San Francisquito Formation
The San Francisquito Formation is a geologic formation in northern Los Angeles County, California.[1][2]
| San Francisquito Formation Stratigraphic range: Maastrichtian-Danian ~70–62 Ma | |
|---|---|
| Type | Geologic formation |
| Underlies | Castaic & Punchbowl Formations |
| Overlies | San Gabriel Basement Complex |
| Thickness | 4 km (13,000 ft) |
| Lithology | |
| Primary | Sandy shale |
| Location | |
| Coordinates | 34.6°N 118.6°W |
| Approximate paleocoordinates | 39.5°N 96.5°W |
| Region | Los Angeles County, California |
| Country |  United States |
| Extent | San Gabriel Mountains & Sierra Pelona Mountains |
  San Francisquito Formation (the United States)  San Francisquito Formation (California) | |
Areas where it is exposed include: San Francisquito Canyon of the Sierra Pelona Mountains, and the northwestern side of the Devil's Punchbowl gorge in the San Gabriel Mountains.[1][2]
Geology
The San Francisquito Formation is from marine deposits of the Late Cretaceous period of the Mesozoic Era, and the Early Paleocene epoch in the Paleogene period of the Cenozoic Era.[1][2] It is overlain by the Punchbowl Formation (east) and Castaic Formation (west), both of the Miocene and Pliocene epochs.[1] It overlies the crystalline San Gabriel Basement Complex.[1]
It is found between the San Andreas Fault on its north, and the Devil's Punchbowl Fault on its south.[1][2] The Pliocene epoch Crowder Formation is to the northeast.[1]
See also
- Geology of Los Angeles County, California
- List of fossiliferous stratigraphic units in California
- Paleontology in California
- Neenach Volcano
References
- Seismo.berkeley.edu: Field Guide to the Punchbowl Fault Zone, at Devil's Punchbowl Los Angeles County Park; San Andreas Fault Resources; University of California, Berkeley; by Frederick M. Chester; January 1999.
- AAPG Datapages/Archives: "Stratigraphy and Sedimentology of the Type San Francisquito Formation, Southern California"; Department of Earth Sciences, University of California, Riverside; 1982.
- Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Archived from the original on 31 July 2014. Retrieved 8 July 2014.