USGS 13741 - Tamaulipas, Mexico (Yegua Formation): Middle Eocene, Mexico
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Gastropoda
- Ampullinidae
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| see common names | |||||||
Geography
| Country: | Mexico | State/province: | Tamaulipas |
| Coordinates: | 26.3° North, 98.8° West (view map) | ||
| Paleocoordinates: | 31.9° North, 81.7° West (Wright 2013) | ||
| Basis of coordinate: | based on nearby landmark | ||
| Geographic resolution: | outcrop |
Time
| Period: | Paleogene | Epoch: | Eocene |
| 10 m.y. bin: | Cenozoic 2-3 | ||
| Key time interval: | Middle Eocene | ||
| Age range of interval: | 48.07 - 37.71 m.y. ago |
Stratigraphy
| Geological group: | Claiborne | Formation: | Yegua | ||
| Local section: | Rio San Juan | ||||
| Regional section: | Tamaulipas | ||||
| Stratigraphic resolution: | bed | ||||
| Stratigraphy comments: The succession of Claiborne Group in northeastern Mexico is exceptionally thick and well correlated to those units of the same name in Texas on the basis of faunal similarity. The Yegua Formation is the highest formation of the Claiborne Group and has a thickness of around 1500 m. For the most part the Yegua Formation in non-marine. The lower Yegua Formation is 60 m thick and comprises about 60 ft of basal shale, clay, sand, and oyster beds and about 100 m of scarp-making sandstone, this sequence is again repeated above. | |||||
Lithology and environment
| Primary lithology: | "shale" |
| Secondary lithology: | sandstone |
| Includes fossils? | Y |
| Includes fossils? | Y |
| Lithology description: Basal shale, clay and sand. No more specific. | |
| Environment: | marine indet. |
| Geology comments: Siliciclastic, and probably very shallow water given the presence of non-marine and fluvial strata, and the occurrences of oysters. | |
Taphonomy
| Modes of preservation: | body |
| Size of fossils: | macrofossils |
Collection methods and comments
| Collection methods: | selective quarrying,field collection |
| Reason for describing collection: | taxonomic analysis |
| Museum repositories: | USNM |
| Collection method comments: Collections reposited in USGS and USNM collections. | |
| Taxonomic list comments:Exhaustive for mollusca. | |
Metadata
| Also known as: | USGS 13741 | ||
| Database number: | 43040 | ||
| Authorizer: | A. Hendy | Enterer: | A. Hendy |
| Modifier: | A. Hendy | Research group: | marine invertebrate |
| Created: | 2004-08-09 12:52:02 | Last modified: | 2025-02-22 15:12:02 |
| Access level: | the public | Released: | 2004-08-09 12:52:02 |
| Creative Commons license: | CC0 | ||
Reference information
Primary reference:
| 7474. | J. Gardner. 1945. Mollusca of the Tertiary formations of Northeastern Mexico. Geological Society of American Memoir 11 [M. Kosnik/M. Kosnik/M. Kosnik] |