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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 where it gets its name from. The formation was deposited between 2.14-2.08 Ga (billion years ago) in the [[Palaeoproterozoic]],<ref name="Nanoscale">{{cite journal | url=https://www.sciencedirect.com/science/article/abs/pii/S0301926817302437 | doi=10.1016/j.precamres.2017.08.024 | title=Nanoscale analysis of preservation of ca. 2.1 Ga old Francevillian microfossils, Gabon | year=2017 | last1=Lekele Baghekema | first1=Stellina G. | last2=Lepot | first2=Kevin | last3=Riboulleau | first3=Armelle | last4=Fadel | first4=Alexandre | last5=Trentesaux | first5=Alain | last6=El Albani | first6=Abderrazak | journal=Precambrian Research | volume=301 | pages=1–18 | bibcode=2017PreR..301....1L }}</ref> 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.<ref name="Franceville1">{{cite journal | doi=10.1371/journal.pone.0099438 | doi-access=free | title=The 2.1 Ga Old Francevillian Biota: Biogenicity, Taphonomy and Biodiversity | year=2014 | last1=El Albani | first1=Abderrazak | last2=Bengtson | first2=Stefan | last3=Canfield | first3=Donald E. | last4=Riboulleau | first4=Armelle | last5=Rollion Bard | first5=Claire | last6=MacChiarelli | first6=Roberto | last7=Ngombi Pemba | first7=Lauriss | last8=Hammarlund | first8=Emma | last9=Meunier | first9=Alain | last10=Moubiya Mouele | first10=Idalina | last11=Benzerara | first11=Karim | last12=Bernard | first12=Sylvain | last13=Boulvais | first13=Philippe | last14=Chaussidon | first14=Marc | last15=Cesari | first15=Christian | last16=Fontaine | first16=Claude | last17=Chi-Fru | first17=Ernest | last18=Garcia Ruiz | first18=Juan Manuel | last19=Gauthier-Lafaye | first19=François | last20=Mazurier | first20=Arnaud | last21=Pierson-Wickmann | first21=Anne Catherine | last22=Rouxel | first22=Olivier | last23=Trentesaux | first23=Alain | last24=Vecoli | first24=Marco | last25=Versteegh | first25=Gerard J. M. | last26=White | first26=Lee | last27=Whitehouse | first27=Martin | last28=Bekker | first28=Andrey | journal=PLOS ONE | volume=9 | issue=6 | pages=e99438 | pmid=24963687 | pmc=4070892 | bibcode=2014PLoSO...999438E }}</ref> The ''Francevillian B Formation'' is important to the field of [[palaeontology]] because it contains fossil material of possible [[Eukaryote|eukaryotic organisms]] from around 2.1 Ga which have been informally dubbed the "''[[Francevillian biota]]''" or "''[[Gabonionta]]''". This biota takes on the appearance of a multitude of forms such as discs with ruffled ridges, ruffled blobs, "stalked/tailed flowers" and strings of beads that were interpreted by [[Abderrazak El Albani]] as being akin to that of [[Dictyostelium]] [[slime moulds]].<ref name="El Albani 2014">{{cite journal|last1=El Albani|first1=Abderrazak|last2=Bengtson|first2=Stefan|last3=Canfield|first3=Donald E.|last4=Riboulleau|first4=Armelle|last5=Rollion Bard|first5=Claire|last6=Macchiarelli|first6=Roberto|display-authors=etal|title=The 2.1 Ga Old Francevillian Biota: Biogenicity, Taphonomy and Biodiversity|journal=PLOS ONE|year= 2014|volume=9|issue=6|pages=e99438|doi=10.1371/journal.pone.0099438|bibcode = 2014PLoSO...999438E|pmid=24963687|pmc=4070892|doi-access=free}}</ref> El Albani also described a multitude of "strings of beads" which appear to have been similar to those found on the "stalked flowers" that he described along with the other biota which have been compared to the far younger [[Beltanelliformis]].