Different accretion and diagenetic patterns within the fabrics of the Permian–Triassic boundary microbialites on the Leye isolated carbonate platform, South China Block
Abstract A comprehensive study on the accretion and diagenesis of the Permian–Triassic boundary microbialites is conducive to a better understanding of the ecological community after the end-Permian mass extinction. Here we studied the special microbialite sequences at the Tianba section of Leye iso...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2021-05-01
|
| Series: | Journal of Palaeogeography |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s42501-021-00091-3 |
| _version_ | 1818333164376948736 |
|---|---|
| author | Xi-Yang Zhang Yue Li Guan Wang Hong-Qiang Yang |
| author_facet | Xi-Yang Zhang Yue Li Guan Wang Hong-Qiang Yang |
| author_sort | Xi-Yang Zhang |
| collection | DOAJ |
| description | Abstract A comprehensive study on the accretion and diagenesis of the Permian–Triassic boundary microbialites is conducive to a better understanding of the ecological community after the end-Permian mass extinction. Here we studied the special microbialite sequences at the Tianba section of Leye isolated carbonate platform, South China Block. The microbialites are shown as small columnar stromatolites, stromatolitic thrombolites, spotted thrombolites, and domical digitate thrombolites in an ascending order. Thin section analyses, coupled with cathodoluminescence photos and oxygen isotopic data, reveal that all types of microbially-mediated laminae/clots are partly recrystallized. Layers of the Polybessurus-like fossils commonly occur in the recrystallized fabrics of stromatolitic laminae. However, the Polybessurus-like fossils are rare in quantity and generally fragmentary and structureless in stromatolitic clots and spotted clots. Such taphonomic features are likely interpreted as the early decomposition by heterotrophic bacteria in an oxygen-depleted microenvironment caused by rapid accumulations of organic matter in the calm water. More enrichments of 13C in the laminae of stromatolite and in the clots of stromatolitic thrombolite and spotted thrombolite than in adjacent interstitial matrixes signify the photosynthesis-dominated isotopic fractionation during the growth of microbial communities. Rare calcimicrobial structures but many calcite crystal fans were found in the 13C-depleted digitate clots. These phenomena indicate that seawater on the carbonate platform was 12C-enriched and supersaturated, accelerating carbonate precipitations and decompositions of organic matter within the microbial community. Different preservations of the Polybessurus-like fossil revealed the complicated microbially-dominated sedimentation and post-depositional diagenesis in the abnormal seawater after the catastrophe. |
| first_indexed | 2024-12-13T13:47:17Z |
| format | Article |
| id | doaj.art-bff06cfeb08a43e0ba0ba14a7482ea58 |
| institution | Directory Open Access Journal |
| issn | 2524-4507 |
| language | English |
| last_indexed | 2024-12-13T13:47:17Z |
| publishDate | 2021-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Palaeogeography |
| spelling | doaj.art-bff06cfeb08a43e0ba0ba14a7482ea582022-12-21T23:43:21ZengElsevierJournal of Palaeogeography2524-45072021-05-0110111210.1186/s42501-021-00091-3Different accretion and diagenetic patterns within the fabrics of the Permian–Triassic boundary microbialites on the Leye isolated carbonate platform, South China BlockXi-Yang Zhang0Yue Li1Guan Wang2Hong-Qiang Yang3Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of SciencesState Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of SciencesKey Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of SciencesKey Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of SciencesAbstract A comprehensive study on the accretion and diagenesis of the Permian–Triassic boundary microbialites is conducive to a better understanding of the ecological community after the end-Permian mass extinction. Here we studied the special microbialite sequences at the Tianba section of Leye isolated carbonate platform, South China Block. The microbialites are shown as small columnar stromatolites, stromatolitic thrombolites, spotted thrombolites, and domical digitate thrombolites in an ascending order. Thin section analyses, coupled with cathodoluminescence photos and oxygen isotopic data, reveal that all types of microbially-mediated laminae/clots are partly recrystallized. Layers of the Polybessurus-like fossils commonly occur in the recrystallized fabrics of stromatolitic laminae. However, the Polybessurus-like fossils are rare in quantity and generally fragmentary and structureless in stromatolitic clots and spotted clots. Such taphonomic features are likely interpreted as the early decomposition by heterotrophic bacteria in an oxygen-depleted microenvironment caused by rapid accumulations of organic matter in the calm water. More enrichments of 13C in the laminae of stromatolite and in the clots of stromatolitic thrombolite and spotted thrombolite than in adjacent interstitial matrixes signify the photosynthesis-dominated isotopic fractionation during the growth of microbial communities. Rare calcimicrobial structures but many calcite crystal fans were found in the 13C-depleted digitate clots. These phenomena indicate that seawater on the carbonate platform was 12C-enriched and supersaturated, accelerating carbonate precipitations and decompositions of organic matter within the microbial community. Different preservations of the Polybessurus-like fossil revealed the complicated microbially-dominated sedimentation and post-depositional diagenesis in the abnormal seawater after the catastrophe.https://doi.org/10.1186/s42501-021-00091-3MicrobialiteCalcimicrobeCarbon isotopeDiagenesisEnd-Permian mass extinctionSouth China Block |
| spellingShingle | Xi-Yang Zhang Yue Li Guan Wang Hong-Qiang Yang Different accretion and diagenetic patterns within the fabrics of the Permian–Triassic boundary microbialites on the Leye isolated carbonate platform, South China Block Journal of Palaeogeography Microbialite Calcimicrobe Carbon isotope Diagenesis End-Permian mass extinction South China Block |
| title | Different accretion and diagenetic patterns within the fabrics of the Permian–Triassic boundary microbialites on the Leye isolated carbonate platform, South China Block |
| title_full | Different accretion and diagenetic patterns within the fabrics of the Permian–Triassic boundary microbialites on the Leye isolated carbonate platform, South China Block |
| title_fullStr | Different accretion and diagenetic patterns within the fabrics of the Permian–Triassic boundary microbialites on the Leye isolated carbonate platform, South China Block |
| title_full_unstemmed | Different accretion and diagenetic patterns within the fabrics of the Permian–Triassic boundary microbialites on the Leye isolated carbonate platform, South China Block |
| title_short | Different accretion and diagenetic patterns within the fabrics of the Permian–Triassic boundary microbialites on the Leye isolated carbonate platform, South China Block |
| title_sort | different accretion and diagenetic patterns within the fabrics of the permian triassic boundary microbialites on the leye isolated carbonate platform south china block |
| topic | Microbialite Calcimicrobe Carbon isotope Diagenesis End-Permian mass extinction South China Block |
| url | https://doi.org/10.1186/s42501-021-00091-3 |
| work_keys_str_mv | AT xiyangzhang differentaccretionanddiageneticpatternswithinthefabricsofthepermiantriassicboundarymicrobialitesontheleyeisolatedcarbonateplatformsouthchinablock AT yueli differentaccretionanddiageneticpatternswithinthefabricsofthepermiantriassicboundarymicrobialitesontheleyeisolatedcarbonateplatformsouthchinablock AT guanwang differentaccretionanddiageneticpatternswithinthefabricsofthepermiantriassicboundarymicrobialitesontheleyeisolatedcarbonateplatformsouthchinablock AT hongqiangyang differentaccretionanddiageneticpatternswithinthefabricsofthepermiantriassicboundarymicrobialitesontheleyeisolatedcarbonateplatformsouthchinablock |