Thursday, December 8, 2011

Los Angeles: California Dreamin'

What does this black, tarry goo have to do with Los Angeles. You may be surprised. Read on ...

The Page Museum at the La Brea Tar Pits

It is important to remember that Los Angeles is much more than movie stars and expensive cars. It offers a lot for a sightseer, so much so that it was difficult deciding which sites to visit. The LA Lakers play at the Staples Center and they have a huge following. But the Lakers weren’t playing so that was not an option. Since I was a young child, I have collected fossils, so it made sense for me to spend time at the Page Museum. As hard as it might be to believe, in the middle of downtown Los Angeles is something quite amazing. Bordered on both sides by heavily traveled thoroughfares sit the La Brea Tar Pits. The tar, also called asphalt by paleontologists, oozes up from the ground and bubbles. It is black and sticky and gooey. As you walk along the pathways surrounding the Page Museum, you can see and smell the asphalt. You may be wondering what is so special about black, gooey asphalt bubbling up from the ground. Buried in the tar are fossils, so many Ice Age fossils that to date more than 3.5 million have been recovered. And these aren’t just any old fossils. Many are huge like the femur (leg bone) or tusk from a woolly mammoth or exotic like the skull of a saber-toothed cat that had deadly fangs 8” long. So, how did those fossils end up in the middle of our nation’s second largest city?

Saber-toothed cat skull with 8" fangs
Long ago, before there was a city, there was land. Under the earth’s crust were cracks and petroleum-based asphalt seeped into the cracks eventually bubbling to the surface. Large pools of this tarry substance formed; some were only a few inches deep and were covered by leaves. Picture this: An unsuspecting animal such as a mammoth wanders along in search of food. He accidentally steps onto leaves covering a bubbling pool of asphalt. Quickly the animal sinks into the pool perhaps only a few inches. But he is stuck. And he cannot escape. Eventually, the poor fellow dies and his body decays leaving behind his bones, which sink into the tarry pool. Before he decays a pack of wolves or other predators may come to make a meal of the animal’s remains and they, too, become stuck. This goes on for about 28,000 years. The bones of all these animals remain buried for thousands of years perfectly preserved by the asphalt. When they are recovered all these years later, the bones are a rich brown color because of contact with the asphalt. Through carbon dating scientists have determined that the fossils range from 10,000 to 38,000 years ago. This was well after dinosaurs were gone from the earth.

Reconstructed skeletons of two short-faced bears
When you think about it, 3.5 million fossils represent a huge amount of preserved life forms. And not all of the fossils have been recovered, as excavation of the site is ongoing and has been for one hundred years. More than 650 different species of plants and animals have been recovered so far. They include at least 36 different mammals; more than 30 birds; at least 11 reptiles, amphibians, and fish; 7 arthropods; more than 11 plants.

Pit 91, which is excavated for a few weeks each summer.
If you work in Pit 91, expect to get dirty.
During a few weeks each summer, the dig site, known as Pit 91, is excavated by paleontologists who unearth about 1000 fossils each year. A lack of funds limits the amount of time the paleontologists can work. Another area called Project 23 is also underway. When the art museum next door was being constructed, a treasure trove of more fossils was discovered. They filled 23 huge crates. Each crate will be carefully unpacked and the fossils restored.  

Project 23 crates
In the middle of the Page Museum is an area called the Fish Bowl. It is a working laboratory surrounded by glass. Visitors can watch through the glass as the paleontologists and trained volunteers process fossils. Some work with large bones while others work with tiny fossils. I watched as a worker carefully sorted through what looked like extremely small pieces of gravel. She used a pointed tool to carefully sort through the pile removing any fossil material. These tiny fossils are called microfossils and they, too, tell an important part of the story of the plant and animal life that thrived here thousands of years ago.

Scientists at work in the Fish Bowl

Fossils being sorted in the Fish Bowl
Scientist sorting and identifying fossils

Sorting microfossils is a slow, meticulous process
A fossil being reconstructed in the Fish Bowl. What do you think it is? What clues help you decide?
Skull of an extinct western horse

So many dire wolves have been found that an entire wall of wolf skulls is on display.

A complete dire wolf skeleton

Look how long the tusks are on this Columbian mammoth. He stood 12' tall and weighed 1500 pounds.

This fellow is a Shasta ground sloth.

On the left is an American mastodon and on the right is an extinct camel.
This is my favorite of all the exhibits. It is a saber-toothed cat. Note: It is incorrect to call it a saber-toothed tiger.
Antique bison

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