The Muse oil-shale beds (Muse OSB) of the Permian Muse Formation in the Autun Basin (France) have received attention for their exceptionally well-preserved flora and fauna throughout many decades. Recent CA-ID-TIMS U/Pb radiometric datings place the Muse section in the lower Asselian (~298.6 Ma), le...
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Académie des sciences
2025-06-01
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| Series: | Comptes Rendus. Géoscience |
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| Online Access: | https://comptes-rendus.academie-sciences.fr/geoscience/articles/10.5802/crgeos.294/ |
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| author | Juncal, Manuel Antonio Barreiro, Iván Rodriguez Galtier, Jean Broutin, Jean Pellenard, Pierre Steyer, Jean-Sébastien Diez, José Bienvenido Gand, Georges |
| author_facet | Juncal, Manuel Antonio Barreiro, Iván Rodriguez Galtier, Jean Broutin, Jean Pellenard, Pierre Steyer, Jean-Sébastien Diez, José Bienvenido Gand, Georges |
| author_sort | Juncal, Manuel Antonio |
| collection | DOAJ |
| description | The Muse oil-shale beds (Muse OSB) of the Permian Muse Formation in the Autun Basin (France) have received attention for their exceptionally well-preserved flora and fauna throughout many decades. Recent CA-ID-TIMS U/Pb radiometric datings place the Muse section in the lower Asselian (~298.6 Ma), leading to a re-examination of the palynoflora using an alternative palynological method. Twelve productive samples provide a detailed taxonomic and quantitative evaluation of the palynoflora. The new data revealed now two distinct palynological assemblages, Muse-A in the lower part and Muse-B in the middle-upper part of the Muse section, assigned to a peat swamp forest environment dominated by cordaitalean conifers, alongside medullosalean cycads and callistophytalean seed ferns, with an undergrowth of lycophytes and ferns. Additionally, a forest dominated by walchian conifers (Voltziales) would be present but more distant from the lake. Vegetation dynamics between these associations are generally stable, except for an increase in Cordaitales at the expense of Voltziales. This variation, observed throughout the Autun Basin, seems to be affected by seasonal climate-driven changes. The co-occurrence in both assemblages of Permian xerophytic elements accompanied by Carboniferous wetland flora suggests a seasonally dry climate, supporting hygrophyte plant survival, persisting for at least 300 ky after the Carboniferous–Permian boundary. The phytoplankton community consisted of freshwater green algae, increasing towards the upper part of the section, coeval with increased explosive volcanic activity. Wind-transported volcanic ash likely provided nutrient input, enhancing lacustrine phytoplankton growth. |
| format | Article |
| id | doaj-art-3502efe369ac4d4e847f633f98baa498 |
| institution | Kabale University |
| issn | 1778-7025 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | Académie des sciences |
| record_format | Article |
| series | Comptes Rendus. Géoscience |
| spelling | doaj-art-3502efe369ac4d4e847f633f98baa4982025-08-20T03:58:11ZengAcadémie des sciencesComptes Rendus. Géoscience1778-70252025-06-01357G124526310.5802/crgeos.29410.5802/crgeos.294Juncal, Manuel Antonio0https://orcid.org/0000-0002-3344-1342Barreiro, Iván Rodriguez1https://orcid.org/0000-0002-0938-662XGaltier, Jean2Broutin, Jean3Pellenard, Pierre4https://orcid.org/0000-0002-1452-2569Steyer, Jean-Sébastien5https://orcid.org/0000-0003-1835-7852Diez, José Bienvenido6https://orcid.org/0000-0001-5739-7270Gand, Georges7CINTECX, Grupo de Tecnología Energética (GTE), Universidade de Vigo, 36310 Vigo, SpainCentro de Investigación Mariña, Universidade de Vigo, BASAN, 36310 Vigo, Spain; Departamento de Xeociencias Mariñas e Ordenación do Territorio, Universidade de Vigo, 36310 Vigo, Spain; Museum of Nature South Tyrol, Bindergasse/Via Bottai 1, 39100 Bozen/Bolzano (BZ), ItalyCIRAD, AMAP TA 40/PS2, Boulevard de la Lironde, F-34398 Montpellier, FranceSorbonne Universités, Paléobotanique & Paléoécologie, CR2P, UPMC Paris 6-MNHN-CNRS, F-75005 Paris, FranceUniversité Bourgogne Europe, Biogéosciences UMR CNRS/uB/EPHE 6282, 6 boulevard Gabriel, 21000 Dijon, FranceCentre de Recherches en Paléontologie de Paris, UMR 7207, CNRS-MNHN-SU, Muséum national d’Histoire naturelle, CP 38, 8 rue Buffon, 75005 Paris, FranceCentro de Investigación Mariña, Universidade de Vigo, BASAN, 36310 Vigo, Spain; Departamento de Xeociencias Mariñas e Ordenación do Territorio, Universidade de Vigo, 36310 Vigo, SpainUniversité Bourgogne Europe, Biogéosciences UMR CNRS/uB/EPHE 6282, 6 boulevard Gabriel, 21000 Dijon, FranceThe Muse oil-shale beds (Muse OSB) of the Permian Muse Formation in the Autun Basin (France) have received attention for their exceptionally well-preserved flora and fauna throughout many decades. Recent CA-ID-TIMS U/Pb radiometric datings place the Muse section in the lower Asselian (~298.6 Ma), leading to a re-examination of the palynoflora using an alternative palynological method. Twelve productive samples provide a detailed taxonomic and quantitative evaluation of the palynoflora. The new data revealed now two distinct palynological assemblages, Muse-A in the lower part and Muse-B in the middle-upper part of the Muse section, assigned to a peat swamp forest environment dominated by cordaitalean conifers, alongside medullosalean cycads and callistophytalean seed ferns, with an undergrowth of lycophytes and ferns. Additionally, a forest dominated by walchian conifers (Voltziales) would be present but more distant from the lake. Vegetation dynamics between these associations are generally stable, except for an increase in Cordaitales at the expense of Voltziales. This variation, observed throughout the Autun Basin, seems to be affected by seasonal climate-driven changes. The co-occurrence in both assemblages of Permian xerophytic elements accompanied by Carboniferous wetland flora suggests a seasonally dry climate, supporting hygrophyte plant survival, persisting for at least 300 ky after the Carboniferous–Permian boundary. The phytoplankton community consisted of freshwater green algae, increasing towards the upper part of the section, coeval with increased explosive volcanic activity. Wind-transported volcanic ash likely provided nutrient input, enhancing lacustrine phytoplankton growth.https://comptes-rendus.academie-sciences.fr/geoscience/articles/10.5802/crgeos.294/Lacustrine palaeoecosystemCisuralianPalaeobotanical reconstructionLate PalaeozoicExplosive volcanic activity |
| spellingShingle | Juncal, Manuel Antonio Barreiro, Iván Rodriguez Galtier, Jean Broutin, Jean Pellenard, Pierre Steyer, Jean-Sébastien Diez, José Bienvenido Gand, Georges Comptes Rendus. Géoscience Lacustrine palaeoecosystem Cisuralian Palaeobotanical reconstruction Late Palaeozoic Explosive volcanic activity |
| topic | Lacustrine palaeoecosystem Cisuralian Palaeobotanical reconstruction Late Palaeozoic Explosive volcanic activity |
| url | https://comptes-rendus.academie-sciences.fr/geoscience/articles/10.5802/crgeos.294/ |