The Pico Formation is a

Pliocene epoch The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

in the greater

Los Angeles Basin The Los Angeles Basin is a sedimentary basin located in Southern California, in a region known as the Peninsular Ranges. The basin is also connected to an anomalous group of east-west trending chains of mountains collectively known as the Tr ...

, the

Santa Monica Mountains The Santa Monica Mountains is a coastal mountain range in Southern California, next to the Pacific Ocean. It is part of the Transverse Ranges. Because of its proximity to densely populated regions, it is one of the most visited natural areas in ...

, and the

Santa Susana Mountains The Santa Susana Mountains are a transverse range of mountains in Southern California, north of the city of Los Angeles, in the United States. The range runs east-west, separating the San Fernando and Simi valleys on its south from the Santa Cla ...

, in Los Angeles County of

Southern California Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most po ...

Geology

It was formed during the

Neogene period The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. ...

of the

Cenozoic Era The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configu ...

, and overlies the

Repetto Formation The Repetto Formation is a Pliocene epoch sedimentary unit in the greater Los Angeles Basin composed primarily of sandstone and conglomerate. Geology The unit records deposition of a submarine fan environment at lower bathyal depths, and is re ...

.Blake, Gregg H. 1991. "Review of the Neogene biostratigraphy and stratigraphy of the Los Angeles Basin and implications for basin evolution," In: Biddle, Kevin T. (ed), "Active Margin Basins", AAPG Memoir 52, 319pp. Outcrops of the formation in

Santa Monica Mountains National Recreation Area The Santa Monica Mountains National Recreation Area is a United States national recreation area containing many individual parks and open space preserves, located primarily in the Santa Monica Mountains of Southern California. The SMMNRA is in t ...

have produced fossil shark teeth from the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58"Santa Monica Mountains National Recreation Area," Hunt, Santucci, and Kenworthy (2006); page 67. In addition to fossils, armored mud balls were found by Cartwright (1928) in possible fluvial or coastal deposits of the Pico Formation, though they were referred to as "pudding balls" in the article.

Classification

The underlying

is equivalent in age to the

Fernando Formation The Fernando Formation is a Plio-Pleistocene marine mudstone, siltstone and sandstone formation in the greater Los Angeles Basin, Ventura Basin, and Santa Monica Mountains, in Los Angeles County of Southern California. Geology Outcrops of the ...

, and some researchers consider it as well as the overlying Pico Formation to be a junior synonym based on benthic

foraminifera Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular Ectoplasm (cell biology), ectoplasm for catching food and ot ...

stages. Other researchers maintain that the Repetto and Pico Formations are distinct stratigraphic units, and that the use of the name "

" should be stopped due to several issues with stratigraphic correlation and access to the type section.Blake, Gregg H. 1991. "Review of the Neogene biostratigraphy and stratigraphy of the Los Angeles Basin and implications for basin evolution," In: Biddle, Kevin T. (ed), "Active Margin Basins", AAPG Memoir 52, 319pp.

References

Pliocene California Geology of Los Angeles County, California Geologic formations of California Natural history of the Santa Monica Mountains {{California-geologic-formation-stub

Geology

Classification

See also

References