McKittrick Tar Pits

The McKittrick Tar Pits are located in the southern part of the San Joaquin Valley about {{convert|50|km|mi|abbr=on}} west of Bakersfield and {{convert|0.8|km|mi|abbr=on}} south of the town of McKittrick.{{cite web |url=http://ohp.parks.ca.gov/default.asp?page_id=21423 |title=California State Parks-Kern County |publisher=State of California|format= |accessdate=2012-03-19}}

Most of the tar pits are located along the southwestern part of the intersection of California State Route 58 and 33 and generate from the underlying McKittrick Oil Field. The pits stretch over a distance of about {{convert|6.5|km|mi|abbr=on}}.

The asphalt lakes of the McKittrick area were probably created during the Pleistocene epoch and share the same geological principle as other asphalt lakes.

The creation of an asphalt lake is related to deep faults, often between two tectonic plates. In connection with motion along the plates or subduction, pressure is created against underlying oil source rock, in this case the Monterey Formation.{{cite web|url=http://www.gstt.org/geology/pitch%20lake.htm |title=The Pitch Lake of Trinidad |accessdate=2012-03-19 |url-status=dead |archiveurl=https://web.archive.org/web/20100131053406/http://www.gstt.org/Geology/pitch%20lake.htm |archivedate=2010-01-31 }}{{cite web|url=http://www.sjvgeology.org/geology/tarpits_geol.html|title=The McKittrick Tar Pits|last=San Joaquin Valley Geology|date=26 January 2011|accessdate=10 June 2012}}

The oil moves towards the surface and slowly transforms into bitumen and on its way picks up clay and water, and is cooled into asphalt. Lighter hydrocarbon fractions volatilize on contact with the atmosphere, leaving behind the heavier fractions, which are principally asphaltum.

Fossils that have been unearthed here include many species of American lions, short-faced bears, red deer,{{Cite journal |last1=Fox-Dobbs |first1=Kena |last2=Dundas |first2=Robert. G. |last3=Trayler |first3=Robin B. |last4=Holroyd |first4=Patricia A. |date=January 2014 |title=Paleoecological implications of new megafaunal¹⁴C ages from the McKittrick tar seeps, California |url=http://dx.doi.org/10.1080/02724634.2013.791694 |journal=Journal of Vertebrate Paleontology |volume=34 |issue=1 |pages=220–223 |doi=10.1080/02724634.2013.791694 |s2cid=128943450 |issn=0272-4634}} saber-toothed cats, ground sloths, bison, mammoths,{{Cite journal |last1=Springer |first1=Kathleen |last2=Scott |first2=Eric |last3=Sagebiel |first3=J. Christopher |last4=Murray |first4=Lyndon K. |date=April 2010 |title=Late Pleistocene large mammal faunal dynamics from inland southern California: The Diamond Valley Lake local fauna |url=http://dx.doi.org/10.1016/j.quaint.2009.10.041 |journal=Quaternary International |volume=217 |issue=1–2 |pages=256–265 |doi=10.1016/j.quaint.2009.10.041 |issn=1040-6182}} many species of birds,{{Cite journal |last=Miller |first=Loye |date=March 1935 |title=A Second Avifauna from the McKittrick Pleistocene |url=http://dx.doi.org/10.2307/1363879 |journal=The Condor |volume=37 |issue=2 |pages=72–79 |doi=10.2307/1363879 |jstor=1363879 |issn=0010-5422}} and numerous species of insects.{{Cite journal |last=Miller |first=Scott E. |date=July 1983 |title=Late Quaternary Insects of Rancho La Brea and McKittrick, California |url=http://dx.doi.org/10.1016/0033-5894(83)90067-4 |journal=Quaternary Research |volume=20 |issue=1 |pages=90–104 |doi=10.1016/0033-5894(83)90067-4 |s2cid=129331148 |issn=0033-5894}}{{Citation |doi=10.1007/978-1-4020-6359-6_3471 |chapter=Rove Beetles (Coleoptera: Staphylinidae) |title=Encyclopedia of Entomology |date=2008 |last1=Leppla |first1=Norman C. |last2=Drees |first2=Bastiaan M. |last3=Showler |first3=Allan T. |last4=Capinera |first4=John L. |last5=Peña |first5=Jorge E. |last6=Mannion |first6=Catharine M. |last7=William Howard |first7=F. |last8=Hoy |first8=Marjorie A. |last9=Al-Ajlan |first9=Abdulaziz M. |last10=Stocks |first10=Ian |last11=Raina |first11=Ashok K. |last12=Devorshak |first12=Christina |last13=Fishe |first13=Fred |last14=Garcia |first14=Lloyd |last15=Gerberg |first15=Eugene J. |last16=Gratz |first16=Norman G. |last17=Nation |first17=James L. |last18=Nation |first18=James L. |last19=Berlinger |first19=Menachem J. |last20=Verma |first20=K. K. |last21=Lecoq |first21=Michel |last22=Magalhães |first22=Bonifácio |last23=Cutkomp |first23=Lawrence K. |last24=Heppner |first24=John B. |last25=Brown |first25=Harley P. |last26=McCravy |first26=Kenneth W. |last27=Coons |first27=Lewis B. |last28=Rothschild |first28=Marjorie |last29=Lysyk |first29=Tim |last30=Lee |first30=Clarence M. |pages=3218–3224 |isbn=978-1-4020-6242-1 |display-authors=1 }}{{Cite web |title=Geology of the McKittrick Tar Pits |url=http://www.sjvgeology.org/geology/tarpits_geol.html |access-date=2023-05-14 |website=www.sjvgeology.org}}{{Cite web |title=Fossil Shells, Bones and Plants of the San Joaquin Valley |url=http://www.sjvgeology.org/geology/fossil-insects-plants.html |access-date=2023-05-14 |website=www.sjvgeology.org}}

