La microflore de diatomées au passage mio-pliocène en Corse |
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Authors: | Simona Saint Martin Jean-Paul Saint Martin Jean Ferrandini |
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Institution: | a Laboratoire de paléontologie, université de Bucarest, 1, boulevard Nicolae-Balcescu, Bucarest, Roumanie b Département histoire de la terre, Muséum national d’histoire naturelle, UMR 5143, 8, rue Buffon, 75005 Paris, France c Laboratoire des sciences de la terre, université de Corse, BP 52, 20250 Corte, France |
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Abstract: | The “Aleria formation”, described in northeastern Corsica, consists of siliciclastic deposits referred to a deltaic environment and comprises diatomitic lenses exposed at Casabianda. The Aleria formation fills a depression of the Messinian erosional surface and is overlain by Early Pliocene sediments in several places. This suggests a late Messinian-earliest Pliocene age. Diatom microflora is well-preserved and contains 59 species. Pennates indicate a very large diversity with 54 species, while Centrics are represented only by five species. Diatom assemblages show a relative constant composition along the studied interval. The species Aulacoseiragranulata is the dominant taxon with about 90% in all samples. Taxa are of different salinity classes and different modes of life (planktic, tychoplanktic, benthic, epiphytic…), suggesting multiple environmental factor interactions. The environmental model suggested by sedimentological and biological data led as to assume a pond-like coastal receptacle common in deltaic system. This receptacle was slightly influenced by the close marine waters and was supplied by permanent freshwaters from continental run-off and alluvial sheet. This model based on diatom assemblages provides new data for palaeoenvironmental and chronological interpretations of the so-called Messinian Lago-Mare deposits. |
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Keywords: | Corse Messinien Pliocè ne Assemblages de diatomé es Palé oenvironnement |
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