Modelo Formation
| Modelo Formation | |
|---|---|
| Stratigraphic range: Late Miocene, | |
| Type | Formation |
| Underlies | Pico Formation |
| Overlies | Rincon Shale |
| Thickness | 600 metres (2,000 ft) |
| Lithology | |
| Primary | Shale |
| Location | |
| Region | Los Angeles County and Ventura County, California |
| Country | United States |
| Extent | Simi Hills, Santa Susana Mountains |
The Modelo Formation is a Miocene geologic formation in the Simi Hills and western Santa Susana Mountains of southern California, including under parts of Los Angeles.
It preserves fossils dating back to the Late Miocene of the Neogene period, among them a high number of fossil representatives of modern pelagic and deep-sea fish taxa (as well as some with benthic affinities), in addition to some seabirds and cetaceans. As suggested from this fauna, the sediments of the formation were likely deposited in a deepwater marine habitat at middle to upper bathyal depths within an abyssal fan, with geological changes along the San Andreas fault causing a rapid uplift during the latest Miocene, bringing these former deepwater sediments to the surface.[1] It is likely partially contemporaneous with the Monterey Formation in some areas, such as the Ventura Basin.[2]
Volcanic ash beds are known from the formation; these, along with fossil microorganisms, indicate that the formation was deposited between 13 to 5.5 million years ago.[3]
Paleobiota
[edit] | This section needs additional citations for verification. (September 2024) |
Based on the Paleobiology Database and Fierstine et al (2012). Much of the fauna is shared with the Monterey Formation, though some distinct taxa are also known:[4][5]
Bony fish
[edit]Many of these taxa were described by David Starr Jordan from specimens excavated during the construction of the Sepulveda Boulevard Tunnel through the Santa Monica Mountains.
| Genus | Species | Location | Member | Material | Notes | Images |
|---|---|---|---|---|---|---|
| Absalomichthys | A. velifer | Articulated skeletons | A manefish. | 
| ||
| Araeosteus | A. rothi | Articulated skeletons | A relative of the prowfish. | |||
| Argyropelecus | A. bullockii | Articulated skeletons | A marine hatchetfish. | 
| ||
| Bathylagus | B. angelensis | Articulated skeletons | A deep-sea smelt. | 
| ||
| Bolinichthys | B. sp. | Articulated skeletons | A lanternfish.[6] | 
| ||
| Chalcidichthys | C. malacopterygius | Articulated skeletons | A manefish. | 
| ||
| Chauliodus | C. eximius | Articulated skeletons | A viperfish. | 
| ||
| ?Clupea | ?C. tiejei | Articulated skeleton | A herring, classification in Clupea uncertain. | 
| ||
| Cyclothone | C. solitudinis | Lower | Articulated skeleton | A bristlemouth. | 
| |
| Decapterus | D. hopkinsi | Articulated skeleton | A mackerel scad. | 
| ||
| D. sp. | ||||||
| Diaphus | D. bolini | Articulated skeletons | A lanternfish. | 
| ||
| Eclipes | E. santamonicae | Articulated skeletons | A cod. | |||
| E. veternus | ||||||
| Etringus | E. scintillans | Articulated skeletons, isolated scales | A herring, possibly a round herring. | |||
| Ganolytes | G. aratus | Articulated skeletons, isolated scales | A herring. | |||
| G. cameo | ||||||
| Hipposyngnathus | H. imporcitor | Upper | Articulated skeletons | A pipefish. | 
| |
| Plectrites | P. classeni | Articulated skeletons | A seabream. | |||
| Quaesita | Q. quisquilia | Articulated skeletons | A deep-sea smelt. | |||
| Lampanyctus | L. petrolifer | Articulated skeletons | A lanternfish, L. petrolifer potentially in an undescribed genus. | 
| ||
| L. sp. | ||||||
| Laytonia | L. californica | Articulated skeleton | A halosaur. | 
| ||
| Lompoquia | L. culveri | Articulated skeleton | A drumfish. | 
| ||
| L. retropes | ||||||
