Quebrada de Talacasto section, cephalopods: Darriwilian, Argentina
collected by M. S. Beresi
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Cephalopoda
- Orthocerida
- Proteoceratidae
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Gangshanoceras sp.
Zou 1988
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1 specimen | |||||||||
| PI-IANIGLA No. 937 Ta 6 | ||||||||||
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Cephalopoda
- Orthocerida
- Baltoceratidae
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Eosomichelinoceras baldisii n. sp.
Kröger et al. 2007
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1 specimen | |||||||||
| PI-IANIGLA No. 923 Ta 10 (type) | ||||||||||
| see common names | ||||||||||
Geography
| Country: | Argentina | State/province: | San Juan |
| Coordinates: | 31.1° South, 68.6° West (view map) | ||
| Paleocoordinates: | 34.5° South, 133.0° West | ||
| Basis of coordinate: | based on nearby landmark | ||
| Geographic resolution: | small collection |
Time
| Period: | Ordovician | Epoch: | Middle Ordovician |
| Stage: | Darriwilian | 10 m.y. bin: | Ordovician 3 |
| Key time interval: | Darriwilian | ||
| Age range of interval: | 467.30000 - 458.40000 m.y. ago |
Stratigraphy
| Formation: | San Juan | ||||
| Stratigraphic resolution: | member | ||||
| Stratigraphy comments: Eoplacognathus variabilis to E. suecicus Zone, upper member of the San Juan Formation"; both conodont zones correspond to the middle part of Darriwilian stage (see http://www.nhm.uio.no/norges/timescale/9b_Lower_Paleozoic_Sept08.pdf) | |||||
Lithology and environment
| Primary lithology: | nodular "limestone" | ||
| Includes fossils? | Y | ||
| Environment: | open shallow subtidal | Tectonic setting: | passive margin |
| Geology comments: "The San Juan Formation was deposited on an open carbonate shelf, and was bounded to the west by continental slope and oceanic basin deposits (Beresi, 1986). The diverse marine fauna and the lack of features indicative of restricted marine conditions suggest low-energy, subtidal conditions on an open platform during the entire interval of San Juan Formation deposition. The calcareous algae and cyanobacteria indicate deposition within the photic zone [...] " | |||
Taphonomy
| Modes of preservation: | cast |
| Size of fossils: | macrofossils |
Collection methods and comments
| Collection excludes: | some macrofossils,difficult macrofossils |
| Collection methods: | field collection,survey of museum collection |
| Reason for describing collection: | taxonomic analysis |
| Collectors: | M. S. Beresi |
| Collection method comments: PI-IANIGLA = Invertebrate collections of Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales, Mendoza | |
Metadata
| Also known as: | upper San Juan Fm., Talacasto Creek | ||
| Database number: | 87616 | ||
| Authorizer: | B. Kröger | Enterer: | T. Liebrecht |
| Modifier: | T. Liebrecht | Research group: | marine invertebrate |
| Created: | 2009-03-21 05:15:03 | Last modified: | 2009-03-21 15:38:29 |
| Access level: | the public | Released: | 2009-03-21 05:15:03 |
| Creative Commons license: | CC BY | ||
Reference information
Primary reference:
| 25665. | B. Kröger, M. S. Beresi, and E. Landing. 2007. Early orthoceratoid cephalopods from the Argentine Precordillera (Lower-Middle Ordovician). Journal of Paleontology 81(6):1266-1283 [P. Wagner/P. Wagner/B. Kröger] |