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.
The basaltic lava flow formation is found within Alameda County and Contra Costa County. It can be seen in the Robert Sibley Volcanic Regional Preserve and Caldecott Tunnel area of the Berkeley Hills. 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.
It preserves freshwater fossils dating back to the Pliocene epoch of the Neogene period.
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