Ichnological synthesis of the marine units of the Neuquén Basin, new data and future perspectives
In this paper the ichnology of the marine intervals of the Neuquén Basin is reviewed, taking into account an stratigraphic framework and discussing previous works on ichnology that contain some ichnogenus (Lapispira) that are firstly documented in South America in Jurassic rocks of the Río Atuel are...
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2009 |
| País: | Argentina |
| Institución: | Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales |
| Repositorio: | Biblioteca Digital (UBA-FCEN) |
| Idioma: | inglés |
| OAI Identifier: | paperaa:paper_00044822_v65_n2_p362_Pazos |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00044822_v65_n2_p362_Pazos |
| Access Level: | acceso abierto |
| Palabra clave: | Cretaceous Ichnology Marine Neuquén Swimming traces fossil record ichnology paleogeography paleontology trace fossil trackway Argentina Neuquen Basin Arthropoda Asteriacites Bergaueria Bivalvia Diplichnites Diplocraterion Lockeia Palaeophycus Teichichnus Tellinoidea Thalassinoides Vertebrata |
| Sumario: | In this paper the ichnology of the marine intervals of the Neuquén Basin is reviewed, taking into account an stratigraphic framework and discussing previous works on ichnology that contain some ichnogenus (Lapispira) that are firstly documented in South America in Jurassic rocks of the Río Atuel area, and other ichnogenera that constitute well preserved records in the Jurassic tidal influenced deltas of the Lajas Formation. The trace fossil record includes Asterosoma, Asteriacites, Dactyloidites, Diplocraterion, Gyrochorte, Palaeophycus, Polykladichnus, Schaubcilindrichnus, Siphonichnus, Thalassinoides, Teichichnus and rare traces in shallow marine deposits like Helmin-thorhaphe and root traces indicative of a very complex facies scheme. A special mention deserves the traces from the carbonates of the La Manga Formation at Bardas Blancas, that contain ichnogenera like Dactyloidites, Gyrochorte, Jamerosonichnites and Thalassinoides recorded in tempestites. The Lower Cretaceous record documented in the Mulichinco and Agrio Formation is composed of Asteriacites, Gyrochorte, Lockeia, Ophiomorpha, and possibly Bergaueria, documented in the Mulichinco Formation at Vega de Escalone locality. Other ichnofossils described in the Agrio Formation are Gyrochorte, Ophiomorpha, Thalassinoides, Teichichnus among others of dubious assignation recorded at Bajada del Agrio and other areas of the basin. New material coming from both units includes subaqueous vertebrate scratchs (Characichnos?) both from Vega de Escalone and Puerta Curaco. Arthropod trackways include both some with differentiated (Diplichnites?) and other specimen with undifferentiated appendages. In the case of the Agrio Formation at Cerro Rayoso, teropod tracks are indicatives of subaerial exposure in sections expected to be fully marine. Complex traces assigned to Hillichnus produced by tellinacean bivalves are the only record of such bivalves in the basin. Those ichnogenera are good examples that precede body fossil records and along with the scratch marks suggest very shallow and occasional subaerial exposition in areas of the basin unexpected according to paleogeographic maps. Finally a brief analysis of the further work in the turbidites of the Molles Formation or the exploration of bioerosion and meiofauna records suggest that the knowledge about the ichnology of the Neuquén Basin is in its infancy if it is compared with the stratigraphic, paleontologic (biostratigraphic) and sedimentologic studies and also remains unexplored related to changes in permeability of reservoirs of bioturbated deposits documented from cores. |
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