Franceville basin explained

The Franceville Basin is a 1.6–2.1 billion year old sedimentary basin in Gabon. It contains unmetamorphosed sediments.^[1] It is notable for containing the Francevillian Biota, which are possibly the oldest multicellular life known. A natural fission reactor formed there about 1.8 - 2.1 billion years ago.^[2]

Geology

The Franceville Basin covers approximately 25,000 km² and is made up of unmetamorphosed sediment derived mainly from eroded Mesoarchaean tonalite–trondhjemite–granodiorites.^[3] It is over a kilometer thick, with various sources claiming 2.5-4 kilometers as the maximum depth. Around 1.8-2.1 billion years ago a natural fission reactor formed, nicknamed the "Oklo reactor". The resulting fission by-products were held in place by a clay layer.

See also

• Francevillian biota
• Francevillian B Formation

Notes and References

1. Bankole. Olabode M.. El Albani. Abderrazak. Meunier. Alain. Gauthier-Lafaye. François. October 2015. Textural and paleo-fluid flow control on diagenesis in the Paleoproterozoic Franceville Basin, South Eastern, Gabon. Precambrian Research. en. 268. 115–134. 10.1016/j.precamres.2015.07.008.
2. Gauthier-Lafaye. F.. Holliger. P.. Blanc. P. -L.. 1996-12-01. 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. en. 60. 23. 4831–4852. 10.1016/S0016-7037(96)00245-1. 0016-7037.
3. Bankole . Olabode M. . El Albani . Abderrazak . Munier . Alain . Poujol . Marc . Bekker . Andrey . 15 September 2020 . Elemental geochemistry and Nd isotope constraints on the provenance of the basal siliciclastic succession of the middle Paleoproterozoic Francevillian Group, Gabon . . 348 . 105874 . 10.1016/j.precamres.2020.105874 . 224896274 . 13 November 2022. free .