<ref name="El Albani 2014"/> The fossils of the biota from the ''Francevillian B formation'' are assumed to have had primitive ''cell-to-cell'' communication, as they are older than the oldest known evidence for the existence of multicellularity in the fossil record <ref name="Sébe-Pedrós">{{cite journal|last=Sebe-Pedros|first=A.|author2=Roger, A. J. |author3=Lang, F. B. |author4=King, N. |author5= Ruiz-Trillo, I. |title=Ancient origin of the integrin-mediated adhesion and signaling machinery|journal=Proceedings of the National Academy of Sciences|year=2010|volume=107|issue=22|pages=10142–10147|doi=10.1073/pnas.1002257107|bibcode=2010PNAS..10710142S |pmid=20479219 |pmc=2890464|doi-access=free}}</ref> |
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 where it gets its name from. The formation was deposited between 2.14-2.08 Ga (billion years ago) in the [[Palaeoproterozoic]],<ref name="Nanoscale">{{cite journal | url=https://www.sciencedirect.com/science/article/abs/pii/S0301926817302437 | doi=10.1016/j.precamres.2017.08.024 | title=Nanoscale analysis of preservation of ca. 2.1 Ga old Francevillian microfossils, Gabon | year=2017 | last1=Lekele Baghekema | first1=Stellina G. | last2=Lepot | first2=Kevin | last3=Riboulleau | first3=Armelle | last4=Fadel | first4=Alexandre | last5=Trentesaux | first5=Alain | last6=El Albani | first6=Abderrazak | journal=Precambrian Research | volume=301 | pages=1–18 | bibcode=2017PreR..301....1L }}</ref> 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.<ref name="Franceville1">{{cite journal | doi=10.1371/journal.pone.0099438 | doi-access=free | title=The 2.1 Ga Old Francevillian Biota: Biogenicity, Taphonomy and Biodiversity | year=2014 | last1=El Albani | first1=Abderrazak | last2=Bengtson | first2=Stefan | last3=Canfield | first3=Donald E. | last4=Riboulleau | first4=Armelle | last5=Rollion Bard | first5=Claire | last6=MacChiarelli | first6=Roberto | last7=Ngombi Pemba | first7=Lauriss | last8=Hammarlund | first8=Emma | last9=Meunier | first9=Alain | last10=Moubiya Mouele | first10=Idalina | last11=Benzerara | first11=Karim | last12=Bernard | first12=Sylvain | last13=Boulvais | first13=Philippe | last14=Chaussidon | first14=Marc | last15=Cesari | first15=Christian | last16=Fontaine | first16=Claude | last17=Chi-Fru | first17=Ernest | last18=Garcia Ruiz | first18=Juan Manuel | last19=Gauthier-Lafaye | first19=François | last20=Mazurier | first20=Arnaud | last21=Pierson-Wickmann | first21=Anne Catherine | last22=Rouxel | first22=Olivier | last23=Trentesaux | first23=Alain | last24=Vecoli | first24=Marco | last25=Versteegh | first25=Gerard J. M. | last26=White | first26=Lee | last27=Whitehouse | first27=Martin | last28=Bekker | first28=Andrey | journal=PLOS ONE | volume=9 | issue=6 | pages=e99438 | pmid=24963687 | pmc=4070892 | bibcode=2014PLoSO...999438E }}</ref> The ''Francevillian B Formation'' is important to the field of [[palaeontology]] because it contains fossil material of possible [[Eukaryote|eukaryotic organisms]] from around 2.1 Ga which have been informally dubbed the "''[[Francevillian biota]]''" or "''[[Gabonionta]]''". This biota takes on the appearance of a multitude of forms such as discs with ruffled ridges, ruffled blobs, "stalked/tailed flowers" and strings of beads that were interpreted by [[Abderrazak El Albani]] as being akin to that of [[Dictyostelium]] [[slime moulds]].<ref name="El Albani 2014">{{cite journal|last1=El Albani|first1=Abderrazak|last2=Bengtson|first2=Stefan|last3=Canfield|first3=Donald E.