Los Angeles La Brea Tar Pits Home to a Century of Fossil Excavation

Los Angeles tar pits home to a century of fossil and microfossil excavation
With the Page Museum celebrating its 100th anniversary, experts believe that smaller microfossil specimens could be key to unraveling further mysteries regarding prehistoric ecosystems

Los Angeles tar pits represent a slimy wasteland, filled with the carcasses of prehistoric creatures. A diverse array of animal bones have been exhumed from the iconic La Brea Tar Pits of L.A. From saber-toothed cats to mammoths, creatures of all shapes and sizes have been discovered, interminably trapped within the dark depths of the sticky, tar-like substance.

The La Brea tar pits represent an official natural landmark, comprising of asphaltum, which continues to seep from the Earth. The tar pits that are visible today are considered the result of human excavation initiatives, involving the investigation of over 100 pits.

The chief curator of George C. Page Museum, John Harris, claims earlier excavations of the illustrious site were incomplete, missing “… a great part of the story.” According to Harris, who studied geology at the University of Leicester, Texas and Bristol, and remains head of vertebrate studies at the Natural History Museum, L.A., previous studies only

Fishbowl lab at the Page Museum
The renowned Fishbowl Lab, where paleontologists prepare fossil specimens in front of museum attendees.

acquired bones that could be seen; “hidden bones,” capable of providing crucial clues as to the environmental conditions, were neglected.

Today, the museum is celebrating a century of excavation, a period in which diggers have managed to discover around 5.5 million bones of over 600 species.

According to the Associated Press, the museum has quite a battle on its hands, sorting through the many bone samples retrieved from previous field excursions. The institution has storage rooms packed to the rafters with bones that are yet to be properly identified and catalogued; the museum estimates that there are around 100,000 specimens that require cataloguing, and over a million more to be cleaned up.

La Brea Tar Pits a Treasure Trove of Fossils

Before the Los Angeles area became the concrete jungle that it is today, hulking predators roamed the lands, including saber-toothed cats and jaguars. Ice age giants were lured to the reflective surface of the La Brea Tar Pits, where upon they started to slowly descend into the sticky tar. Over the years, waves of ancient bison, mammoths and giant sloths all fell prey to the perils of the viscous substance.

In a recent documentary for Discovery, Kristen Brown, an excavator working for the George C. Page Museum, described the unfortunate fate of these beleaguered creatures:

“The more you struggle, the more you’re stuck… it’s not a quick death, it’s a slow and painful death.”

Essentially, these prehistoric creatures would remain wedged in the pits, eventually dying of dehydration or starvation. The vulnerable corpses would serve as traps, luring a host of other creatures and opportunistic scavengers. As a consequence, rodents and swarming insects would scour the area, only to suffer the same fate.

This cyclic pattern of death has yielded one of the most prolific sites for excavation work, and remains a veritable treasure trove of Ice Age fossils.

Microfossil Analysis

At the beginning of the 20th century, researchers from the Los Angeles County Museum went to exhaustive efforts to find some of the best preserved mammalian bones. Early digs of 100 different sites were invaluable to furthering scientific understanding, but were limited in terms of scope, with many smaller specimens having been entirely ignored.

Subsequent efforts, during the late 1960s, attempted to perform more extensive excavations. Teams revisited a particular spot, called Pit 91, doubling down to find every last block of tar, bloated with precious fossil remains.

Los Angeles scientists search for microfossils after excavation
Workers from the Page Museum delicately scour collected remains, searching for tiny microfossils

After a century of digging, scientists are beginning to come to the realization that microfossils might play a critical part in reconstructing the ecological and climactic conditions at the conclusion of the Pleistocene Epoch, corresponding with the end of the last glacial period. The asphalt of the pits is capable of preserving wood and plant remnants, leaves, insects, rodent bones, mollusks and even dust and pollen.

Microfossils are delicately picked out from the matrix of asphalt and clay, removing petroleum with a solvent and using high-powered lens to separate out the most useful specimens.

Speaking to the L.A. Times, Harris talks about how his teams are now working hard to “preserve a whole prehistoric ecosystem,” whilst studying how it altered with time. Meanwhile, Luis Chiappe, vice president of research and collections at the Natural History Museum, explains that much smaller specimens, from insects to lizards and snakes, can provide information that cannot be gleaned from enormous mammoth skeletons.

One example is the skull of an unearthed saber-toothed cat, called Gimli, which was pulled from the tar pits. Alongside this skull, huge numbers of additional fragments were discovered. Shelley Cox, a laboratory supervisor at the Page Museum, found a thorax of infinitesimal size, belonging to an ant. Adding to the global picture, the teams also found ant-eating lizards next to these remains, providing obvious clues on predator-prey relationships within specific ecosystems.

This has provided an important talking point for experts in the field of paleontology, who are set to attend an event to celebrate the museums 100th anniversary on Oct. 29. In addition, the Page Museum is giving out free tickets for entrance on Monday.

The Los Angeles tar pits have been home to a century of fossil and microfossil excavation. Excitingly, it seems that the experts from the Page Museum still have much to learn about these important fossil remains.

By: James Fenner

Page Museum La Brea Tar Pits

Page Museum Staff

Natural History Museum

Los Angeles Times

ABC News

Discovery

Leave a Reply

Your email address will not be published.