|Ostracods and sedimentology of the Frasnian-Famennian boundary beds in the Kostomloty section (Holy Cross Mountains, Poland)|
Casier, J.-G.; Devleeschouwer, X.; Lethiers, F.; Préat, A.; Grzegorz, R. (2000). Ostracods and sedimentology of the Frasnian-Famennian boundary beds in the Kostomloty section (Holy Cross Mountains, Poland). Bull. Kon. Belg. Inst. Natuurwet. Aardwet. = Bull. - Inst. r. sci. nat. Belg., Sci. Terre 70: 53-74
In: Bulletin van het Koninklijk Belgisch Instituut voor Natuurwetenschappen. Aardwetenschappen = Bulletin de l'Institut Royal des Sciences Naturelles de Belgique. Sciences de la Terre. KBIN: Brussel. ISSN 0374-6291
Geological time > Phanerozoic > Paleozoic > Palaeozoic > Devonian > Devonian, Upper > Famennian
Geological time > Phanerozoic > Paleozoic > Palaeozoic > Devonian > Devonian, Upper > Frasnian
Poland [Marine Regions]
Ostracods, sedimentology, mass extinction, Late Devonian, Holy Cross Mountains, Poland
|Auteurs|| || Top |
- Casier, J.-G.
- Devleeschouwer, X.
- Lethiers, F.
Sixty-eight ostracod species belonging to the Eifelian ecotype and the majority of which are figured, are recorded from across the Frasnian-Famennian boundary in the Kostomloty quarry, Holy Cross Mountains of Poland. In this 6.5 meter thick section, the ostracod fauna is rich and diverse in the Frasnian, but scarce and poorly diversified in the Famennian. Podocopids, with numerous Bairdiocypridacea and Bairdiacea, dominate in the Frasnian, and palaeocopids (with Kloedenellacea) prevail in the Famennian. Myodocopids are almost absent and metacopids are missing. The ostracods of the Kostomloty quarry indicate a regressive trend ranging from a marine environment below wave base in the late Frasnian, to semi-restricted water conditions in the early Famennian. No assemblage or lithology characteristic of hypoxic water conditions have been recorded from the Kostomloty section.The disappearance of ostracods close to the Frasnian-Famennian boundary is pronounced in the Kostomloty section, and only 6 (8?) species out of 53 occurring in the late Frasnian cross the boundary. However, a total of 12(14?) species survived the Frasnian-Famennian event if "wrongly disappearing species" and "wrongly new arriving species" are taken into account.Sedimentological studies and sequence analyses also point to a recession associated with the Frasnian-Famennian boundary. The fall in sea level, starting at the boundary, has affected very shallow-water, semi-restricted back-shoal environments and has continued and included the erosion of the open-marine fore-shoal facies. This suggests a change of more than ten meters in sea level. After the regression, semi-restricted tidal flats and pre-evaporitic supratidal environments became widely established. On a broad scale, the microfacies curve shows a gradual shift from open-marine waters in the late Frasnian to restricted ones in the early Famennian. The 3rd order sequence boundary emphasizes this transition and the ostracod assemblages as well as those of other organisms (Algae) follow this general pattern. Three new ostracod species are proposed: Coelonelia crassa nov. sp., Sulcella (Postsukella) kostomiotyensis nov. sp. and Bairdia (Rectobairdia) sanctacrucensis nov. sp.