Francevillian B Formation
Black shale named after Franceville, Gabon / From Wikipedia, the free encyclopedia
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 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]
Francevillian B Formation | |
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Stratigraphic range: Palaeoproterozoic (Rhyacian) 2140–2080 Ma | |
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 |