Login
Login

Capistrano Formation

{{Short description|Geologic formation in coastal southern Orange County, California}}

{{Infobox rockunit

| name = Capistrano Formation

| image =

| caption =

| type = Formation

| age = Miocene to Pliocene {{fossil range|6.6|4.9}}

| period = Miocene

| prilithology = Siltstone,

Arkose

| otherlithology = Breccia, Mudstone

| namedfor = San Juan Capistrano

| namedby = Alfred Oswald Woodford

| year_ts = 1925

| region = Orange County, California

| country = United States

| coordinates =

| unitof =

| subunits = Oso Member, unnamed siltstone member

| underlies = Niguel Formation

| overlies = Monterey Formation

| thickness = 850 m

| extent =

| area =

| map =File:Oso Member.jpg

| map_caption =Outcrops of the Oso Member, with the type locality of Titanotaria highlighted

}}

The Capistrano Formation is a geologic formation in coastal southern Orange County, California. It preserves fossils dating back to the late Miocene to early Pliocene, with the Oso Member representing a near-shore environment. Fifty-nine species and varieties of foraminifera are recognized from the Capistrano Formation alongside a diverse array of marine mammals including up to five species of walrus.

Geography

The Capistrano Formation, named for the town of San Juan Capistrano, is located in southern California, specifically the northern extent of the Peninsular Ranges, which stretch from the Los Angeles Basin to Baja California. {{Cite journal|last1=Barboza|first1=M.M.|last2=Parham|first2=J.F.|last3=Santos|first3=G.|last4=Kussman|first4=B.N.|last5=Velez-Juarbe|first5=J.|year=2017|title=The age of the Oso Member, Capistrano Formation, and a review of fossil crocodylians from California|journal=PaleoBios|volume=34|doi=10.5070/P9341033797|doi-access=free}} It crops out along the coast from Dana Point to San Clemente, and inland for seven miles.{{Cite journal|last1=White|first1=W.R.|year=1956|title=Pliocene and Miocene Foraminifera from the Capistrano Formation, Orange County, California|url=https://www.jstor.org/stable/1300262|journal=Journal of Paleontology|volume=30|issue=2|pages=237–260|jstor=1300262 }}

Geology and Stratigraphy

The Capistrano Formation is a heterogenous marine formation that can be differentiated into two distinct but adjacent units. One of these units is the Oso Member, which is composed of arkosic sandstone and preserves a nearshore environment. This unit shows outcrops across Orange County, which are recognizable as medium to coarse grained, white to tan rock. The second member primarily consists of siltstone, preserves an environment that would have been located further out at sea in deeper waters and has not yet been named. At the southwestern border of the Oso Member the two units connect.

Depending on the locality, the Oso Member of the Capistrano Formation either conformably overlies the Puente Formation (specifically Soquel Member), while in other areas it unconformably overlies the Monterey Formation and is succeeded by the Niguel Formation. The Oso Member has been dated to the early late Hemphillian (6.6 to 5.8 Ma) based on the presence of Dinohippus interpolatus and absence of older or younger taxa, but the formation as a whole extends into the Pliocene, rendering the Oso Member coeval with only the lower strata of the unnamed siltstone member. Foraminifers and microfossils have also previously been used to date the formation, which indicate an early Pliocene age (5.6 to 4.9 Ma) for its upper boundary.

Paleoenvironment

The two units of the Capistrano Formation preserve environments of difference distance from the shore. The Oso Member preserves a near-shore environment, thought to be submarine delta deposits situated in a shallow embayment of the Pacific Ocean. The presence of marlin fossils could indicate that parts of the formation deposited at bathyal depths, between 200 and 2.000 meters deep, and Fierstine argues that the preservation of the material suggests that it was not subject to extensive postmortem transportation. He also argues that the presence of this fish suggests warm water temperatures during the Miocene, with Marlins typically preferring average surface temperatures of 24 °C. Barboza and colleagues meanwhile argue that this alone is not sufficient evidence for depth, citing the preservation of marlin fossils in much shallower waters including one specimen found in deposits of the supralittoral zone. The proximity to the shore is apparent due to the presence of terrestrial fauna.

