The Repetto Formation is a
Pliocene epoch sedimentary
unit in the greater
Los Angeles Basin
The Los Angeles Basin is a sedimentary Structural basin, basin located in Southern California, in a region known as the Peninsular Ranges. The basin is also connected to an wikt:anomalous, anomalous group of east–west trending chains of mountai ...
composed primarily of
sandstone
Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
and
conglomerate.
Geology
The unit records deposition of a
submarine fan environment at lower
bathyal depths, and is recognized as a productive
petroleum reservoir
A petroleum reservoir or oil and gas reservoir is a subsurface accumulation of hydrocarbons contained in porous or fractured rock formations. Such reservoirs form when kerogen (ancient plant matter) is created in surrounding rock by the prese ...
.
[Repetto Formation, at Bureau of Economic Geology, University of Texas, Austin](_blank)
[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.]
The formation underlies the
Pico Formation, both of the
Neogene period. It overlies the
Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
-aged
Puente Formation.
Classification
The Repetto Formation is equivalent in age to the
Fernando Formation; 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 unicellular organism, single-celled organisms, members of a phylum or class (biology), class of Rhizarian protists characterized by streaming granular Ectoplasm (cell bio ...
stages.
Other researchers maintain that the Repetto and Pico Formations are distinct stratigraphic units, and that the use of the name "Fernando Formation" 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.]
See also
*
*
List of fossiliferous stratigraphic units in California
References
Pliocene California
Geology of Los Angeles County, California
Geologic formations of California
Petroleum in California
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