Moraga Formation
| Moraga Formation (Moraga Volcanics) Stratigraphic range: Pliocene epoch | |
|---|---|
 Moraga Volcanics in Robert Sibley Volcanic Regional Preserve, Berkeley Hills | |
| Type | Geologic formation |
| Underlies | Siesta Formation of Great Valley Group |
| Overlies | Orinda Formation |
| Thickness | 1,200 feet (370 m) |
| Lithology | |
| Primary | Basaltic lava, with andesite, basalt, rhyolite tuff |
| Other | Clay, conglomerate, limestone |
| Location | |
| Region | Berkeley Hills, Alameda County and Contra Costa County, California |
| Country | United States |
| Type section | |
| Named for | Moraga Valley |
The Moraga Formation or Moraga Volcanics is a Pliocene epoch volcanic geologic formation in the Berkeley Hills of the East Bay region of the San Francisco Bay Area, California.[1]
The basaltic lava flow formation is found within Alameda County and Contra Costa County.[1][2] It can be seen in the Robert Sibley Volcanic Regional Preserve and Caldecott Tunnel area of the Berkeley Hills.[3] It is named for an exposed occurrence in the Moraga Valley.
It overlies the Orinda Formation, and underlies the Siesta Formation of Great Valley Group.[4]
- Fossils
It preserves freshwater fossils dating back to the Pliocene epoch of the Neogene period.[5]
See also[]
- Mulholland Formation — occurs to the south, in the Berkeley and San Leandro Hills.
- Pliocene California geology
- List of fossiliferous stratigraphic units in California
- Paleontology in California
References[]
- ^ a b USGS.gov: "Upper Cretaceous and Lower Tertiary Rocks Berkeley and San Leandro Hills, California", by J. E. Case, GEOLOGICAL SURVEY BULLETIN 1251-J, 1968.
- ^ Oakland Geology Blog: "Grizzly Peak and Moraga basalt"
- ^ Geology.about.com: "California Transect - Stop 30, Orinda Formation and Moraga Volcanics"
- ^ Lawrence Berkeley Lab.gov: "Berkeley Lab Geologist Studies the Ground Beneath His Feet"
- ^ Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.
{{cite web}}:|author=has generic name (help)
External links[]
- East Bay Regional Parks.org: official Robert Sibley Volcanic Regional Preserve website
- EBparks.org: Volcanism at Sibley Volcanic Preserve
 |
Wikimedia Commons has media related to Robert Sibley Volcanic Regional Preserve. |
 | This article about a specific stratigraphic formation in California is a stub. You can help Wikipedia by . |
Categories:
- Berkeley Hills
- Pliocene California
- Geologic formations of California
- Geology of Alameda County, California
- Geology of Contra Costa County, California
- Natural history of the California Coast Ranges
- Natural history of the San Francisco Bay Area
- Volcanism of California
- Pliocene Series of North America
- Pliocene volcanism
- California geologic formation stubs
- Neogene stubs