La Brea Tarpits


The La Brea Tar Pits (or Rancho La Brea Tar Pits) are a famous cluster of tar pits around which Hancock Park was formed, in the urban heart of Los Angeles. Asphalt or tar (brea in Spanish) has seeped up from the ground in this area for tens of thousands of years. The tar is often covered with water. Over many centuries, animals that came to drink the water fell in, sank in the tar, and were preserved as bones. The George C. Page Museum is dedicated to researching the tar pits and displaying specimens from the animals that died there. The La Brea Tar Pits are a now registered National Natural Landmark. Tar pits are composed of heavy oil fractions called asphalt, which seeped from the earth as oil. In Hancock Park, crude oil seeps up along the 6th Street Fault from the Salt Lake Oil Field, which underlies much of the Fairfax District north of the park. The oil reaches the surface and forms pools at several locations in the park, becoming asphalt as the lighter fractions of the petroleum biodegrade. This seepage has been happening for tens of thousands of years. From time to time, the asphalt would form a pool deep enough to trap animals, and the surface would be covered with layers of water, dust, and leaves. Animals would wander in to drink, become trapped, and eventually die. Predators would also enter to eat the trapped animals and become stuck. As the bones of the dead animals sink into the asphalt, it soaks into them, turning them a dark-brown or black color. Lighter fractions of petroleum evaporate from the asphalt, leaving a more solid substance, which holds the bones. Apart from the dramatic fossils of large mammals, the asphalt also preserves very small "microfossils": wood and plant remnants, insects, dust, and even pollen grains. Radiometric dating of preserved wood and bones has given an age of 38,000 years for the oldest known material from the La Brea seeps. They still ensnare organisms today. The Portola expedition, a group of Spanish explorers led by Gaspar de Portola made the first written record of the tar pits in 1769. Father Juan Crespi wrote, "While crossing the basin the scouts reported having seen some geysers of tar issuing from the ground like springs; it boils up molten, and the water runs to one side and the tar to the other. The scouts reported that they had come across many of these springs and had seen large swamps of them, enough, they said, to caulk many vessels. We were not so lucky ourselves as to see these tar geysers, much though we wished it; as it was some distance out of the way we were to take, the Governor [Portola] did not want us to go past them. We christened them Los Volcanes de Brea [the Tar Volcanoes]." The George C.Page Museum, part of the Natural History Museum of Los Angeles County, was built next to the tar pits in Hancock Park on Wilshire Boulevard. Construction began in 1975 and the museum opened to the public in 1977. It tells the story of the tar pits and presents specimens from them. Visitors can walk around the park and see the tar pits. On the grounds of the park are life-sized models of prehistoric animals in or near the tar pits. Of more than a hundred pits, only Pit 91 is still regularly excavated by researchers. The museum encloses the pit and tourists can watch as it is excavated for two months each summer. Paleontologists supervise and direct the work of volunteers.  In the 1920s, there were oilfields around the La Brea Tar Pits.  Gilmore Field was also located near the Tar Pits.

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DIGGERS IN La Brea TAR PIT
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LA BREA TAR PIT DIGGINGS
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La Brea Tar Pits
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La Brea Tar Pits
La Brea TarpitsDIGGERS IN La Brea TAR PIT
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La Brea TarpitsLA BREA TAR PIT DIGGINGS
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La Brea TarpitsLa Brea Tar Pits
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La Brea TarpitsLa Brea Tar Pits
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La Brea Tar Pits
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La Brea Tar Pits
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Aerial photo of La Brea Tar Pits
 
La Brea TarpitsLa Brea Tar Pits
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1920
La Brea TarpitsLa Brea Tar Pits
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La Brea TarpitsAerial photo of La Brea Tar Pits
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