| Published in: | Scientific reports Vol. 12; no. 1; p. 14431 |
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| Main Authors: | , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
London
Nature Publishing Group UK
24-08-2022
Nature Publishing Group Nature Portfolio |
| Subjects: | |
| Online Access: | Get full text |
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| Summary: | The intensity, extent, and ecosystem-level impact of bioturbation (i.e. Agronomic Revolution) at the dawn of the Phanerozoic is a hotly debated issue. Middle Cambrian fan-delta deposits in southwestern Saskatchewan provide insights into the paleoenvironmental extent of the Agronomic Revolution into marginal-marine environments. The studied deposits reveal that several environmental stressors had direct impact on trace-fossil distribution and bioturbation intensities in Cambrian fan deltas. Basal and proximal subaerial deposits are characterized by very coarse grain size and absence of bioturbation. Mid-fan and fan-toe deposits were formed under subaqueous conditions and are characterized by rapid bioturbation events in between sedimentation episodes when environmental stressors were ameliorated, providing evidence of a significant landward expansion of the Agronomic Revolution. Transgressive marine deposits accumulated after the abandonment of the fan-delta system display high levels of bioturbation intensity, reflecting stable environmental conditions that favored endobenthic colonization. The presence of intense bioturbation in both subaqueous fan delta and transgressive deposits provides further support to the view that Cambrian levels of biogenic mixing were high, provided that stable environmental conditions were reached. Our study underscores the importance of evaluating sedimentary facies changes to assess the impact of environmental factors prior to making evolutionary inferences. |
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| Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 2045-2322 2045-2322 |
| DOI: | 10.1038/s41598-022-18199-4 |