Moraga Formation

The Moraga Formation, also known as the Moraga Volcanics, is geological formation that dates back to the Pliocene epoch. It is located in Berkeley Hills, East Bay Region, San Francisco Bay Area, California.[1]

Moraga Formation
(Moraga Volcanics)
Stratigraphic range: Pliocene epoch
TypeGeologic formation
UnderliesSiesta Formation
of Great Valley Group
OverliesOrinda Formation
Thickness1,200 feet (370 m)
Lithology
PrimaryBasaltic lava, with
andesite, basalt, rhyolite tuff
OtherClay, conglomerate, limestone
Location
RegionBerkeley Hills,
Alameda County and
Contra Costa County,
California
CountryUnited States
Type section
Named forMoraga Valley

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

References


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