Moraga Formation (Moraga Volcanics) | |
---|---|
Stratigraphic range: Pliocene epoch | |
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, also known as the Moraga Volcanics, is a geological formation that dates back to the Pliocene epoch. It is located in Berkeley Hills, East Bay Region, 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]
It preserves freshwater fossils dating back to the Pliocene epoch of the Neogene period.[5]