| L. sp. | ||||||
| Molidae indet. | An ocean sunfish. | |||||
| Myctophum | M. sp. | Articulated skeletons | A lanternfish.[6] | 
| ||
| Pseudoseriola | P. gilliandi | Articulated skeletons | A relative of the bluefish. | |||
| P. sp. | ||||||
| Rhomurus | R. fulcratus | Partial skeleton | A halfbeak, either in the Hemiramphidae or the extinct Forficidae. | |||
| Sarda | S. stockii | Partial skeletons | A bonito. | 
| ||
| Scomber | S. sanctaemonicae | Partial skeleton | A true mackerel. | 
| ||
| S. cf. japonicus (=Pneumatophorus cf. grex) | Scale | |||||
| S. sp. | Mulholland Drive | Partial skeletons | ||||
| Scomberesox | S. edwardsi | Lower | Skull, partial segment with scales | A saury. | 
| |
| Scorpaena | S. ensiger | Articulated skeletons | A scorpionfish. | 
| ||
| Sebastes | S. davidi | Articulated skeletons | A rockfish. | 
| ||
| S. sp. | ||||||
| Syngnathus | S. avus | Articulated skeletons | A pipefish. | 
| ||
| Thyrsocles | T. kriegeri | Articulated skeletons | A euzaphlegid. | 
| ||
| Xyne | X. grex | Articulated skeletons, isolated scales | A herring. | |||
| Zanteclites | Z. sp. | Isolated scales | A Neotropical silverside. | |||
| Zaphlegulus | Z. venturaensis | A euzaphlegid. | 
|
Birds
[edit]| Genus | Species | Location | Member | Material | Notes | Images |
|---|---|---|---|---|---|---|
| Osteodontornis | O. orri | Sherman Oaks | A pseudotooth bird. | 
| ||
| Phalacrocorax | P. femoralis | A cormorant. | _(14).JPG)
| |||
| Puffinus | P. diatomicus | Sherman Oaks | Incomplete skeleton. | A shearwater. | 
| |
| Sula | S. willetti | Sherman Oaks | Leg bones. | A booby. | .jpg)
|
Mammals
[edit]| Genus | Species | Location | Member | Material | Notes | Images |
|---|---|---|---|---|---|---|
| Atocetus | A. nasalis | Upper | A kentriodontid toothed whale. | 
| ||
| Mixocetus | M. elysius | Lincoln Heights | Elysian Park Sandstone | Skull | A tranatocetid baleen whale, for which the formation is the type locality. | 
|
See also
[edit]
References
[edit]- ^ Rumelhart, Peter E.; Ingersoll, Raymond V. (1997). "Provenance of the upper Miocene Modelo Formation and subsidence analysis of the Los Angeles basin, southern California: Implications for paleotectonic and paleogeographic reconstructions". Geological Society of America Bulletin. 109 (7): 885–899. doi:10.1130/0016-7606(1997)109<0885:POTUMM>2.3.CO;2.
- ^ Gilbert, J. Clark; Jobe, Zane R. (2023-08-29). "Submarine-Channel Element Architecture Demonstrates Facies Heterogeneity in Both Strike and Dip Views: Miocene Modelo Formation, Lake Piru, California, USA". The Sedimentary Record. 21 (1). doi:10.2110/001c.84246.
- ^ Knott, Jeffrey R.; Sarna-Wojcicki, Andrei M.; Barron, John A.; Wan, Elmira; Heizler, Lynn; Martinez, Priscilla (2022-09-26), Aiello, Ivano W.; Barron, John A.; Ravelo, A. Christina (eds.), "Tephrochronology of the Miocene Monterey and Modelo Formations, California", Understanding the Monterey Formation and Similar Biosiliceous Units across Space and Time, Geological Society of America, pp. 187–214, doi:10.1130/2022.2556(08), ISBN 978-0-8137-2556-7, retrieved 2024-09-23
- ^ Czaplewski, John J. "PBDB Navigator". paleobiodb.org. Retrieved 2024-09-23.
- ^ California Academy of Sciences (1890). Occasional papers of the California Academy of Sciences. California Academy of Sciences. San Francisco : California Academy of Sciences.
- ^ a b Denton, John S. S. (2013). "Lanternfish (Teleostei, Myctophiformes, Myctophidae) body fossils from the Modelo Formation (upper Miocene) of Los Angeles County, California". Journal of Vertebrate Paleontology. 33 (4): 786–793. doi:10.1080/02724634.2013.751919. ISSN 0272-4634.
- Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.
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