| Vaqueros Formation | |
|---|---|
| Stratigraphic range: Late Oligocene-Early Miocene | |
 Outcrop of the Vaqueros Formation in Gaviota State Park, California. | |
| Type | sedimentary |
| Underlies | Rincon Formation, Monterey Formation |
| Overlies | Sespe Formation, Kreyenhagen Formation |
| Thickness | 0-500+ ft[1] |
| Lithology | |
| Primary | sandstone |
| Location | |
| Region | Coastal California and the Central Valley |
| Country | United States |
| Type section | |
| Named for | Vaquero Canyon, Santa Lucia Mountains |
| Named by | Hamlin (1904)[2] |
The Vaqueros Formation is a sedimentary geologic unit primarily of Upper Oligocene and Lower Miocene age, which is widespread on the California coast and coastal ranges in approximately the southern half of the state. It is predominantly a medium-grained sandstone unit, deposited in a shallow marine environment. Because of its high porosity and nearness to petroleum source rocks, in many places it is an oil-bearing unit, wherever it has been configured into structural or stratigraphic traps by folding and faulting. Being resistant to erosion, it forms dramatic outcrops in the coastal mountains. Its color ranges from grayish-green to light gray when freshly broken, and it weathers to a light brown or buff color.[3]
- ^ Minor, S.A., Kellogg, K.S., Stanley, R.G., Gurrola, L.D., Keller, E.A., and Brandt, T.R., 2009, Geologic Map of the Santa Barbara Coastal Plain Area, Santa Barbara County, California: U.S. Geological Survey Scientific Investigations Map 3001, scale 1:25,000, 1 sheet, pamphlet, 38 p.
- ^ Dibblee, Thomas. Geology of the central Santa Ynez Mountains, Santa Barbara County, California. Bulletin 186, California Division of Mines and Geology. San Francisco, 1966.
- ^ Dibblee (1966) 40–42