|last4=Riboulleau|first4=Armelle|last5=Rollion Bard|first5=Claire|last6=Macchiarelli|first6=Roberto|display-authors=etal|title=The 2.1 Ga Old Francevillian Biota: Biogenicity, Taphonomy and Biodiversity|journal=PLOS ONE|year= 2014|volume=9|issue=6|pages=e99438|doi=10.1371/journal.pone.0099438|bibcode = 2014PLoSO...999438E|pmid=24963687|pmc=4070892|doi-access=free}}</ref> El Albani also described a multitude of "strings of beads" which appear to have been similar to those found on the "stalked flowers" that he described along with the other biota which have been compared to the far younger [[Beltanelliformis]].<ref name="El Albani 2014"/> The fossils of the biota from the ''Francevillian B formation'' are assumed to have had primitive ''cell-to-cell'' communication, as they are older than the oldest known evidence for the existence of multicellularity in the fossil record <ref name="Sébe-Pedrós">{{cite journal|last=Sebe-Pedros|first=A.|author2=Roger, A. J. |author3=Lang, F. B. |author4=King, N. |author5= Ruiz-Trillo, I. |title=Ancient origin of the integrin-mediated adhesion and signaling machinery|journal=Proceedings of the National Academy of Sciences|year=2010|volume=107|issue=22|pages=10142–10147|doi=10.1073/pnas.1002257107|bibcode=2010PNAS..10710142S |pmid=20479219 |pmc=2890464|doi-access=free}}</ref> |
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Revision as of 12:19, 6 May 2023
| Francevillian B Formation | |
|---|---|
| Stratigraphic range: Palaeoproterozoic (Rhyacian) | |
| File:Francevillian biota.jpg 2 Members of the Francevillian biota. | |
| 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 where it gets its name from. 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 Francevillian B Formation is important to the field of palaeontology because it contains fossil material of possible eukaryotic organisms from around 2.1 Ga which have been informally dubbed the "Francevillian biota" or "Gabonionta". This biota takes on the appearance of a multitude of forms such as discs with ruffled ridges, ruffled blobs, "stalked/tailed flowers" and strings of beads that were interpreted by Abderrazak El Albani as being akin to that of Dictyostelium slime moulds.[3] El Albani also described a multitude of "strings of beads" which appear to have been similar to those found on the "stalked flowers" that he described along with the other biota which have been compared to the far younger Beltanelliformis.[3] The fossils of the biota from the Francevillian B formation are assumed to have had primitive cell-to-cell communication, as they are older than the oldest known evidence for the existence of multicellularity in the fossil record [4]
Significance and History
The Francevillian B. Formation was discovered by a team of palaeontologists led by the French-Moroccan palaeontologist Abderrazak El Albani in 2010 with assistance from the University of Poitiers.[5] The team revolutionized ideas about the earliest life on Earth, because the earliest known geochemical evidence dates back as far as 3.7 Ga, and discovered a biota made of macroscopic multicellular organisms which were dated to be around 2.1 billion years old that were informally named the "Francevillian biota".[5] However, these fossils had multiple interpretations and were at one time thought of as being microbial mats similar to those found in the Ediacaran. A combination of scanning electron microscopy, petrographic analyses, Raman spectroscopy and analyses of the elements of the carbon-rich laminae and microtexure from the fossils concluded that the biota of the Francevillian B Formation were of organic origin.[6] The Franceville basin also has another basin near it, the Lastourville basin.
