{{Short description|Miocene geologic formation in southern California, United States}} {{Infobox rockunit | name = Modelo Formation | image = | caption = | type = Formation | age = Late Miocene, {{fossil range|13|5.5}} | period = Miocene | prilithology = Shale | otherlithology = | namedfor = | namedby = | region = Los Angeles County and Ventura County, California | country = United States | coordinates = | unitof =Los Angeles Basin | subunits = | underlies =Pico Formation | overlies =Rincon Shale | thickness ={{convert|600|m|ft}} | extent =Simi Hills, Santa Susana Mountains | area = | map = | map_caption = }}
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.<ref>{{Cite journal |last1=Rumelhart |first1=Peter E. |last2=Ingersoll |first2=Raymond V. |date=1997 |title=Provenance of the upper Miocene Modelo Formation and subsidence analysis of the Los Angeles basin, southern California: Implications for paleotectonic and paleogeographic reconstructions |url=https://pubs.geoscienceworld.org/gsabulletin/article/109/7/885-899/183276 |journal=Geological Society of America Bulletin |volume=109 |issue=7 |pages=885–899 |doi=10.1130/0016-7606(1997)109<0885:POTUMM>2.3.CO;2|bibcode=1997GSAB..109..885R |url-access=subscription }}</ref> It is likely partially contemporaneous with the Monterey Formation in some areas, such as the Ventura Basin.<ref>{{Cite journal |last1=Gilbert |first1=J. Clark |last2=Jobe |first2=Zane R. |date=2023-08-29 |title=Submarine-Channel Element Architecture Demonstrates Facies Heterogeneity in Both Strike and Dip Views: Miocene Modelo Formation, Lake Piru, California, USA |url=https://thesedimentaryrecord.scholasticahq.com/article/84246-submarine-channel-element-architecture-demonstrates-facies-heterogeneity-in-both-strike-and-dip-views-miocene-modelo-formation-lake-piru-california |journal=The Sedimentary Record |language=en |volume=21 |issue=1 |doi=10.2110/001c.84246|doi-access=free }}</ref>
Volcanic ash beds are known from the formation; these, along with fossil microorganisms, indicate that the formation was deposited between 13 and 5.5 million years ago.<ref>{{Citation |last1=Knott |first1=Jeffrey R. |title=Tephrochronology of the Miocene Monterey and Modelo Formations, California |date=2022-09-26 |work=Understanding the Monterey Formation and Similar Biosiliceous Units across Space and Time |pages=187–214 |editor-last=Aiello |editor-first=Ivano W. |url=https://pubs.geoscienceworld.org/gsa/books/edited-volume/2354/chapter/134302887/Tephrochronology-of-the-Miocene-Monterey-and |access-date=2024-09-23 |publisher=Geological Society of America |language=en |doi=10.1130/2022.2556(08) |isbn=978-0-8137-2556-7 |last2=Sarna-Wojcicki |first2=Andrei M. |last3=Barron |first3=John A. |last4=Wan |first4=Elmira |last5=Heizler |first5=Lynn |last6=Martinez |first6=Priscilla |editor2-last=Barron |editor2-first=John A. |editor3-last=Ravelo |editor3-first=A. Christina}}</ref>
== Paleobiota == 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:<ref name=":1">{{Cite web |last=Czaplewski |first=John J. |title=PBDB Navigator |url=https://paleobiodb.org/navigator/ |access-date=2024-09-23 |website=Paleobiology Database |language=en}}</ref><ref name=":2">{{Cite book |last=California Academy of Sciences |url=https://archive.org/details/occasionalpaper00calif/occasionalpaper00calif/mode/2up |title=Occasional papers of the California Academy of Sciences |date=1890 |publisher=San Francisco : California Academy of Sciences |others=California Academy of Sciences}}</ref>
=== Bony fish === Based on Fierstine ''et al'' (2012). 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.<ref name=":2" /> {| class="wikitable" width="100%" align="center" !Genus !Species !Location !Member !Material !Notes !Images |- |''Absalomichthys'' |''A. velifer'' | | |Articulated skeletons |A manefish. |frameless|195x195px |- |''Araeosteus'' |''A. rothi'' | | |Articulated skeletons |A relative of the prowfish. | |- |''Argyropelecus'' |''A. bullockii'' | | |Articulated skeletons |A marine hatchetfish. |frameless |- |''Bathylagus'' |''B. angelensis'' | | |Articulated skeletons |A deep-sea smelt. |frameless |- |''Bolinichthys'' |''B.'' sp. | | |Articulated skeletons |A lanternfish.