La Brea Tar Pits
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Rancho_La_Brea_Tar_Pit.jpg
The La Brea Tar Pits are tar pits in the Miracle Mile district of Los Angeles, California; here buried asphalt seeps to the surface from the extensive petroleum deposits below the surface of the Los Angeles Basin. The large number of mammal fossils from the last ice age found there are the most famous, but fossilized insects and plants, even pollen grains, help fill out a picture of the cooler, moister climate of Los Angeles during the glacial age. Such microfossils are retrieved from their matrix of asphalt and sandy clay by washing with a solvent to remove the petroleum, then picking through the remains under a high-powered lens. The George C. Page Museum, part of the Natural History Museum of Los Angeles County, presents these discoveries.
La Brea is Spanish for "the tar". The 'tar' pits were used as a source of asphalt (for use as low-grade fuel or as a waterproofing or insulator) by early settlers of the Los Angeles area. The bones were taken for the remains of unlucky pronghorns or local cattle that had become mired.
Among the prehistoric species associated with the La Brea Tar Pits are mammoths, dire wolves, short-faced bears, ground sloths, and the state fossil of California, the saber-toothed cat, Smilodon californicus. Much of the early work in identifying species were performed in the early 20th century by John C. Merriam of the University of California.
Radiometric dating has given ages from preserved wood and bones of 38,000 years for the oldest known material from the La Brea seeps, and they are still ensnaring organisms today.
Rancho La Brea is the most famous, but there are two other asphalt pits with fossils in southern California: in Carpinteria, Santa Barbara County and McKittrick, in Kern County. There are other fossil-bearing asphalt deposits in Texas, Peru, Trinidad, Iran, Russia and Poland.
For other rich deposits of fossils, see Lagerstätten.
La Brea in fiction
- The tar pits, specifically the pond mammoth diorama off Wilshire Boulevard, were the place in which a volcano erupted spewing hot lava down Los Angeles streets in the 1997 movie Volcano.
- The pits were also featured in the final scene of the movie Miracle Mile, as well as several other movies representative of Los Angeles.
- In Last Action Hero, Arnold Schwarzenegger falls into the tarpits and easily wipes himself clean, prompting the kid to point out that he (Arnold) is a character in a movie and not in the 'real' world.
- The episode "That's Lobstertainment!" of Futurama depicts an animated version of the tar pits.
External references
- Page Museum website. (http://www.tarpits.org/)
- UCMP Berkeley website describes the geology and paleontology of the asphalt seeps. (http://www.ucmp.berkeley.edu/quaternary/labrea.html)
- Setting the La Brea site in context. (http://palaeo.gly.bris.ac.uk/Palaeofiles/Lagerstatten/Rancho/default.html)de:La Brea