A 2023 paper published by an international team led by El Albani unearthed new disc-shaped Planktonic Francevillian fossils in 2023.[7] The fossils were found to definitively be of Eukaryotic origin, placing the Francevillian biota as being somewhat Eukaryotic (however, the definitive classification is still debated). The fossils were found in the Francevillian deposits of Moulendé, Gabon and the team identified twice as much zinc isotopes than the surrounding sedimentary deposit. Although the oldest planktonic organisms were thought to have emerged 570 million years ago (Ediacaran), the Francevillian fossils now pushes the time range 1500 million years earlier.[7]
Geology
The Francevillian Formation has recently been discovered to contain traces of uranium. The Francevillian basin itself already contained Oklo Mine, a natural nuclear reactor.[8][9][10][11] However, the formation also witnessed a former system of petroleum which showed major amounts of uranium associated with organic matter. Several episodes of oil generation, migration and fluid mixing along with hydrofracturing are the cause of the uranium mineralization.[11] During burial of the formation, its multiple black shales were heated and in doing so expelled hydrocarbons that migrated into underlying sandstones, with the first episode of the oil migration being synchronous along with a silicification event that derived into a hot and low salinity fluid which is proven by fluid inclusions trapped in overgrowths of quartz.[11] However, the second episode of the oil migration was contemporaneous and has quartz dissolution with the episode being characterized by the mixing of hydrocarbons and oxidizing the uranium-bearing brine which in turn caused the precipitation of UO2 to be included in the oils. In the third and final episode of oil migration within the Francevillian B formation, oil-to-gas conversion generated overly-pressured gas trapped with uraniferous bitumen nodules in pores. Changes in the stress regime probably favoured radial hydrofracturing around the bitumen nodules as well as the subsequent development of a somewhat pervasive micro-fracture network.[11]
Biota
The Francevillian B formation is most notable for its significant fossil findings of the informally dubbed "Francevillian biota". These centimetre-sized discs include a wide variety of shapes, which include elongate, lobate and rod-shaped "strings of beads" that are often associated with one another and are ubiquitous to the formation.[2] With the combination of Microtomography, Geochemistry and analysing sediments has revealed that this biota fossilized in the early stages of diagenesis. A rise in Oxygen levels followed up with the emergence of this biota and is further evidence to support the idea of surface Oxygenation being able to evolutionary and ecology expansion of complex macro and megascopic life, with there also being the inclusion of organic-walled Acritarchs.[2] The reports of these centimetre-sized pyritized fossils from Gabon have opened a new window on the vision of the fossil record and also shows new evidence for the existence of some of the oldest known multi-cellular organisms in the fossil record.[2] Grypania spiralis may have also been a Eukaryote from about 2 Billion years ago.[12] Grypania and Horodyskia (although the latter is much younger than the former and younger than the Francevillian Biota) are also from a similar timeframe (similar as in appeared in a timeframe which is similar to the timeframe in which the Francevillian biota appeared) as the Francevillian biota, with Grypania being from around 2.0-2.1 GA[13][5] and Horodyskia being dated to about 1.5-0.9 GA.[14] The somewhat similarly aged, 1 millimeter (0.039 in) in length, urn-shaped fossils of Diskagma buttonii were evidence for the earliest life on land and have been dated to around 2200 MA.[15]
The Francevillian biota are, in part with some geochemical traces of organic matter from Western Greenland, part of the earth's earliest probable life forms and provided crucial steps in the evolution of Eukaryotes.[2][5] However, the biota seen in the Francevillian Formation sparked some debating on their full taxonomic affinity, as well as the evolution and origin of organisms and modern-day Phyla. The interpretation of this biota as being colonies of Archaea (like Grypania and Horodyskia) has not been accepted because of their complex morphology that is much more complex than Grypania.[5] The up-to 17 centimeters (6.7 in) 450 specimens can almost be attributed to the same body plan, however some are reminiscent of Flatworms. Although the fossils are share unique characteristics and often can be mistaken with each other, it's currently unknown if they represent the life stages of one organism in particular, or if they represent several individual species and taxa. The fossils all have a common central spherical element present in all of them which would often be flexible and exhibits a tiny amount of folds.[5] Although it's most commonly distorted and folded in fossils.[5]
See also
References
- ^ 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.
- ^ a b c d e 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.
- ^ a b El Albani, Abderrazak; Bengtson, Stefan; Canfield, Donald E.; Riboulleau, Armelle; Rollion Bard, Claire; Macchiarelli, Roberto; et al. (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.
- ^ Sebe-Pedros, A.; Roger, A. J.; Lang, F. B.; King, N.; Ruiz-Trillo, I. (2010). "Ancient origin of the integrin-mediated adhesion and signaling machinery". Proceedings of the National Academy of Sciences. 107 (22): 10142–10147. Bibcode:2010PNAS..10710142S. doi:10.1073/pnas.1002257107. PMC 2890464. PMID 20479219.