Paleofauna

=Chondrichthyes=

class="wikitable" align="center" width="75%"
Name

! Species

! Member

! Material

! Notes

! Image

Cosmopolitodus

|C. hastalis

|Oso Member

|

|also known as the broad-toothed mako

|File:Cosmopolitodus hastalis (fossil shark tooth) (Tertiary; probably from the Chesapeake Bay region, USA) 3.jpg

Myliobatis

|M. sp.

|Oso Member

|

|a species of ray

|

Otodus

|O. megalodon {{Cite journal|last1=Boessenecker|first1=R.W.|last2=Ehret|first2=D.J.|last3=Long|first3=D.J.|last4=Churchill|first4=M.| last5=Martin|first5=E.| last6=Boessenecker|first6=S.J.|year=2019|title=The Early Pliocene extinction of the mega-toothed shark Otodus megalodon: a view from the eastern North Pacific|journal=PeerJ |volume=7 |pages=e6088 |doi=10.7717/peerj.6088|pmid=30783558 |s2cid=67750037 |doi-access=free|pmc=6377595}}

|Oso Member

Siltstone Member

|teeth

|

|File:Megalodon restoration.png

=Osteichthyes=

class="wikitable" align="center" width="75%"
Name

! Species

! Member

! Material

! Notes

! Image

Acipenseridae indet.{{Cite journal|last1=Hilton|first1=E.J.|last2=Grande|first2=L.|year=2017|title=Review of the fossil record of sturgeons, family Acipenseridae (Actinopterygii: Acipenseriformes), from North America|journal=Journal of Paleontology|volume=80|issue=4|pages=672–683|doi=10.1666/0022-3360(2006)80[672:ROTFRO]2.0.CO;2|s2cid=53583501 }}

|

|Oso Member

|

|a type of sturgeon

|

Makaira

|M. nigricans {{Cite journal|last1=Fierstine|first1=H. L.|year=2008|title=A Fossil Skull of the Extant Blue Marlin (Makaira nigricans Lacepède, 1802) from the Late Miocene of Orange County, California|journal=Bulletin, Southern California Academy of Sciences|volume=107|issue=2|pages=45–56|doi=10.3160/0038-3872(2008)107[45:AFSOTE]2.0.CO;2|s2cid=26337210 |url=https://www.biodiversitylibrary.org/part/292035 }}

|Oso Member

|a nearly complete skull

|an early specimen of the extant blue marlin

|File:Blue marlin (Duane Raver).png

Oncorhynchus

|O. rastrosus{{Cite journal|last1=Sankey|first1=J.|last2=Biewer|first2=J.|last3=Basuga|first3=J.|last4=Palacios|first4=F.|last5=Wagner|first5=H.|last6= Garber|first6=D.|year=2016|title=The giant, spike-toothed salmon, Oncorhynchus rastrosus and the "Proto-Tuolumne River" (early Pliocene) of Central California| url=https://escholarship.org/content/qt84g0595b/qt84g0595b.pdf?t=pjoyct&v=lg|journal=PaleoBios|volume=33|doi=10.5070/P9331033123}}

|Oso Member

|

|the sabertoothed salmon

|File:Oncorhynchus_rastrosus_reconstruction_by_Ray_Troll.png

=Reptilia=

class="wikitable" align="center" width="75%"
Name

! Species

! Member

! Material

! Notes

! Image

Crocodilia indet.

|

|Oso Member

|A tooth and an osteoderm

|

|

Dermochelyidae indet.

|

|Oso Member

|

|

|

Testudinidae indet.

|

|Oso Member

|

|

|

=Aves=

class="wikitable" align="center" width="75%"
Name

! Species

! Member

! Material

! Notes

! Image

Mancallinae indet.{{Cite journal|last1=Morales|first1=D.|last2=Kloess|first2=P.A.|last3=Parham|first3=J.F.|year=2015|title=On the abundance of flightless auks from the middle Miocene to early Pliocene|url=https://escholarship.org/content/qt6fk763th/qt6fk763th_noSplash_5ee33e81b3b25a81963a1cd71dbadb91.pdf|journal=PaleoBios|volume=23|issue=1}}

|

|Oso Member

|

|a type of flightless auk

|

Uria

|U. sp. {{Cite journal|last1=Smith|first1= N. A.|last2=Boessenecker|first2=R.|last3=Long|first3=D.|last4=Powell|first4=C.|title=A new marine vertebrate assemblage from the Wilson Grove Formation at Bloomfield Quarry (late Miocene), Sonoma County, California|url=https://www.researchgate.net/publication/319337803|journal=Journal of Vertebrate Paleontology, Programs and Abstracts 2017, 37:195.}}

|

|

|

|

=Mammalia=

==Afrotheria==

class="wikitable" align="center" width="75%"
Name

! Species

! Member

! Material

! Notes

! Image

Desmostylus

|D. sp.

|Oso Member

|

|

|File:Desmostylus ROM.jpg

Hydrodamalis

|H. cuestae

|Oso Member

|

|a close relative of Steller's Sea Cow

|

Proboscidea indet.

|

|Oso Member

|

|

|

==Artiodactyla==

class="wikitable" align="center" width="75%"
Name

! Species

! Member

! Material

! Notes

! Image

Antilocapridae indet.

|

|Oso Member

|

|

|

cf. Balaenoptera

|cf. Balaenoptera sp.

|Oso Member

|

|

|

Camelidae indet.

|

|Oso Member

|

|

|

Delphinidae indet.

