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The La Brea Tar Pits are a famous cluster of
fossil sites in urban Los Angeles, around the Hancock
Park area. Brea is the Spanish word for asphalt or tar,
which has seeped up from the ground in the area for thousands
of years.
Over the centuries, animals that came to drink the water,
which collected on top, fell in, sank into the tar, and
were preserved as bones. The asphalt also preserved many
very small "microfossils" such as wood and plant
remnants, insects, dust, and even pollen grains.
Scientists have used radiometric dating of the preserved
wood and bones to estimate an age of 38,000 years for
the oldest known piece from the La Brea pits. Amazingly,
the pits still ensnare organisms today. The tar pits are
home to several excavation sites. One of them, just west
of the Page Museum is called Pit 91. Digging here began
in 1915, and it was decided it would be left as a "showpiece"
for visitors.
Unfortunately, after reaching a depth of approximately
nine feet, the excavation site suffered repeated cave-ins
and floods, and was abandoned with thousands of fossils
still awaiting excavation.
The day of June 13, 1969 became known as “Asphalt
Friday” when Pit 91 was reopened with the idea of
collecting everything that could be pulled from the earth.
That enthusiasm carried the excavation year-round until
1980 when budget constraints closed the site.
In 1984 in coordination with the Summer Olympic Games,
it was reopened and maintained until 2007, with 10 to
12 weeks of digging every summer. In all, 3,388 specimens
were recovered over 40 years, including two saber-toothed
cat skulls, six dire wolf skulls, a near-complete horse
skull, several sloth limb bones, a juvenile Shasta ground
sloth jaw, the first confirmed piece of a mammoth from
the spot.
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