- ^ a b c d e f g Experiment Life – the Gabonionta. (Press Release). 4 March 2014. Naturhistorisches Museum Wien
- ^ Aubineau, Jérémie; El Albani, Abderrazak; Chi Fru, Ernest; Gingras, Murray; Batonneau, Yann; Buatois, Luis A.; Geffroy, Claude; Labanowski, Jérôme; Laforest, Claude; Lemée, Laurent; Mángano, Maria G.; Meunier, Alain; Pierson-Wickmann, Anne-Catherine; Recourt, Philippe; Riboulleau, Armelle; Trentesaux, Alain; Konhauser, Kurt O. (2018). "Unusual microbial mat-related structural diversity 2.1 billion years ago and implications for the Francevillian biota". Geobiology. 16 (5): 476–497. doi:10.1111/gbi.12296. PMID 29923673. S2CID 49316052.
- ^ a b "Coopération scientifique France-Gabon: Découverte des plus vieux eucaryotes planctoniques macroscopiques au Gabon" (PDF). 2 May 2023.
- ^ Meshik, A. P. (November 2005). "The Workings of an Ancient Nuclear Reactor". Scientific American. 293 (5): 82–6, 88, 90–1. Bibcode:2005SciAm.293e..82M. doi:10.1038/scientificamerican1105-82. PMID 16318030.
- ^ Mervine, Evelyn (13 July 2011). "Nature's Nuclear Reactors: The 2-Billion-Year-Old Natural Fission Reactors in Gabon, Western Africa". blogs.scientificamerican.com. Retrieved 3 June 2020.
- ^ Gauthier-Lafaye, F.; Holliger, P.; Blanc, P.-L. (1996). "Natural fission reactors in the Franceville Basin, Gabon: a review of the conditions and results of a "critical event" in a geologic system". Geochimica et Cosmochimica Acta. 60 (25): 4831–4852. Bibcode:1996GeCoA..60.4831G. doi:10.1016/S0016-7037(96)00245-1.
- ^ a b c d Lecomte, Andreï; Michels, Raymond; Cathelineau, Michel; Morlot, Christophe; Brouand, Marc; Flotté, Nicolas (2020). "Uranium deposits of Franceville basin (Gabon): Role of organic matter and oil cracking on uranium mineralization". Ore Geology Reviews. 123: 103579. doi:10.1016/j.oregeorev.2020.103579. S2CID 219505204.
- ^ Albani, Abderrazak El; Bengtson, Stefan; Canfield, Donald E.; Bekker, Andrey; MacChiarelli, Roberto; Mazurier, Arnaud; Hammarlund, Emma U.; Boulvais, Philippe; Dupuy, Jean-Jacques; Fontaine, Claude; Fürsich, Franz T.; Gauthier-Lafaye, François; Janvier, Philippe; Javaux, Emmanuelle; Ossa, Frantz Ossa; Pierson-Wickmann, Anne-Catherine; Riboulleau, Armelle; Sardini, Paul; Vachard, Daniel; Whitehouse, Martin; Meunier, Alain (2010). "Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago". Nature. 466 (7302): 100–104. Bibcode:2010Natur.466..100A. doi:10.1038/nature09166. PMID 20596019. S2CID 4331375.
- ^ Han, T. M.; Runnegar, B. (10 July 1992). "Megascopic eukaryotic algae from the 2.1-billion-year-old negaunee iron-formation, Michigan". Science. 257 (5067): 232–235. Bibcode:1992Sci...257..232H. doi:10.1126/science.1631544. ISSN 0036-8075. PMID 1631544.
- ^ Fedonkin, M.A. (March 2003). "The origin of the Metazoa in the light of the Proterozoic fossil record" (PDF). Paleontological Research. 7 (1): 9–41. doi:10.2517/prpsj.7.9. S2CID 55178329. Archived from the original (PDF) on 18 May 2006. Retrieved 2 September 2008.
- ^ Retallack, G.J.; Krull, E.S.; Thackray, G.D.; Parkinson, D. (2013). "Problematic urn-shaped fossils from a Paleoproterozoic (2.2 Ga) paleosol in South Africa". Precambrian Research. 235: 71–87. Bibcode:2013PreR..235...71R. doi:10.1016/j.precamres.2013.05.015.
External links
- For more images of the Francevillian biota, see Experiment Life – the Gabonionta (English version).