| Francevillian B Formation | |
|---|---|
| Stratigraphic range: Palaeoproterozoic (Rhyacian) | |
| Type | Geological formation |
| Unit of | Francevillian Basin |
| Area | 25,000 square kilometers (9,700 sq mi) |
| Lithology | |
| Primary | Black Shale |
| Location | |
| Region | East-central Gabon |
| Country |  Gabon |
| Extent | 35,000 kilometers (22,000 mi) |
| Type section | |
| Named for | Franceville, a nearby town |
| Named by | Abderrazak El Albani |
 Map of the Geology of the Franceville basin | |
| Part of a series on |
| The Francevillian basin |
|---|
 |
The Francevillian B Formation, also known as the Francevillian Formation or FB2 in scientific research, is a geologic formation of black shale provinces close to the town of Franceville, Gabon from which it gets its name. The formation was deposited between 2.14-2.08 Ga (billion years ago) in the Palaeoproterozoic,[1] and, uniquely, has not experienced any thermal overprinting due to diagenesis after burial nor significant metamorphism since it was deposited, unlike other formations deposited around the same time.[2] The formation contains possible fossils, including the macroscopic "Francevillian Biota", which has been suggested by some authors to represent the oldest known multicellular organisms,[3][4] though other authors have questioned the supposed biological origin of the structures, and have suggested that they may instead be inorganic, such as artifacts of diagenesis.[5][6]
- ^ Lekele Baghekema, Stellina G.; Lepot, Kevin; Riboulleau, Armelle; Fadel, Alexandre; Trentesaux, Alain; El Albani, Abderrazak (2017). "Nanoscale analysis of preservation of ca. 2.1 Ga old Francevillian microfossils, Gabon". Precambrian Research. 301: 1–18. Bibcode:2017PreR..301....1L. doi:10.1016/j.precamres.2017.08.024.
- ^ El Albani, Abderrazak; Bengtson, Stefan; Canfield, Donald E.; Riboulleau, Armelle; Rollion Bard, Claire; MacChiarelli, Roberto; Ngombi Pemba, Lauriss; Hammarlund, Emma; Meunier, Alain; Moubiya Mouele, Idalina; Benzerara, Karim; Bernard, Sylvain; Boulvais, Philippe; Chaussidon, Marc; Cesari, Christian; Fontaine, Claude; Chi-Fru, Ernest; Garcia Ruiz, Juan Manuel; Gauthier-Lafaye, François; Mazurier, Arnaud; Pierson-Wickmann, Anne Catherine; Rouxel, Olivier; Trentesaux, Alain; Vecoli, Marco; Versteegh, Gerard J. M.; White, Lee; Whitehouse, Martin; Bekker, Andrey (2014). "The 2.1 Ga Old Francevillian Biota: Biogenicity, Taphonomy and Biodiversity". PLOS ONE. 9 (6): e99438. Bibcode:2014PLoSO...999438E. doi:10.1371/journal.pone.0099438. PMC 4070892. PMID 24963687.
- ^ El Albani, Abderrazak; Bengtson, Stefan; Canfield, Donald E.; Bekker, Andrey; Macchiarelli, Roberto; Mazurier, Arnaud; Hammarlund, Emma U.; et al. (2010). "Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago" (PDF). Nature. 466 (7302): 100–104. Bibcode:2010Natur.466..100A. doi:10.1038/nature09166. PMID 20596019. S2CID 4331375.[permanent dead link]
- ^ El Albani, Abderrazak (2023). "A search for life in Palaeoproterozoic marine sediments using Zn isotopes and geochemistry". Earth and Planetary Science Letters. 623: 118169. Bibcode:2023E&PSL.61218169E. doi:10.1016/j.epsl.2023.118169. S2CID 258360867.
- ^ Javaux, Emmanuelle J.; Lepot, Kevin (January 2018). "The Paleoproterozoic fossil record: Implications for the evolution of the biosphere during Earth's middle-age". Earth-Science Reviews. 176: 68–86. Bibcode:2018ESRv..176...68J. doi:10.1016/j.earscirev.2017.10.001. hdl:20.500.12210/62416. S2CID 37069547.
The identity of the [Francevillian biota] macrostructures remains unknown and their biogenicity is questionable
- ^ Fakhraee, Mojtaba; Tarhan, Lidya G.; Reinhard, Christopher T.; Crowe, Sean A.; Lyons, Timothy W.; Planavsky, Noah J. (May 2023). "Earth's surface oxygenation and the rise of eukaryotic life: Relationships to the Lomagundi positive carbon isotope excursion revisited". Earth-Science Reviews. 240: 104398. Bibcode:2023ESRv..24004398F. doi:10.1016/j.earscirev.2023.104398. S2CID 257761993.