The McKittrick Tar Pits were known by the Native American Yokuts people who mined the asphalt and used it as a sealant for waterproofing, decoration, and even for trade.

In the 1860s, San Joaquin Valley settlers mined the tar pits both from open pits and shafts and the first commercial exploitation occurred by the "Buena Vista Petroleum Company".

The tar pits have trapped and preserved hundreds of Pleistocene Age animals {{cite web |url=http://www.ucmp.berkeley.edu/about/ucmpnews/08_05/exploring08_05.php |title=Exploring California's fossil history |format= |accessdate=2012-03-19}} The first paleontological studies were conducted between 1900 and 1910, in 1928 the first major studies were conducted by a paleontological team from the University of California, the excavations were completed in 1949 by teams from the Natural History Museum of Los Angeles County and the Kern County Museum. By 1968 more than 43 different mammals and 58 different birds had been identified.{{cite web |url=http://www.geocaching.com/seek/cache_details.aspx?guid=df78d666-625d-45e9-ac24-96da38dafe11 |title=GC1EXGT McKittrick Oil Seep (Earthcache) in California, United States created by Cookie-Tree |format= |accessdate=2012-03-19}}

On June 29, 1952, the McKittrick Tar Pits were registered a California Historical Landmark.

California Historical Landmark reads:

• NO. 498 McKITTRICK BREA PIT - Located one-eighth mile west of here is an ancient asphaltum seepage in which hundreds of Pleistocene Age (15,000-50,000 years ago) birds and animals were trapped. The site was first explored in 1928 by the University of California - excavation was completed in 1949 by the Los Angeles and Kern County museums.

• California Historical Landmarks in Kern County
• California Historical Landmark

{{Reflist}}

• {{cite web |url=http://www.ucmp.berkeley.edu/images/ucmpnews/08_05/mckittrick_600.jpg |title=McKittrick Tar Pits Photo|publisher=www.ucmp.berkeley.edu |format= |accessdate=2012-03-20}}
• {{cite web|url=http://geology.about.com/od/petroleum/ig/mckittrickseep/|title=Oil Seep at McKittrick, California|accessdate=2012-03-20|archive-url=https://web.archive.org/web/20120309110149/http://geology.about.com/od/petroleum/ig/mckittrickseep/|archive-date=2012-03-09|url-status=dead}}

Category:Asphalt lakes

Category:Petroleum in California

Category:Geology of Kern County, California

Category:Lagerstätten

Category:Landforms of Kern County, California

Category:California Historical Landmarks

Category:Natural history of the Central Valley (California)

Category:Paleontology in California

Category:Pleistocene California

Category:Pleistocene paleontological sites of North America