A 3579 - San Marcos Island: Early/Lower Pliocene, Mexico
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Bivalvia
- Pectinida
- Pectinidae
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Chlamys corteziana
Durham 1950
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| see common names | |||||||
Geography
| Country: | Mexico | State/province: | Baja California Sur |
| Coordinates: | 27.1° North, 112.1° West (view map) | ||
| Paleocoordinates: | 26.9° North, 110.8° West | ||
| Basis of coordinate: | based on nearby landmark | ||
| Geographic resolution: | outcrop |
Time
| Period: | Neogene | Epoch: | Pliocene |
| Stage: | Zanclean | 10 m.y. bin: | Cenozoic 6 |
| Key time interval: | Early/Lower Pliocene | ||
| Age range of interval: | 5.33300 - 3.60000 m.y. ago |
Stratigraphy
| Formation: | San Marcos | ||||
| Stratigraphic resolution: | bed | ||||
| Stratigraphy comments: The San Marcos Formation includes clastic sediments as well as gypsum, and along the southeastern shore and southern contact of volcanic rocks the base of the formation consists of 100-150 feet of volcanic sandstone and interbedded volcanic conglomerate resting on and butting into the Comondu volcanics. Marine fossils occur in sediments conformably overlying the gypsum northeast and southwest of the main gypsum area. The lower part of the section is volcanic sandstone, while the upper part is calcareous conglomerate and pebbly limestones, locally quite fossiliferous. Collection from boulder from fossiliferous beds above gypsum on southern end of island. | |||||
Lithology and environment
| Primary lithology: | volcaniclastic poorly lithified sandstone |
| Secondary lithology: | shelly/skeletal calcareous conglomerate |
| Includes fossils? | Y |
| Includes fossils? | Y |
| Lithology description: Volcanic sandstone, calcareous conglomerate and pebbly limestones, locally quite fossiliferous. | |
| Environment: | marine indet. |
| Geology comments: Generalized environmental limits of 0-185 m | |
Taphonomy
| Modes of preservation: | body |
| Size of fossils: | macrofossils |
Collection methods and comments
| Collection methods: | field collection |
| Reason for describing collection: | biostratigraphic analysis |
| Museum repositories: | UCMP |
| Collection method comments: Material reposited in the UCMP collections. | |
| Taxonomic list comments:Exhaustive. Identified by J.W. Durham. | |
Metadata
| Also known as: | A 3579 | ||
| Database number: | 44031 | ||
| Authorizer: | A. Hendy | Enterer: | A. Hendy |
| Modifier: | A. Hendy | Research group: | marine invertebrate |
| Created: | 2004-08-31 08:20:44 | Last modified: | 2013-11-25 13:37:23 |
| Access level: | group members | Released: | 2005-08-31 08:20:44 |
| Creative Commons license: | CC BY | ||
Reference information
Primary reference:
| 11549. | J. W. Durham. 1950. 1940 E.W. Scripps cruise to the Gulf of California. Part II - Megascopic paleontology and marine stratigraphy. Geological Society of America Memoir 43(2) [A. Miller/A. Hendy/A. Hendy] |