|

|Oso Member

|

|

|

Herpetocetus{{Cite journal|last1=Tanaka|first1=Y.|last2=Furusawa|first2=H.|last3=Barnes|first3=L. G.|year=2018|title=Fossil Herpetocetine Baleen Whales (Cetacea, Mysticeti, Cetotheriidae) from the Lower Pliocene Horokaoshirarika Formation at Numata, Hokkaido, Northern Japan.|journal=Paleontological Research|volume=22|issue=4|pages=295–306|doi=10.2517/2017pr025|s2cid=134686678 }}

|

|Oso Member

|

|a cetotheriid whale

|File:Herpetocetus bramblei.png

Parapontoporia

|P. pacifica {{Cite journal|last1=Boessenecker|first1=R.W.|last2=Poust|first2=A.W.|year=2015|title=Freshwater occurrence of the extinct dolphin Parapontoporia (Cetacea: Lipotidae) from the upper Pliocene nonmarine Tulare Formation of California|journal=Palaeontology|volume=58|issue=3|pages=489–496 |doi=10.1111/pala.12153|s2cid=128980362 |doi-access=free}}

|Oso Member

|a skull with associated petrotympanic

|a relative of the Chinese river dolphin

|File:Fossil whales.jpg

Physeteroidea Species A

|

|Oso Member

|

|

|

Physeteroidea Species B

|

|Oso Member

|

|

|

Tayassuidae indet.

|

|Oso Member

|

|

|

==Carnivora==

class="wikitable" align="center" width="75%"
Name

! Species

! Member

! Material

! Notes

! Image

Borophagus

|

|Oso Member

|

|a large genus of canid

|File:Osteoborus cyanoides.jpg

Mustelidae indet.

|

|Oso Member

|

|

|

Gomphotaria

|G. pugnax

|Oso Member

|

|a species of walrus

|File:Gomphotaria pugnax life restoration.jpg

Osodobenus

|O. eodon{{Cite journal|last1=Biewer|first1=Jacob N.|last2=Velez-Juarbe|first2=Jorge|last3=Parham|first3=James F.|date=2020-12-01|title=Insights on the Dental Evolution of Walruses Based on New Fossil Specimens from California|url=https://doi.org/10.1080/02724634.2020.1833896|journal=Journal of Vertebrate Paleontology|volume=40|issue=5|pages=e1833896|doi=10.1080/02724634.2020.1833896|s2cid=228814992 |issn=0272-4634|url-access=subscription}}

|Oso Member

|three skulls representing an adult male, adult female and juvenile specimen

|the first known walrus with tusks

|

Pontolis

|cf. P. magnus

P. kohnoi

|Oso Member

|

|a giant early walrus

|File:Pontolis magnus.jpg

Thalassoleon

|T. mexicanus{{Cite journal|last1=Deméré|first1=T.A.|last2=Berta|first2=A.|year=2005|title=New skeletal material of Thalassoleon (Otariidae Pinnipedia) from the late Miocene-early Pliocene (Hemphillian) of California|journal=Bulletin of the Florida Museum of Natural History |volume=45|issue=4|pages=379–411}}

|Siltstone Member

|multiple skulls and postcranial material

|a basal eared seal

|File:Thalassoleon mexicanus skull 2.jpg

Titanotaria

|T. orangensis {{Cite journal|last1=Magallanes|first1=I.|last2=Parham|first2=J.F.|last3=Santos|first3=G.|last4=Velez-Juarbe|first4=J.|year=2018|title=A new tuskless walrus from the Miocene of Orange County, California, with comments on the diversity and taxonomy of odobenids|journal=PeerJ |volume=6 |pages=e5708 |doi=10.7717/peerj.5708|pmid=30345169 |pmc=6188011 |s2cid=53020427 |doi-access=free}}

|Oso Member

|skull and postcranial material of multiple individuals

|a basal walrus

|File:Titanotaria lateral.jpg

==Lagomorpha==

class="wikitable" align="center" width="75%"
Name

! Species

! Member

! Material

! Notes

! Image

Leporidae indet.

|

|Oso Member

|

|

|

==Perissodactyla==

class="wikitable" align="center" width="75%"
Name

! Species

! Member

! Material

! Notes

! Image

Dinohippus

|D. interpolatus

|Oso Member

|isolated teeth

|

|

Rhinocerotidae indet.

|

|Oso Member

|

|

|

See also

{{Portal|Earth sciences|California|Paleontology}}

References

{{Reflist}}

  • {{cite web|title= Fossilworks: Gateway to the Paleobiology Database|url= https://www.fossilworks.org|access-date= 17 December 2021}}

{{Neogene Footer}}

Category:Neogene California

Category:Geology of Orange County, California

Category:Siltstone formations of the United States

Category:Mudstone formations of the United States