<ref name=":0">{{Cite journal |last=Denton |first=John S. S. |date=2013 |title=Lanternfish (Teleostei, Myctophiformes, Myctophidae) body fossils from the Modelo Formation (upper Miocene) of Los Angeles County, California |url=http://www.tandfonline.com/doi/abs/10.1080/02724634.2013.751919 |journal=Journal of Vertebrate Paleontology |language=en |volume=33 |issue=4 |pages=786–793 |doi=10.1080/02724634.2013.751919 |bibcode=2013JVPal..33..786D |issn=0272-4634|url-access=subscription }}</ref> |frameless |- |''Chalcidichthys'' |''C. malacopterygius'' | | |Articulated skeletons |A manefish. |frameless|155x155px |- |''Chauliodus'' |''C. eximius'' | | |Articulated skeletons |A viperfish. |frameless |- |?''Clupea'' |?''C. tiejei'' | | |Articulated skeleton |A herring, classification in ''Clupea'' uncertain. |frameless |- |''Cyclothone'' |''C. solitudinis'' | |Lower |Articulated skeleton |A bristlemouth. |frameless |- | rowspan="2" |''Decapterus'' |''D. hopkinsi'' | | | rowspan="2" |Articulated skeleton | rowspan="2" |A mackerel scad. | rowspan="2" |frameless |- |''D.'' sp. | | |- |''Diaphus'' |''D. bolini'' | | |Articulated skeletons |A lanternfish. |frameless |- | rowspan="2" |''Eclipes'' |''E. santamonicae'' | | | rowspan="2" |Articulated skeletons | rowspan="2" |A cod. | |- |''E. veternus'' | | | |- |''Etringus'' |''E. scintillans'' | | |Articulated skeletons, isolated scales |A herring, possibly a round herring. | |- | rowspan="2" |''Ganolytes'' |''G. aratus'' | | | rowspan="2" |Articulated skeletons, isolated scales | rowspan="2" |A herring. | |- |''G. cameo'' | | | |- |''Hipposyngnathus'' |''H. imporcitor'' | |Upper |Articulated skeletons |A pipefish. |frameless |- |''Plectrites'' |''P. classeni'' | | |Articulated skeletons |A seabream. | |- |''Quaesita'' |''Q. quisquilia'' | | |Articulated skeletons |A deep-sea smelt. | |- | rowspan="2" |''Lampanyctus'' |''L. petrolifer'' | | | rowspan="2" |Articulated skeletons | rowspan="2" |A lanternfish, ''L. petrolifer'' potentially in an undescribed genus. | rowspan="2" |frameless |- |''L.'' sp. | | |- |''Laytonia'' |''L. californica'' | | |Articulated skeleton |A halosaur. |frameless|187x187px |- | rowspan="3" |''Lompoquia'' |''L. culveri'' | | | rowspan="3" |Articulated skeleton | rowspan="3" |A drumfish. | rowspan="3" |frameless |- |''L. retropes'' | | |- |''L.'' sp. | | |- |Molidae indet. | | | | |An ocean sunfish. | |- |''Myctophum'' |''M.'' sp. | | |Articulated skeletons |A lanternfish.<ref name=":0" /> |frameless |- | rowspan="2" |''Pseudoseriola'' |''P. gilliandi'' | | | rowspan="2" |Articulated skeletons | rowspan="2" |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. |frameless |- | rowspan="3" |''Scomber'' |''S. sanctaemonicae'' | | |Partial skeleton | rowspan="3" |A true mackerel. | rowspan="3" |frameless |- |''S.'' cf. ''japonicus'' (=''Pneumatophorus'' cf. ''grex'') | | |Scale |- |''S.'' sp. |Mulholland Drive | |Partial skeletons |- |''Scomberesox'' |''S. edwardsi'' | |Lower |Skull, partial segment with scales |A saury. |frameless |- |''Scorpaena'' |''S. ensiger'' | | |Articulated skeletons |A scorpionfish. |frameless |- | rowspan="2" |''Sebastes'' |''S. davidi'' | | | rowspan="2" |Articulated skeletons | rowspan="2" |A rockfish. | rowspan="2" |frameless |- |''S.'' sp. | | |- |''Syngnathus'' |''S. avus'' | | |Articulated skeletons |A pipefish. |frameless |- |''Thyrsocles'' |''T. kriegeri'' | | |Articulated skeletons |A euzaphlegid. |frameless|176x176px |- |''Xyne'' |''X. grex'' | | |Articulated skeletons, isolated scales |A herring. | |- |''Zanteclites'' |''Z.'' sp. | | |Isolated scales |A Neotropical silverside. | |- |''Zaphlegulus'' |''Z. venturaensis'' | | | |A euzaphlegid. |frameless |}
=== Birds === Based on the Paleobiology Database:<ref name=":1" /> {| class="wikitable" width="100%" align="center" !Genus !Species !Location !Member !Material !Notes !Images |- |''Osteodontornis'' |''O. orri'' |Sherman Oaks | | |A pseudotooth bird. |frameless |- |''Phalacrocorax'' |''P. femoralis'' | | | |A cormorant. |frameless |- |''Puffinus'' |''P. diatomicus'' |Sherman Oaks | |Incomplete skeleton. |A shearwater. |frameless |- |''Sula'' |''S. willetti'' |Sherman Oaks | |Leg bones. |A booby. |frameless |}
=== Mammals === Based on the Paleobiology Database:<ref name=":1" /> {| class="wikitable" width="100%" align="center" !Genus !Species !Location !Member !Material !Notes !Images |- |''Atocetus'' |''A. nasalis'' | |Upper | |A kentriodontid toothed whale. |frameless|175x175px |- |''Mixocetus'' |''M. elysius'' |Lincoln Heights |Elysian Park Sandstone |Skull |A tranatocetid baleen whale, for which the formation is the type locality. |frameless |} {{Commons category|Modelo Formation (U.S. geology)|Modelo Formation}}
==See also== {{Portal|Earth sciences|California|Paleontology}} * List of fossiliferous stratigraphic units in California * Paleontology in California
==References== {{Reflist}} * {{cite web|title= Fossilworks: Gateway to the Paleobiology Database|author= ((Various Contributors to the Paleobiology Database))|url= https://www.fossilworks.org|access-date= 17 December 2021}}
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Category:Miocene California Category:Shale formations of the United States Category:Geologic formations of California Category:Paleontology in California Category:Geology of Los Angeles County, California Category:Geology of Ventura County, California Category:Simi Hills Category:Santa Susana Mountains
{{California-geologic-formation-stub}} {{Neogene-stub}} Category:Deep marine deposits Category:Long stubs with short prose